This page collects work comparing various knives to summarize the information gathered on blade materials and as well provide additional reference links on material properties.
Composition tables/information :
Tool steel name cross reference information :
Heat treating :
Maker commentary :
Materials information :
Steels discussed :
The specifications for 52100-B is the composition of an individual blade.
1095 is a high carbon steel steel, usually water quenched. It can reach 66 HRC and has moderate wear resistance and good to high impact toughness. It is very shallow hardening though not a concern for cutlery as knives as made from thin stock. The fracture grain size is 9. Some specification and performance data sheets on 1095 from various manufacturers :
Other materials data :
Note the embrittlement zone at 500 F which gives a rockwell hardness of 60 HRC. This is a common problem with carbon and low alloy steels. This region should generally be avoided and if the performance at the lower temperature is not satifactory then instead of using a high draw which will readily sacrifice strength (see the stress/strain graph) switch to a lower carbon steel which has a higher toughness at the lower temper and/or examine bainite hardening.
Other reference information :
Knives personally used in 1095 :
The Ontario machetes had better edge retention than the Tramontina on light brush and wood work however the suffered gross damage losing large pieces out of the edge on hard woods. The Ontario Spec Plus knives, also had problems; one blade was too brittle, another had an unhardened tang, and one was even ground the wrong way, the edge was thicker than the spine. The Ontario RTAK also took severe damage damage readily cutting thick woods due to problems with the grind which induced more severe problems when the blade was used clipping off branch stubs it rippled along the entire edge. Similar problems have been reported on the internet with other RTAK's including gross damage chopping light wood.
The Livesay RCM also deformed during limbing though not as severe as the Ontario's. The custom RTAK from Livesay did not have such a problem and the performance was solid for a wood cutting tool.
The TOPS Steel Eagle also had several problem in regards to brittle fracture. The teeth cracked when used as wire breakers) and the tip and edge cracked when digging an arrow head out of a piece of wood ref. It also had poor edge holding compared to a Battle Mistress in INFI on both on carpet and wood.
The narrow Mora had problems with brittle tip fracture on light work and in general the edge retention was low on hemp and carpet.
The custom paring knife was heat treated to maximize torsional toughness and give a very high torsional strength and ductility and compressional strength at a hardness of 66 HRC. The edge had a very thin profile and a very acute grind yet was still able to cut woods, bone and even sod with no significant damage . The edge holding in general was also very strong easily outlasting a small Sebenza in S30V cardboard with both blades sharpened to fine angles) as did very well on used carpet.
Summary : While the performance of 1095 in the above blades was problematic at times this isn't due to the inherent performance limitations of 1095 but quality control issues and choices of heat treatment. Note the hardness values listed can either fall either in the embrittlement region or one of very low strength see the impact touhness and stress/strain graphs. The custom RTAK from Livesay and paring knife Johnson showed the abilities of 1095 in a large and small blade respectively.
52100 is a high carbon steel with a small amount of manganese and chromium to deepen hardening and slow down the isothermal transformations (pearlite/bainite) which allow oil vs water quenching, as quenched hardness is up to 65/66 HRC with cold treatments. At an austenizing temperatures of 1550 F there is 0.55 to 0.6% of carbon dissolved and thus lathe martenize rather than the more brittle plate martensite will form. The dissolved chromium will also give superior corrosion resistance to O1 but lower than 52100 has a grain fracture size of 9. Some specification and performance data sheets from various manufacturers :
Maker comments :
Knives personally used in 52100 :
The Blackjack small was used for a lot of work, in regards to edge retention it was well behind several high alloy steels on slicing cardboard with various edge finishes : ref.
Ray Kirk's test blades were made from 1084, L6, 52100 and D2 at various hardness levels, which were used unmarked so the steel types were unknown until after the work was completed to examine sharpness and edge retention on used mats, as well as ease of sharpening and durability by cutting bone and concrete. At high sharpening angles (20 degrees) there was no difference in initial sharpness. In edge retention on the used mats the D2 blade consistently outlasted the 52100 knife on the mat cutting which out cut the other two steels : ref. On the bone cutting the L6 blade fared the worst due to the low hardness : ref. On the concrete cutting the 52100 blade had the best balance of strength and durability to minimize damage : ref. While there was a large difference in machinability, the blades which sharpened the fastest tended to be just the ones which suffered the least damage or wear in use, so either D2 or 52100 depending on what was cut.
Ray's ABS bowie was used for a lot of wood work and rope cutting and found to have lower edge retention than a straight handled Battle Mistress (INFI) on cutting used poly, however the edge angles was lower on Ray's knife and it still cut significantly better even when the edge was degraded : ref. The bowie was also subjected to both light and hard impacts off of a concrete block and it did well taking only minimal edge damage inspite of its very acute edge profile, and was much more durable than a tactical knife from Strider in a much thicker edge profile : ref.
The MEUK in 52100 was several blades on used carpet and it had significantl better edge retention than a Swiss Army knife, a custom in LM1 and another 52100 blade by Ed Fowler though was behind another custom in CPM-10V : ref. The MEUK was also well behind several high alloy steels slicing carpet : ref. One of the main drawbacks to 52100 is the low corrosion resistance, and this was evident with the MEUK which would developed a patina quickly in the kitchen on acid foods.
Ed Fowler's Pronghorn was used for a lot of work include cutting hemp where at best it matched the performance of an Opinel : ref. On used carpet it did poorly, being outperformed by a Swiss Army knife : ref. On lateral loads it did very poorly showing little flexibility and taking a set immediately and being very easy to bend, acting essentially like unhardned steel : ref.
Summary : 52100 is advocated by some as an ideal blade steel, very fine grained with a solid combination of edge retention over a wide range of materials due to its combination of hardness, wear resistance and toughness. Ray Kirk's and Ed Caffrey blades certainly showed these abilities.
This is one of the more common carbon steels in the cutlery industry, however it is rarely called by that name. Cold Steel calls it Carbon V, Camillus calls it 0170-6C, and Case calls it "chrome vanadium", W7 is tool steel with a similar composition.
Knives personally used in 0170-6C / Carbon V :
The Twistmaster was used for a lot of hemp rope cutting and with a fine ceramic finish at 22 degrees per side it had only a fraction of the edge retention of a D2 custom from Mel Sorg at 62 HRC. With the edge sharpened to a fine diamond finish at the same angle, it was identical to the Becker CU/7 once the edge had been reprofiled to a similar level of cutting ability by adjusting the angle which makes sense as they are the same steel at the same hardness. It was however significantly behind higher and harder alloy steels such as VG-10 and D2.
The Machax was used for a lot of wood work compared to multiple large blades, the edge retention was much lower than the Busse Battle Mistress. The Machax took edge damage in the form of chips and dents cutting hard woods with the stock profile. With the edge angle reduced the damage was much reduced but the edge retention was much lower than on the Battle Mistress as the edge would lose slicing aggression much faster. The Machax was also given a soak in salt water and as expected the blade formed surface rust readily but didn't tend to pit.
The Patrol Machete was used on a variety of light vegetation where it did well, however it took gross damage on light limbing. A replacement suffered extensive edge damage on the same work and then cracked easily with a few light slap on a log. While the edge was too thin which can be used to argue for the rippling, there was gross fracture under far too low a level of stress.
The Becker CU/7, similar to the Twistmaster, also had a large disadvantage compared to the Sorg Custom, this time the comparisons was at a very rough finish, left by a 100 grit aluminum oxide belt. The Becker was not even in the same class. With a much reduced edge profile the CU/7 was subjected to very hard impacts, the edge fractured readily, but there was no gross damage up into the primary grind as seen for example with the WB from Strider.
The Combat Bowie was used for some bone chopping compared to the Camp Tramp in SR101 and had a slight advantage after a short round of bone cutting with both blades at similar angles and finishes. However the much higher chopping ability of the Becker would give it an advantage and in general this type of work needs to be repeated to insure that it isn't just bone variance or a bad swing. However it would be reasonable to conclude the edge durability is at least similar in class.
Overview : This steel is one of the most common production grade cutlery steels, called different names by different manufacturers. It is basically a low alloy enhancement of 1095 designed to give deeper hardening, refine the grain and as well provide slight increases to wear resistance and corrosion resistance. The performance seen in production knives was significantly varied which is common with the more inexpensive blades.
Steels discussed :
L6 is a lightly alloyed medium carbon steel which allows oil hardening and has a slight improvement in wear resistance over the plain carbon steels and gives deeper hardening. It has very low corrosion resistance. It can readily reach full martensite hardness of 65/66 HRC. The grain fracture size is 8.
Maker comments :
Knives personally used in L6 :
Ray Kirk's test blades were made from 1084, L6, 52100 and D2 at various hardness levels, which were used unmarked so the steel types were unknown until after the work was completed to examine sharpness and edge retention on used mats, as well as ease of sharpening and durability by cutting bone and concrete. At high sharpening angles (20 degrees) there was no difference in initial sharpness. In edge retention on the used mats the D2 blade consistently outlasted the 52100 knife on the mat cutting which out cut the 1084 blade which outclassed the much softer L6 blade showing the heavy influence of hardness : ref. On the bone cutting the L6 blade fared the worst again due to the low hardness : ref. On the concrete cutting the 52100 blade had the best balance of strength and durability to minimize damage, the L6 blade again suffered due to lack of compression resistance : ref. While there was a large difference in machinability, the blades which sharpened the fastest tended to be just the ones which suffered the least damage or wear in use, so either D2 or 52100 depending on what was cut.
The Running Dog Traditional Tanto is made from 15n20, a swedish bandsaw steel very similar to L6. It was compared to a D2 custom from Mel Sorg (62 HRC, full cryo) which showed superior edge retention on hard woods : ref. The corrosion resistance was quite low, it would rust in minutes when exposed to food acids : ref.The Tanto was also compared to a Sub Sniper cutting wood and had significantly lower edge retention, but the much greater machinability allowed similar sharpening times : ref.
Summary : The material properties of L6 are very well suited to large blades as it a very tough steel, and can also be readily heat treated to form bainite which is much tougher than martensite at similar hardness. The above blades could not readily examine these attributes as the L6 test blade by Kirk was severely hampered by lack of hardness and the Running Dog Tanto was not examined in regards to durability as it was just on loan.
The following specifications cover O1 Tool Steels :
Nominal composition of O1 :
As a bit of detail on the composition, as noted in the image on the right, it only requires a maximum of 0.6% carbon to produce maximum hardness, above that there is very little increase and there are issues with retained austenite and formation of plate (vs lathe) martensite. Why then does O1 have such a high level of carbon?
The extra carbon will form carbides which are much harder than the steel (martensite) such as cementite, and more importantly since O1 has a small but significant amount of alloy carbide formers in Tungsten, Vanadium and Chromium, all of which will tie up carbon in the formation of carbides. The carbon needs to be increased above 0.6% to ensure that a free amount of carbon is left to go in solution in the martensite to enhance the hardness.
In regards to the carbide formers, the tungsten and vanadium are mainly there as they will not dissolve in the austenite and thus they pin the austenite grains as they form and thus keep the grain very small which increases the strength and toughness of the steel. These very small and very hard carbides are much harder than the martensite and the cementite 1 and thus will contribute to the low stress abrasive wear resistance over a pure carbon steel such as 1095. However to really make this significant then a lot more Tungsten is needed, several percent such as steel in the cold work grades such as F2. 2
The other significant alloy influence in O1 is the manganese which is very beneficial to steels in many respects (it is a deoxidizer) and chromium, and to a lesser extent the silicon. These elements all increase the hardenability, or ease of forming martensite. This is why O1 can oil harden but 1095 for example needs a much faster quench and is usually water hardened. For the knife user, this makes little effect, but for the knife maker, not having to deal with the extreme quench of water and the risk of cracking can be of benefit.
The chromium in the steel increases the hardenability by reducing the high temperature diffusion reactions. This means as the blade cools, the chromium stops pearlite from forming The manganese addition has a similar effect, it also reduces the formation of pearlite, but it does so in another way. manganese expanding the austenite phase to being stable (existing) lower temperatures. This ideally prevents the ferrite from forming until ideally the temperature has been reduced by the quench to the point martensite starts to form. These alloy additions to O1 over the plain carbon steels and the effect they have on the reduction of the pearlite and thus the increase in the hardenability can be readily seen in the TTT curves to the right.
O1, like most of the high carbon or high alloy steels can benefit from an extended quench where the steel is taken to below room temperature. The main reasons for this are the :
The combination of these two effects can produce an increased hardness of 2-3 HRC points and an increase in low stress wear resistance by a factor of 2. 2a .
What does all of this mean as to how the steel performs? As always, it is of benefit to look at some comments/feedback on steels from the woodworking industry as it is a very common chisel and plane steel. In general O1 is considered an entry level steel for such materials when compared to White, Blue and HSS chisels using M2 or similar steels. All of these materials will have a significantly higher carbide content, but still retain a very fine, well distributed carbide network as noted in the image on the right. 3 The apex stability in M2 and similar steels is therefore still high enough they tend to blunt by slow wear and can maintain a high sharpness.
The PM-V11 and the White Steel really do deliver. The gap between them and the A2 and O1/HCS is very large.
Now a frequent point of contention in such materials is O1 vs A2 and in general the argument is A2 will make a stronger and more wear resistant edge but it is harder to grind :
A2 is a great steel that offers a real improvement in edge retention. O1, on the other hand, is still preferred by many for its relative ease of sharpening and its ability to get sharper.
However the difference in these materials in terms of abrasive wear resistance is actually quite small and they both have the same working hardness ranges and maximum obtainable hardness. In practice then what is often seen in terms of one out performing the other is dependent more on which manufacture made which chisel in a particular steel and the random stresses on it in a particular use. Brent Beach for example compared a large range of planes in various steels and while the HSS blades in M2 did consistently offer superior performance the performance of A1 vs O2 was just a random spread around each other :
Lee Valley A2 , 6 Lie Nielsen A2 , 6 Lee Valley block plane A2 , 12 Lie Nielsen #62 O1 , 18 Hock O1 , 9 Knight O1 , 6
While the data show a weak increase in performance of A2 over O1, the numbers listed (which are the wear bevel sizes) differ in the random spread much larger than the difference between them so there is no statistical significance. Beach was also doing a very controlled comparison, in normal work it is even more unlikely a consistent performance increase would be seen unless careful observations were made over a very long time period.
Knives personally used in O1 :
In regards to the Uddo in O1, it was used for extended slicing comparisons on 1/2" hemp and cardboard and performed well, similar to other steels in its class in regards to generally blunting by slow wear and resisting chipping and significant deformation. In order to have the performance significantly exceeded in regards to edge retention it was necessary to step up to steels such as Elmax and M4, or use a steel similar to this one, but hardened differently such as customs in 1095 which are at maximum hardness, 66/67 HRC. Of course while the edge retention slicing abrasive materials is higher in those examples, they trade off grindability and toughness to obtain the higher strength and wear resistance.
On harder work, cutting carpet. an example of the kind of tradeoff in terms of toughness and how it influences performance can be seen. used carpet. The O1 blade from Uddo shows its versatility here compared to various steels as it could easily do extended slicing without any significant damage and just blunted by slow wear. The fact that it takes no visible damage in such work has a significant effect on the ease, or speed of resharpening. The top performance in edge retention in that comparison was seen in S30V. However the O1 blade was significantly easier to grind and when the two are combined to represent a kind of edge retention - efficiency measurement then the O1 is ahead of the S30V. Now of course if the knife is power sharpened or very coarse / high end stones are used to grind it, then this kind of measurement is moot as grinding speed can be rapidly reduced in such methods.
The same kind of benefit was seen to an even greater extent when the knife was used to cut up some sods alongside a few other folders. It was among the fastest to sharpen as it again took very little damage and the steel has a high grindability.
In regards to sharpening, O1 in general gets high praise for ease of sharpening, not only as noted by the woodworkers as noted previously but by knife users as well. It is one of the easier to sharpen steels possible as it has :
As this blade is hardened for high durability, then it compromises a little on the edge retention in light use for performance in light use as noted in the above. However This means that in general the chip resistance is fairly high (compared to steels such as D2, TS-34, 10V) and in heavier use it can excel where such steels would chip. In general due to the combination of toughness and strength the edge tends to blunt by slow wear as noted in the image on the right which also increased the ease of sharpening by reducing the necessary grinding as seen in the carpet cutting previously.
The TUSK from McClung, handled low stress cutting well and the hard edge stayed crisp a long time cutting wood, ropes and other soft media. However it chipped badly cutting light sheet metal and suffered gross damage readily on edge torques, a replacement fractured in the same manner, the maker claimed abuse. The behavior may be explained by the above torsional graph which shows strong embrittlement regions for O1 in both torsional impact and strength with a low ductility.
A pATAK in O1 from McClung also suffered gross damage during a review. A Howling Rat was personally used to do the same work with no damage. Mike Turber also compared a ATAK in O1 from McClung to several other knives and it also suffered edge chipping cutting woods. This, as is common with critisms of McClung's knives caused significant controversy as McClung claimed the knife was a fake inspite of the knife being bought from an offical dealer of McClung's knives and other customers reporting the same behavior on multiple knives from McClung. Will Kwan also noticed problems with prying in woods as well as light chopping into metals scan down through this cashed link of a deleted thread to see Kwan's commentary.
The Randall #1 in O1 didn't have problems with chipping however due to the low hardness (55/56 HRC) the edge retention was in general lower than slightly harder Randall #5 in 440B stainless. The 440B Randall also has of course a much greater corrosion resistance, the O1 blade will patina visibly while cutting acidic foods. When compared to harder and more wear resistant alloys such as S30V, a production folder out cut the O1 Randall by about 3:1 on cardboard. The O1 Randall machined very easily as it was soft enough to file, the low hardness does mean it could be problematic to get a crisp edge on v-rod rigs.
As with all steels, heat treating is critical. The custom O1 blade at 63.5 HRC was compared to a Sebenza in S30V on cardboard with both sharpened to very low edge profiles, the performance was reversed from seen on the Randall and the O1 blade had much better edge retention. It also did very well slicing used carpet. It formed a patina very fast when exposed to food acids.
Summary : O1 is a general purpose tool steel known for moderate wear resistance and toughness and low corrosion resistance. It makes a very nice light utility knife. Its performance in larger knives was not as impressive but may be due more to choices in heat treating rather than intrinsic properties of the steel.
A2 is an air hardening cold work die steel. The significant amounts of chromium and molybdenum makes it more dimensionally stable than O1. They also require much higher austenization temperatures to dissolve than the water/oil hardening steels and thus A2 is typically austenized at 1750/1800 F. The heating is usually done in stages to minimize thermal gradients in the steel and reduce the hold time at the austenization temperature to prevent grain growth.
The dissolved alloy elements and high carbon content will cause significant percentage of retained austensite if the quench is halted at room temperature and result in a loss of 2.5-3 HRC points. With oil + cold A2 can can harden up to 64/65 HRC and will resist significant softening up to 1000 F (57/59 HRC). A2 has moderate wear resistance (A2 is 6, O1 is a 4 and D2 is an 8 : ref) and good impact toughness. The grain fracture size with standard industy heat treatment is 8.5. Some specification and performance data sheets on A2 from various manufacturers :
Materials data :
Maker commentary :
Knives personally used in A2 :
The Mission MPK took edge damage chopping while the Recon Scout from Cold Steel in Carbon V did not, which may simply be an issue of hardness. The MPK also had much lower edge retention on hemp with a DMT 600 finish compared to a Becker CU/7 which is also made from the same steel as the Recon Scout. The Mission was problematic in regards to durability and cracked in half under a light impact from a framing hammer in an attempt to cut a piece of tension bar (mild steel), no progress was made on the bar cut. Much higher durability has been seen with other blades such as the TAC-11 and Howling Rat).
The Project I, similar to the MPK also showed damage readily just on wood chopping.
Summary : A2 is an air hardening tool steel known for a solid combination of wear resistance and toughness. The personally used knives were not impressive in regard to durability or edge retention however this is more likely an issue with choice of heat treatment. One of the reasons could be large amounts of retained austenite which will transform to untempered martensite over time, expecially with heavy work which leaves the steel very brittle.
D2 is a cold work die steel with a much higher alloy content than A2, specifically the chromium and carbon percentages are both increased to generate a large volume of chromium carbide. D2 is typically austenized at just slightly higher temperatures, 1850 F, which like A2 is usually done in stages. It has very high wear resistance due to the carbide content which also lowers machinablity and grindability. The corrosion resistance is high for a tool steel, significantly more than A2 and it resists forming a patina strongly. D2 however doesn't have the corrosion resistance of martensitic stainless steels as most of the chromium in D2 is in the form of primary carbides due to the high carbon content and low austenizing temperatures.
D2 has a coarse carbide structures, the primary chromium carbides which can be up to 50 microns in length, the fracture grain size is 7.5. It is commonly used in industry for punches, dies and various types of knives. It has significant retained austenite retained after quenching to room temperature which can be reduced by cold treatments. It has a very wide temper range from 300F for maximum hardness (64 HRC) and wear resistance, up to 950F (58/60 HRC) for toughness. The high temperature tempers will transform retained austenite to martensite in the cooling to room temperature after the tempering, as the ausentite is conditioned by carbide precipitation during the temper which raised the Ms point. Generally multiple tempers should be used to temper the freshly transformed martensite.
D2 can also be soaked much hotter, up to 2050 F, which forces much more of the alloy content into the austenite which lowers the Ms point and produces a lower as quenched hardness. However there is now a much greater secondary hardening responce which can increase the hardness well above the as quenched hardness due to secondary carbide precipitation and the transformation of the retained austenite to martensite. Some specification and performance data sheets on D2 from various manufacturers :
Other reference information :
Knives personally used in D2 :
The Deerhunter in D2 was compared to identical blades in AUS-8 and VG-10 stainless steel. In edge retention on hemp rope the D2 blade could cut double the amount of the VG-10 blade before achieving a similar state of significant blunting, and the VG-10 knife 50% more than the AUS-8A. However when the influence of corrosion was added by soaking the blades in lemon juice, the D2 blade was far behind the two stainless steels which were similar in edge retention on the hemp. The blade were also used for hard work, batoning, cutting bone and metal and impacted into concrete. The VG-10 blade consistently showed the lowest durability and the D2 the highest.
Ray Kirk's test blades were made from 1084, L6, 52100 and D2 at various hardness levels, which were used unmarked so the steel types were unknown until after the work was completed, to examine sharpness, edge retention on used mats, ease of sharpening and durability by cutting concrete. At high sharpening angles (20 degrees) there was no difference in initial sharpness. In edge retention the D2 blade consistently outlasted the 52100 knife on the mat cutting which out cut the other two steels. On the concrete cutting the 52100 blade had the best balance of strength and durability to minimize damage.
The Dozier Agent was compared to the Safari Skinner on cardboard to check it compared to another D2 blade and no significant difference was observed in edge retention in both push/pull sharpness : ref. The K2 from Dozier was compared to a small Sebenza in S30V from Chris Reeve knives on slicing cardboard and there was no significant difference in slicing edge retention between the two : ref. The K2 was also used to slice used carpet and compared to numerous other knives where it did well in general, though was outperformed by several very hard tool steels : ref. The Agent was also compared to a S30V Paramiltary from Spyderco cutting used carpet, and the edge retention was similar when the material was dry, however with cutting performed in the rain the D2 blade fell behind showing the influence of the lower corrosion resistance of D2 vs S30V : ref 1, 2. In regards to heavy impact, the Dozier Agent was subject to a variety of impacts off of hard objects and was readily outperformed by tougher steels like SR101 : ref.
Two Spyderco Folders in S30V were compared to the Heafner bowie in D2 for edge retention on used carpet and the same behavior was noted in regards to rusting effecting edge retention : ref. In that case the D2 blade was further behind as the rain was heavier. The Heafner bowie also showed one of the drawbacks for D2 in large blades as when it accidently hit a rock when clearing some grasses the edge chipped readily : ref. However Swamp Rat knives have demonstrated highly levels of impact toughness with their D2 : ref.
The custom from Mel Sog was used to cut a lot of hemp with various edge finishes and profiles showing the influence of both and how D2 makes an excellent rope slices with a thin edge and x-coarse finish : ref.
The Uluchet was used for a lot of wood cutting and in general performed well, it has a fairly robust edge profile which allows it to resist damage from woods and even bone. It was also able to be used as a baton impact tool with no problems.
There was little done with the Cuda MAXX as it was bought mainly to check the ability of the knife to take "flicking", intertial wrist openings.
Summary : D2 is a tool steel known for high wear resistance through its very heavy chromium carbide content and high obtainable hardness. In general it makes a nice steel for fine cutting blades, at moderate sharpening angles, and especially for coarse finishes. The corrosion resistance is high for a tool steel, though it tends to pit readily in salt water soaks, and the resistance to impact is also low. There is quite a bit of variation in regards to durability, Swamp Rat D2 and Dozier's D2 were seen to be extremely different.
INFI is a propriety steel used by Busse Combat through hardened to 58/60 HRC.
The performance of INFI in the blades of Busse Combat has been demonstrated live by jerry Busse at live and public demonstrations at knife shows, as well as in videos and pictures, these include thousands of push cuts on full once inch hemp rope without sharpening, cuts though a hanging bundle of 10 strands of inch hemp, multiple 2x4's chopped with the knife still shaving, and very heavy prying loads and bends to a very high degrees without breaking on a fully hardened blade.
Knives personally used in INFI :
The straight handled Battle Mistress easily outlasting a TOPS knife in edge retention on both carpet and wood.
The battle Mistress E was used for very heavy work to check durability and the performance was very high, resisting hammer impacts, cuts into nails, concrete and even rock with minimal damage.
The badger Attack 3 was used mainly as a heavy utility knife and with a custom modified edge profile worked extremely well as a heavy wood craft blade.
Summary : INFI is a tool steel known for overall solid performance with a excellent balance of corrosion resistance, toughness and edge retention. It makes a superb large blade as well as smaller blades which need to handle tougher work.
M2 is a high speed steel (HSS) which means it retains its hardness at the high temperatures induced from cutting at high speeds. High speed steels achieve this "hot hardness" through the use of alloy elements such as W, Mo and V to form secondary carbides during tempering. They require very high austeniting temperatures (2250F-2350F) to dissolve the alloy carbides. M2 is air hardening up to 66/67 HRC with oil quench and cold treatements and has very high wear resistance and low impact toughness, this is the hardness in hacksaw blades. The fracture grain size for HSS is 9 to 9.5. Some specification and performance data sheets on M2 from various manufacturers :
other materials data :
Maker perspective :
Knives personally used in M2 :
The mini-AFCK was compared mainly to a AUS-8A stainless steel blade from spyderco and found to have better edge retention in cutting cardboard, plastics, and insulation. It also sharpened easily to a very fine edge.
Summary : M2 is a HSS tool steel which high obtainable hardness and wear resistance with low impact toughness. It has a very fine grain structure and makes an excellent low impact cutting knife. The corrosion resistance is lower than stainless cutlery steels but high in general for a tool steel.
M4 is a well known steel which gained significant popularity in the knife industry being strongly promoted by Crucible marketing it as CPM M4 : data sheet and in particular as having a high toughness. Note that data sheet was made before the steel was promoted for knives hence the toughness shown is fairly low as it is being hardened as a HSS would in the tool industry. However even when tempered to lower hardness the impact toughness is still lower for example than A2 as commonly used in knives ref and is in the same range as the high carbide stainless steels ref. EraSteel also has a more comprehensive data sheet on PM M4 as well.
Now while it has been promoted as being tough because of use as in the BladeSports competition blades it has to be realized that :
There was a fairly well kept secret for a number of years that the M4 blades when first used would actually suffer extreme brittle failure. To prevent this the blades were severely under hardened by lowering the soak temperature. However even with such underhardening the blades still have a very short lifetime which has been confirmed by multiple makersEd Schempp .
Aside from the promoted toughness, the main selling point of CPM M4 is the edge retention which is expected as it is one of the harder and more wear resistant of the HSS. However general knife heat treatment is very different than how it is hardened in industrial cutting tools (due to durability concerns) so care has to be taken when looking at materials data sheets. However in general it will tend to do well in cutting cardboard and various ropes hence why it usually gets very positive comments from people who often do such comparisons.
This isn't a stainless steel and while it will resist rusting stronger than a pure carbon steel such as 1095 or a very low alloy steel such as L6 is has little to no corrosion resistance if exposed to any kind of oxidizing environment. In fact a number of people have complained about getting M4 blades which show significant rusting as-boxed including damage :
Knives used in M4 :
Performance summary :
CPM-3V is a high toughness, high wear resistant air hardening tool steel. It has many uses in industry due to the combination of impact toughness and wear resistance, stamping tools, dies and various blades. Some specification and performance data sheets on 3V from Crucible :
Knives personally used in 3V :
The Ed Schott camp knife was used for a variety of work and the edge held up well, especially considering it was ground at nine degrees per side. It even held up to several dozen full hits from a framing hammer without gross fracture (ref), however it did have problems with a weakness through the tip (ref).
The Extreme Judgement was used to split wood with a baton and the the edge chipped on knots which continued after sharpening. Light impacts on a concerete block (induced further chipping. The Extreme Judgement also deflected through the primary grind on an attempt to cut through a heavy knot. The Heafner Bowie in D2 has almost the same edge profile and was used for the same level of batoning without significant edge damage (ref). The Fehrman is 0.027-0.028" thick at the edge and ground at 15-16 degrees per side, the Heafner is 0.031" thick at the edge and ground at 16-18 degrees per side.
Summary : On paper CPM-3V looks to combine high toughness and wear resistance, however the two knives used did not exhibit such performance.
CPM-10V (AISI A11) is an air hardening very high carbon (2.45%) and high vanadium (9.75%) tool steel designed for exceptional wear resistance and a high hardness. The machinability is very low, in the annealed conditions it is 20% of W1. It is used in industry for molds, dies, and various knives. Some specification and performance data sheets on CPM-10V from various manufacturers :
Knives personally used in CPM-10V :
The utility hunter in CPM-10V was used for a lot of cutting on various materials from cardboard, woods, plastics, hemp and used carpet. It consistently did very well staying sharp a very long time, outlasting many other steels significantly due to a combination of very high hardness and extreme wear resistance : ref. Phil Wilson also does rope cutting with the steels he uses and CPM-10V does very well cutting 3/4" hemp (ref). the blade did not form a patina during any work and it was rarely oiled thus its corrosion resistance is much higher than steels like L6 and O1. The resistance to impact and ductility was not examined but both are seen to be very low from the specificiations. While the machinability of 10V is very low this doesn't influence sharpening time with proper abrasives. The edge profile of the utility hunter was later altered to a 5/10 dual edge which just a few minutes on a x-coarse waterstone to set the bevel. With this profile it cut very well on used carpet, outperforming many other blades (ref).
Summary : CPM-10V makes an excellent choice for a knife which is designed as a cutting tool. It takes a very sharp edge easily and will hold it well for a long tiem resisting wear and deformation very well.
CPM-15V offers even more wear resistance than 10V through a higher carbon (3.4%) and vanadium content (14.5%). It also has a lower machinability and toughness. It is used in industry for molds, dies, and various knives. The data sheet from Crucible :
Knives personally used in CPM-15V :
The Roger Dole folder was compared to several blade in other steels. In general it was not found to have an advantage in push cutting edge retention and in fact was behind a D2 custom. However when compared to an ATS-34 blade it had much better slicing aggression over extended cardboard cutting (ref). While the methods used in that comparison were crude by current standards, the general trends found there regarding wear resistance and hardness have been confirmed by later reviews with much more robust comparisons.
Summary : CPM-15V offers extreme wear resistance and very high hardness and thus makes an excellent choice for a light use cutting knife. The machinability is low which is common for high wear steels so the edge profile should be minimized for ease of sharpening.
Steels discussed :
|20CV||1.9||0.3||20||—||4 / 0.6||1||—||—||0.3||59-62|
Note Phosphorus is normally considered an impurity in steels and limited to under 0.04% in most cutlery stainless, similar tolerances for sulfur, there are also small amounts of copper as well. The composition of ZDP-189 is also of some debate.
H1 is a stainless steel which through a high nickel content 6-8% allows age hardening as opposed to the method of soak/quench/temp commonly used for most cutlery stainless steels. The main advantage of precipitation hardening steels in general is that they can be supplied to a manufacturer in an condition of optimal machinability and then the only heat treatment required is an extended very low temperature soak. This grade has the near immunity to corrosion which has been verified by independent curious individuals. Some users have reported corrosion but it seems to be an issue with contamination. Spyderco's H1 blades have tested in hardness at 58 on the spine for both plain and SpyderEdge versions and 65 HRC on the edge of the plain edge version and 68 HRC on the edge of SpyderEdge model which has been proposed to be due to work hardening Some publically posted materials data on H1 :
Knives personally used in H1 :
A plain edge Pacific Salt in H1 was compared to a S30V and D2 blade slicing used carpet and by adjusting the grit finish of the H1 blade to a more optimal level (rougher) the performance was competitive, showing the importance of edge finish However at the same edge grit finish, the H1 knife had approximately 50% of the sharpness of the S30V blade after 254 slices through used carpet. Comparing the Pacific Salt to a Byrd Meadowlark on cardboad there was no significant difference in slicing edge retention The Pacific Salt was also compared to a Meadowlark in 8C13CrMoV and small Sebenza (S30V) with acute edge profiles slicing up plywood, and the H1 steel held its own to the 8C13CrMoV and both were far ahead of the Sebenza.
The Alantic Salt, which has a SpyderEdge profile, used carpet : out cut a plain edged S30V blade slicing used carpet The Alantic Salt was also used for some very heavy cutting, slicing up a steel belted tire and readily outperformed several plain edged knives in various hard and high wear steels .
Frank k (Bladeforums handle) also compared H1 to VG-10 on cardboard and found a large difference between the plain edged blades, multiples times more material cut with the VG-10 knife for both plain edged blades to have the same level of blunting. However the serrated edges cut for so long it was not possible to determine the superority of either
Summary : H1 is a precipitation hardening stainless steel, extremely resistant to corrosion, fairly tough and ductile for a stainless steel and will tend to deform plastically rather than break when over stressed. The edge holding in cutting abrasive materials like cardboard and used carpet will be low compared to high wear stainless steels like VG-10 and especially S30V however it holds it own with many of the softer and less wear resistant stainless cutlery grades and has much better corrosion resistance.
420J2 stainless is a low carbon martensitic cutlery stainless steel. As the carbon content is well under the amount necessary for maximum martensite hardness (0.6%) the hardness of 420J2 is limited to 54-56 HRC. It is one of the softest cutlery stainless grades and also has a very low wear resistance due to a low carbide fraction. It is the steel most commonly used in fantasy replica weapons and very inexpensive knives because it can be fine blanked readily which reduces need for machining. It is one of the few stainless steels which is so soft it can be machined readily with a file. It is also commonly used as the liner material for folding knives.
Knives personally used in 420J2 :
The Point Guard was used to cut 1/4" thick, double layered cardboard alongside a MEUK in 52100 with an edge hardness of 57/59 HRC, a South Fork in S30V at 60 HRC and a Coyote Meadow in CPM-10V at 62.5 HRC. The edges on the knives were all set to 7/9 degrees per side, and honed freehand on a 600 DMT stone, no microbevel, then cleaned with 3 passes per side on leather loaded with chromium/aluminum oxide, then the same on plain leather and finally again on newsprint. The sharpness was measured cutting light cotton under 200 grams of tension as well as slicing and push cutting newsprint. The Point Guard was outcut many times to one by the other blades and showed a dramtic lowerly performance than S30V which is likely due to the lower wear resistance. However with the edge on the Point Guard left much rougher with the fine side of a cheap hardware store hone, while it will still outcut by the other blades it was compared to, the relative performance was much increased. The low hardness of the steel also means the blade will be much weaker and takes a set fairly readily. With just light tip work in woods the tip took a large and visible set.
Summary : 420J2 is a low carbon martensite stainless, commonly used in fantasy knives and low end cutlery. It is also used as liner material for folding knives. It has a low hardness and wear resistance for a cutlery stainless steel but is fairly tough and very corrosion resistant.
420HC stainless is higher carbon version of AISI 420. It is on the tie line which intersects with 440C and is close to the carbon saturation line at 1050 C and would on average put 0.45:13% C/Cr into the austenite. The hardness is limited to about 58 HRC with oil+cold and a 150C temper. Since it is close to the carbon saturation line when so austenized it will have a low primary carbide volume fraction and relatively high edge stability but low wear resistance. Buck has some comments on 420HC on one of their webpages. Knives personally used in 420HC :
Phil Wilson's Chef's knife was a gift for a friend so it was not extensively used. It was sharpened and it ground easily with minimal burr formation. Wilson has also performed rope cutting testing on 420HC and found it had low extended slicing aggression which is expected given the hardness and carbide fractionvery low edge retention when slicing.
The Buck Zipper was not used extensively though it did show high corrosion resistance and was able to resist rusting even after being left wet for extended periods of time.
Summary : 420HC is a medium carbon martensite stainless which has a corrosion resistance similar to Sandvik 12C27 and but has a lower hardness and wear resistance than 12C27M. It offers similar ease of sharpening and relatively high edge stability due to the low carbide fraction.
The steel used in Swiss Army Knives is referred to as INOX which in general means simply stainless steel. This particular blend has a composition similar to 12C27M having a slightly higher chromium and molybdenum. The Swiss Army knife blades would therefore be expected to have a very minor slightly higher wear and corrosion resistance but lower hardening responce. The upper hardness range for this steel after tempering is about 59/60 HRC but that requires oil and cold treatments and removing each of these will cost 1-2 HRC points which results in the 56 HRC knife blades Victorinox in. Knives used :
The main blade on the Rucksack was used for a rough early comparison slicing cardboard and found to be similar to a Henckles paring knife. It was compared in a more quantitative manner to to a small Sebenza, Calypso Jr. and Meadowlark. The Rucksack showed the least corrosion but was behind small Sebenza in edge retention though the variance in the trials was too high to call the difference statistically significant. The Rucksack was also used to cut used carpet and behind a 10V and 52100 blade but ahead of a LM1 and another softer 52100 blade. The Rucksack was also used to cut free hemp and the performance very interesting as it was ahead of a Mora 2000 and matched a Spyderco Temperance.
Summary : INOX is a stainless steel similar to 12C27M which is optomized for a high toughness and corrosion resistance.
12C27M is a Sandvik stainless steel designed for kitchen cutlery. It lies close to the carbon saturation line at 1100C for C/Cr steels on the tie line which intersects 440B. This means it has a similar ratio of carbon and chromium in the austenite, specifically 0.52 and 14.5 % at 1100C for 440B. It is expected to therefore closely match the the hardness responce and corrosion resistance of 440B and have significantly less less wear resistance and higher edge stability and maximal sharpness through the a lower fraction of undissolved carbides. The maximal hardening responce with oil+cold and a 150C temper is about 60 HRC. It is usually ran at 58 in most production knives. The Data sheet from Sandvik is quite informative. Knives personally used in 12C27mod :
Slicing 3/8" hemp, the Mora 2000 was was not significantly different in extended slicing aggression from a Spyderco Temperance in VG-10 . On a short cutting session on used carpet it was just behind the same Temperance in regards to extended slicing aggression and well in front of another scandinavian styled blade in 1095. On cardboard, for a short cutting run it was not significantly different than the same 1095 blade which shows the difference between comparing short and long term edge retention. The Mora 2000 and 154CM Silver Trident were also used to slice cardboard with both edges at 10 degrees with a 15 degree micro-bevel with a 600 DMT finish. The Mora 2000 had much better extended slicing aggression.
Summary : 12C27mod is mainly used where knives need a very high corrosion resistance and can withstand being used in a dishwasher. It also tends to work well for bushcraft knives because it also offers a high toughness for a stainless steel. It also has a high maximal hardness and edge stability. The wear resistance is however fairly low.
12C27 is a Sandvik stainless upgrades the the hardness and wear of 12C27M at the expense of corrosion resistance and toughness. 12C27 lies very close to the carbon saturation line for C/Cr stainless steels at 1100C on the tie line for C/Cr based stainless steels which intersects 440C. It thus has a similar ratio of carbon and chromium in the austenite, specifically 0.56 and 13.5 % at 1100C. It is thus expected to closely match the the hardness and corrosion resistance of 440C. Since it is to the far left of 440C on the tie line it has a lower fraction of undissolved carbides so it has less wear resistance but a higher edge stability. The data sheet from Sandvik is quite informative. Erasteel also has a pdf data sheet on RWL34 which includes data on PMC27 which is 12C27 by another name.
Summary : 12C27 would work well in knives which don't need the extreme corrosion resistance of 12C27M and are also willing to trade some toughness for a higher hardness and wear resistance.
13C26 is a Sandvik stainless steel with an increased hardness and wear resistance over 12C27 at the expense of corrosion resistance and toughness. It lies on the critical tie line for C/Cr based stainless steels which means the carbon/chromium ratio puts 0.6:12% of carbon:chromium into the austenite at 1100 C to allow maximal as quenched hardness and good corrosion resistance. As it is quite close to the carbon saturation line at 1100 C there is only a small volume fraction of sub micron carbides left undissolved, which have been measured by Dr. Verhoeven at 0.5-1.0 microns.
The Sandvik pdf file on 13C26 contains useful information on the heat treatment and applications. Uddeholm offers the steel as AEB-L. Dr. Verhoeven has studied AEB-L as a knife steel and noted the results in his book on steels for knifemakers. Dr. Landes has also studied AEB-L as in his book on knife steels : Messerklingen und Stahl which is the source of the picture on the right. Note the carbides are slightly larger than noted by Dr. Verhoeven as Landes has used a lower austenization temperature of 1050 C which doesn't dissolve as much primary carbide. Devin Thomas also has given his perspective on AEB-L as a knife steel. Landes has described his heat treating procedure for 13C26 in detail as :
This is a general procedure Landes outlines for martensitic stainless, what changes depending on the steel are the austeniztion temperature and holding time and the tempering temperature.
Summary : 13C26 is a natural upgrade to 12C27 where a higher hardness and wear resistance are required and the higher corrosion resistance and toughness of 12C27 isn't needed. As 13C26 is designed as a razor blade steel it sets a high standard for edge stability and is thus an ideal stainless steel for those who desire a high initial sharpness and keep their blades very sharp.
8C13CrMoV high carbon stainless steel with a a relatively low alloy content. There is a small amount of vanadium for grain refinement and molybdenum for corrosion resistance. With a small amount of vanadium and molybdenum carbides, 8C13CrMoV would have a carbon chromium ratio of 0.75-0.80:13 which puts it very close to the critical tie line for C/Cr stainless steels. Austenite at 1100 C would thus have close to a 0.60:12% carbon:chroimum concentration and a maximal hardening responce with enough free chromium 11/12% for good passivication. It is about twice as far from the carbon saturation line at 1100 C as AEB-L so would be expected to have a significantly larger amount of primary carbides and thus greater wear resistance but lower edge stability. 8C13CrMoV is currently used in the Byrd knives by Spyderco hardened to 61 HRC. Knives personally used :
The Meadowlark was significantly outperformed by a Manix (S30V) in slicing aggression on cardboard but ahead of a Point Guard from CRKT (420J2). The Meadowlark matched the performance of a small Sebenza (S30V) in push cutting sharpness while slicing cardboard but again was significantly behind for slicing aggression. The Meadowlark did match a Pacific Salt (H1) for slicing aggression on cardboard. Slicing used carpet, the Meadowlark was not significantly behind a Paramilitary for slicing aggression. Whittling plywood, The Meadowlark had a slight advantage in edge retention on both the push and slice over a Pacific Salt t and a major advantage over the small Sebenza which had durability problems.
On used carpet the Cara Cara was was comparable in performance to a UK Pen (S30V) and Dozier K2 (D2), and was outperformed significantly by several very hard tool steel blades. However the serrated section was among the top showing the advantage of geometry as well as steel in edge retention. The Cara Cara was also used for some heavy prying in woods where it showed a solid combination of strength and durability. The Finch was compared to a no-name chinese knife on slicing cardboard and showed significantly better extended slicing aggression however the angles were too difference to benchmark the steel.
Summary : 8C13CrMoV is basically an upgrade to 13C26 in terms of wear resistance while reducing edge stability. Thus it offers better extended slicing aggression though lower optimal push cutting sharpness and high sharpness edge retention.
AUS4A is a medium carbon martensitic stainless steel which is on the far left of tie-line which intersects with 440B. Austenized lower at 1050 F it lies close to the carbon saturation line and thus only be a small amount of vanadium primary carbide will remaining with an austenite concentration of 0.40:13.8% of carbon/chromium thus is has a maximal hardness responce of 56/57 HRC after oil+cold and tempering at 150 C. Knives used in AUS4A :
The M16 in AUS-4A was compared on slicing cardboard to another M16 in AUS-8A on the coarse side of a aluminum oxide stone, there was no significant difference between the two knives. It is worthwhile to note that the effect of slicing edge retention is greatly introduced by grit finish as much as steel by comparing that work to similar cutting done on other blades with harder and higher wear steels with a fine grit finish. The M16 in AUS-4A was also compared to a Point Guard in 420J2 and a Temperance in VG-10. The slicing edge retention of the AUS-4A blade fell inbetween 420J2 and VG-10.
Summary : AUS-4A has a slightly lower hardness and wear resistance than 420HC with a slightly higher corrosion resistance thus it is would be best suited to knives with very high demands on toughness and corrosion resistance.
AUS6A is a high carbon martensitic stainless steel the vanadium carbide, about 0.03%, lines on the on the right side of the carbon saturation line for C/Cr based stainless steels at 1100 C. It is on the tie line which intersects 440C which means it has a similar ratio of carbon and chromium in the austenite which at 1100 F is specifically 0.56 and 13.5 % and thus is expected to closely match the the hardening responce and corrosion resistance of 440C while having significantly less less wear resistance through the a lower fraction of undissolved carbides. Knives used in AUS6A :
The Kershaw Vapor did well compared to a Manix in S30V cutting rhubarb due to comparable corrosion resistance however problems with sharpening kept it from being used for comparisions in general.
Summary : AUS-6A increases the carbon content over AUS-4A while keeping the other elements the same and thus increases hardness and wear resistance while reducing corrosion resistance and toughness. It can also be considered to be a high edge stability version of 440C. It actually has a fairly high maximum hardness due to the low chromium content, however due to how it is generally hardened in most production knives it is mostly suitable for a fairly rough utility knife with little regard for cutting performance.
AUS8A is a martensitic stainless steel which is slightly below the tie line which intersects 440C and has an estimated 0.57/13% C/Cr ratio in austenite at 1100C and would thus have a maximum hardness of 62/63 with oil+cold and a 150C temper. Knives personally used in AUS-8A :
The Deerhunter in AUS-8A was outcut by 50% by a VG-10 Deerhunter by about 50% and by about 3:1 by a D2 Deerhunter on 3/8" hemp. However when the influence of corrosion was added by soaking the blades in lemon juice, the AUS-8A blade matched the VG-10 both were far ahead of the D2 blade. For cutting bone, metal and impacted into concrete, the AUS-8A blade was consistently inbetween the VG-10 (low) and D2 (high) blade in regards to durability durability. There was no difference seen in maximum obtainable sharpness at 22 degrees per side and while AUS-8A ground a lot easier than VG-10 and especially D2, this was not an advantage for sharpening time as it tended to blunt more for extended slicing anyway. Another Deerhunter in AUS-8A was compared to two dendritic knives cutting cardboard and found to have similar edge retention in regard to push cutting sharpness but significantly behind in terms of slicing aggression ref. There was no difference noted in ease of sharpness nor initial cutting ability.
The Calypso Jr. was compared to several blades on various materials. A M2 mini-AFCK out cut it significantly on woods due to the thinner profile showing how cutting ability is related more to geometry than steel. The Calypso Jr was well behind D2 (62 HRC), VG-10 (60/62), and CPM-10V (62.5 HRC) for in edge retention on ropes, cardboard and woods.
An interesting aspect was noted with the medium Voyager as the teeth tended to snap readily with overstressed and not deform. The large Voyager was compared to a U2 in SGPS on cardboard, wood and hemp, in all cases the Voyagar was significantly outperformed in regards to edge retention. The largest difference was in regards to slicing aggression which would make sense considering the dramatic difference in carbide type and volume fraction. The Voyager was also subjected to heavy prying loads and showed high strength due to the sabre grind and high ductility, able to take significant bends before it broke. As with most of the softer stainless steels in general, the Voyagar tended to burr readily on ceramic rods and obtaining a crisp edge was problematic.
Summary : AUS-8A falls almost directly inbetween 12C27 and 13C26 in regards to C/Cr composition at 1100C and thus the hardness and corrosion resistance would basically be an intermediate step in that progression. However the carbide volume fraction is much higher so the edge stability is lower while the wear resistance is enhanced. It also related to 8C13CrMoV in a very similar way that 12C27 compares to 13C26. However in general, in most knives it is ran very soft so it tends to function as more of a tough knife than a cutting tool. Benchmade Knives may change the perception of AUS-8A as they are hardening it 60 HRC.
440A is a high carbon air hardening martensitic stainless steel. When austenized at 1100 C the average austenize composition is 0.48:15.1% for C/Cr. This means the maximal hardness with oil+cold and a 150C temper is about 59 HRC. Atlas Steel has a pdf document with some materials info on 440 series steels however it is quite dated as noted in the 440C section. Allegheny Ludlum also has a data sheet on 410, 420, 425mod and 440A stainless steel including materials properties and heat treating information. Knives used in 440A stainless :
The Sog Seal 2000 was compared extensively to a MPK-Ti and found to be similar in edge retention, far more brittle, far less corrosion resistance, and with better resistance to impaction.
Summary : 440A is a stainless steel generally chosen for cutlery which needs high corrosion resistance. It has a higher corrosion resistance than 12C27M and much higher primary carbide fraction and corrosponding increase in wear resistance and decrease in edge stability.
440B is a high carbon air hardening stainless steel which lies on the same tie line for C/Cr stainless steels as 12C27M and puts 0.52:14.5 % of C/Cr into the austenite at 1100C so it has high corrosion resistance and a maximal hardness with oil+cold and a 150C temper of about 60 HRC. It is far to the right of 12C27M so has greater wear resistance with a lower edge stability and toughness. There are not a lot of knives being made in 440B aside from Randall's. Atlas Steel has a pdf document with some materials info on 440 series steels however it is quite dated as noted in the 440C section. Bohler's N685E is a similar steel with a slightly higher carbon and alloy content. There is some mention of it as well in thier overview of stainless including N685 . Knives personally used in 440B :
The Randall #5 in 440B at 56/57 HRC in general compared well to the O1 Randall at 55/56 HRC in regards to tough tasks such as digging in rocky soil where boht knives suffered similar wear/deformation. The 440B Randall also in general better edge retention than the O1 Randall due to the higher hardness and much higher corrosion resistance. When compared to a Spyderco Manix in S30V the 440B Randall #5 was significantly left behind in extended slicing aggression and push cutting sharpness in scraping wood.
Summary :440B has an increased hardness and carbide fraction than 440A and thus offers a higher wear resistance but lower edge stability. It also has a lower corrosion resistance and toughness. It can also be consider to be a high wear resistance upgrade to 12C27M with reduced edge stability and toughness.
440C is a high carbon air hardening stainless steel which is on the tie line for C/Cr based stainless steels which intersects 12C27. It thus has a similar ratio of carbon and chromium in the austenite, specifically 0.56 and 13.5 % at 1100C. It is thus expected to closely match the the hardness and corrosion resistance of 12C27. Since it is to the right on the tie line it has a higher fraction of undissolved carbides so it has more wear resistance but a lower edge stability than 12C27. It also tends to have coarse primary carbides retainted from the solidication process which reduce the ability to take and hold high sharpness for push cutting, Verhoeven mentions this in his book on steels for knifemakers. Buck also found this to be true in their CATRA tests which showed that their 420HC significantly out cut 440C initially and the 440C blade only caught up when both knives were severally blunted. Atlas Steel has a pdf document with some materials info on 440 series steels however it is quite dated for example the following comment ignores the wealth of current alloys which are far harder and more wear resistant than 440C :
Grade 440C is capable of attaining, after heat treatment, the highest strength, hardness and wear resistance of all the stainless alloys.
David Boye's dendritic 440C is 440C used in an as cast state which means the carbides retain their large and extended branching structure. Boye promotes this on the basis of aggressive cutting action such as he has demonstrated with 3000 slices of one inch hemp rope without sharpening. However this dendretic structure is known to be fairly brittle which is why it is usually avoided in steels in general and a more homogenous carbide distribution is preferred which also gives a better responce to hardening. Knives personally used in dendritic 440C :
The Boye hunter in dendritic 440C was compared to the dendritic cobalt version in the kitchen and the steel blade had much better edge retention mainly due to a higher durability which reduced edge damage. The same advantage in edge retention favoring the dendritic 440C over cobalt was seen on half inch hemp. The Boye hunters were also compared to the Deerhunter on cutting cardboard and the sharpness checked for both push and slicing sharpness. In general the performance of the Boye blades was much higher than the Deerhunter in regards to slicing aggression but they were similar in regards to push cutting. All blades including the dendritic 440C blade benefitied from a more coarse finish for better slicing aggression and edge retention.
Summary : 440C has an increased hardness and carbide fraction than 440B and thus offers a higher wear resistance but lower edge stability. 440C can be considered to be a high wear upgrade to 12C27 where a high edge stability isn't desired. However for this purpose, other alloys are generally regarded as superior such as 154CM. Dendritic 440C is focused on extended slicing aggression and as very brittle due to the retained as cast carbides.
154CM is modified 440C, 3 percent of the chromium removed and 3.25% molybdenum added. With a 1100C austenization there is 0.58/10.6/3.4% C/Cr/Mo dissolved. The carbon content suggests a maximum hardness of 62/63 HRC after an oil/cold quench + 150C temper which is confirmed by Crucible's data sheet. Even though there is less chromium, there is a higher volume fraction of chromium carbides vs 440C, specifically 17.5 vs 12 according to the S30V data sheet, though there is no specification of the austenization temperatures which effect this significantly. The molybdenum also forms harder harbides than chromium and increases pitting resistance and gives a strong secondary hardening responce. The lower percentage of chromium also gives a finer carbide size than 440C.
154CM can be tempered both low or high and both give up to 62/63 HRC. The higher temperature is typically used for hot hardness and wear resistance the low one toughness and corrosion resistance. Some knifemakers such as Bob Engnath have argued that the higher temper gives better edge durability, however work by Landes shows that the higher temper reduces edge stability as discussed in Messerklingen und Stahl. ATS-34 is the same steel under a different name made by Hitachi who have published a comparison of the high/low temper. Spyderco has performed Q-FOG and Catra which show VG-10 is superior in both corrosion resistance, initial sharpness and extended slicing aggression than ATS-34. The picture of ATS-34 on the right is from Messerklingen und Stahl.
There are also two powder metallurgy versions of 154CM; CPM-154CM made by Crucible and RWL34 which has 0.2% vanadium to refine the grain and add wear resistance. Knives personally used in 154CM/ATS-34 :
The Buck/Strider Solution was used on some birch hardwood and the edge fractured readily during light chopping. It also chipped out readily during some light digging and cracked in half under a light hammer hit. The Buck/Strider folder did not show the same brittle failure as the Solution however the grinds were so thick a direct comparison was not possible.
The Silver Trident and Mora 2000 in 12C27mod were compared slicing 3/16" cardboard with 10 primary and 15 secondary edges set by a 600 DMT pad. The Mora 2000 had much better extended slicing aggression which is surprising and likely indicates the Trident's steel was defective.
The WB was used for some heavy tip work and able to dig in woods where the tip cracked readily on the TOP's Steel Eagle (1095), however the geometries are dissimilar so a steel contrast isn't possible. The WB was also chopped into a concrete block alongside and took more damage than a 52100 forged bowie from Ray Kirk with more acute edge and the WB took far less damage showing the the extreme difference in impact toughness between the two steels.
The PAB had much better edge durability chopping wood compared to a Machax which chipped out even when the edge profile was more obtuse 26 vs 22 degrees for the PAB. This lead to drastically better edge retention when the profile on the Machax was thinned out so it would have the same level of chopping ability.
The MNK-1 tip was flexed in wood and broke at 15-20 degrees. The Sub-Sniper had signifcantly better edge retention than a Running dog Traditional Tanto in 15n20 (57/58 HRC) carving wood but the much greater grindability of 15n20 allowed similar sharpening times.
Summary : 154CM/ATS-34 is a high carbon stainless steel generally regarded as a direct upgrade to 440C. It has a high wear resistance for a stainless steel and a low edge stability both due to the large carbide fraction with primary carbides as large as 25 microns. It is one of the more brittle stainless steels and in general works best on smaller blades indended for extended aggressive slicing.
VG-10 is a high carbon stainless steel, similar to 154CM with less molybdenum and the addition of cobalt and a small amount of vanadium. The vanadium acts mainly as a grain refiner and the cobalt is promoted to enhance carbide stability (Takefu Speciality Steel webpage on VG-10).
In regards to materials data, spyderco has performed q-fog testing which show VG-10 to be superior to ATS-34/55 in corrosion resistance and CATRA tests which show better initial sharpness and edge retention in CATRA testing and superior to S30V in terms of corrosion resistance but lower in edge retention in extended CATRA testing. Fallkniven has performed break tests on their laminated VG-10 blades which show a higher tensile point for the laminated blades but a lower yield point. So they take a set sooner than pure VG-10 but the laminates will bend further before they break.
VG-10 is an interesting steel and unfortunately it is a Japanese steel and thus direct information on it isn't as accessible as many other steels which are very similar in class aside from the data from Spyderco. However there are some very similar steels for which there is a lot of information. 19C27 for example is a simple steel from Sandvik and it is easy to find not only composition but micro-graphs and detailed hardening directions and even reasoning on design/composition and scope of use:
Sandvik 19C27 is Sandvik's most wear resistant knife steel grade and developed for abrasive applications. Sandvik 19C27 is the odd grade in the Sandvik knife steel portfolio because it's a coarse carbide grade, unlike the other Sandvik knife steel grades.
The coarse carbide grades excel at wear resistance but do not allow keen edge angles and have limited edge stability, due to the sacrifice of toughness related to the coarse microstructure.
Sandvik 19C27 is developed for industrial blades for cutting cardboard and tough fiber materials. The world class wear resistance is the main reason why this grade should be selected. Sandvik 19C27 is limited in corrosion resistance and we recommend surface coating on Sandvik 19C27 for knife applications to avoid corrosion issues.
Now as a point of clarification, estimating properties of one steel from another when many elements change is very difficult, however in this case it isn't impossible because there are many changes which both make the same type of influence and there are no direct contradictory influences :
A micro-graph of 19C27 is shown on the right compared to AEB-L. Note 19C27 has both a larger volume of carbides and much larger primary aggregates up to 15-20 microns in size. This is perfectly consistent with Sandvik's description of it being a coarse steel for cutting abrasive materials more so than retaining a fine cutting edge.
This steel thus isn't designed as a razor blade steel (such as 13C26, AEB-L, 12C27, or the non-stainless steels such as 50100-B, W1, etc.) but is designed for maintaining an aggressive slicing edge and to more strongly resist wear. Other steels in the same class are MBS-26, AUS-8, and 8Cr13MoV.
Now clarity has to be noted in any such statements because they are all relative, 19C27/MBS-26/VG-10 for example has a higher ability to hold a fine cutting edge vs an even higher carbide steel. As with all relative style rankings, the point of views or reference standards are critical.
Knives personally used in VG-10 :
The Spyderco Lum was used for many comparisons and showed a slight disadvantage over S30V at the same angle/grit finish. However these differences are so small that it takes multiple runs averaged with the same angle/grit finish and constraining the cutting to a controlled speed, style of cut and statistical sampling of the material being cut.
If the comparison is not as controlled then those kind of small differences and even much larger ones can be difficult to impossible to spot. Note the image on the right which shows a comparison of the Lum vs three other knives in three different steels :
While the comparison is strictly controlled in terms of edge angle, apex angle and grit finish, type and nature of cutting - the material used was not random sampled and thus due to that one factor alone it takes approximately ten repeated trials for the data to show there is any difference at all between any of the steels.
The Fallkniven A1 took little damage from digging in rocky soil aggressively and was restored to a level of functional sharpness just on the blade of a pick and further on a rock . However much of the durability was due to the heavy edge cross section. The Fallkniven H1 suffered a cracked tip during digging in 2x4's which was surprising as the cross section is very thick. However a replacement did the same work with no issues. The S1 was used to dig in many 2x4 up to the point where the board just cracked in half with no damage and the S1 has a thinner cross section than the H1. When overstressed the Fallkniven F1, S1 and WM all shattered and broke in multiple pieces.
The Fallkniven F1 was significantly behind in extended ege retention than a D2 custom at 62 HRC and well behind a a CPM-10V custom at 62.5 HRC cutting card stock, pine and RS-232 cable, with the sharpness tested cutting cotton, light fabric and slicing rubber. The F1 was also compared in detail to a Spyderco VG-10 blade which was slightly harder and the Spyderco knife showed slighty better edge retention on use car mats but had less durability in chopping wood, cutting copper and impacts from a mild steel rod. The F1 was also compared to a MEUK in Talonite with both having a medium finish (600 grit DMT rod) and had no significant difference in edge retention either in push or slicing aggression after an extended cardboard cutting session. On an extended salt water soak, an F1 in VG-10 was ahead of an F1 in ATS-34 and both were well ahead of the same D2 custom at 62 HRC but well behind a MEUK in Talonite. for an extenesalt water corrosion. Cutting various metals the VG-10 F1 had better edge durability than the ATS-34 version and both had much better durability than the MEUK in Talonite. The VG-10 F1 was also used for some harder metal cutting alongside an Ontario machete where it had significantly lower edge durability cutting thick metals than an Ontario machete.
The D'Allara had some issues with durability concerns with the serrations however they are ground significantly more acute than other Spyderco knives. The Endura saw a lot of work on various media, including a lot of work outside on woods, and various chopping and splitting tasks and generally responded well. The Endura was even harshly blunted by some sod work and sod work and resharpened on a piece of concerete.
The Bill Moran Featherweight was compared to CPM-10V (62.5 HRC), D2 (62 HRC) and AUS-8A (58/59) on cardboard, rope and pine and significantly ahead of AUS-8A in edge retention but behind D2 and CPM-10V). It was also used for work alongside the Fallkniven F1 as noted previously.
The Temperance matching the performance of a Spyderco Military slicing used carpet and also stayed with the Military on cardboard in push cutting sharpness but fell behind significantly in slicing aggression this makes sense considering the similar hardness but much higher wear resistance of the Military in S30V. There was a large difference in grindability noted, removing the same amount of metal from S30V took significantly longer than with VG-10, about two to one. The Temperance was also compared to a Point Guard in 420J2 and M16 in AUS-4A slicing cardboard with an aggressive finish, the Temperance was was distinctly superior to both in slicing edge retention.
The Deerhunter in VG-10 was compared to identical blades in D2 tool steel and AUS-8A stainless steel. In edge retention on hemp rope the D2 blade could cut double the amount of the VG-10 blade before achieving a similar state of significant blunting, and the VG-10 knife 50% more than the AUS-8A. When the influence of corrosion was added by soaking the blades in lemon juice, the D2 blade was far behind the two stainless steels which were similar in edge retention on the hemp. The blade were also used for hard work, batoning, cutting bone and metal and impacted into concrete. The VG-10 blade consistently showed the lowest durability and the D2 the highest.
The Al Mar Sere was used mainly to examine the lock under batoning, the edge was uneffected by impacts which destroyed the liner, however the tang impacted readily even during chopping. The blade required a high force to take a set while prying, however it broke readily under impact from a wooden baton and showed little ability to resist direct impact.
Summary : VG-10 is a high wear stainless steel in the same class as 154CM however has a reduced secondary hardening response.
BG42 is a ball bearing steel which also has very strong hot resistance.
It is basically to 154CM modified
with a significant increase in
vanadium and a small increase in
carbon and chroimum. Due to the ability of vanadium to strongly carbide and the
need to produce a strong secondary hardening, BG-42 is austenized at 1121 C or
2050 F which is much higher than most cutlery stainless steels.
It is also made by Vacuum
Induction Melting/Vacuum Arc Remelting (VIM/VAR) which refines the steel to a
very high purity and thus offers very high fatigue properties. Q-fog tests by
as hardened by Reeve to have superior corrosion resistance to ATS-34/55 and
VG-10. The trade name by Timken for this steel is
Lescalloy. Blades used in BG-42 : The Recondo has a very inefficient grind for a
cutting tool so it was not possible to obtain much information about the ability
of the steel in that regard. The knife could have been reground into a decent
cutting tool but it had severe problems with ergonomics and other aspects. It
did suffer brittle failure fairly easily which is in general to be expected of
that class of steel.
Summary : BG-42 is a very high purity, high wear, martensitic stainless steel
which offers very high heat resistance. The hot hardness is likely not of
significant benefit for knife blades but the other attributes often cause it to
praised among discriminating users. It is generally regarded to be
in the same class as 154CM but better in most respects
for cutlery due to the VIM/VAR process and use of a small amount of vanadium
carbides to reduce the large chromium carbides.
SGPS : main
The Recondo has a very inefficient grind for a cutting tool so it was not possible to obtain much information about the ability of the steel in that regard. The knife could have been reground into a decent cutting tool but it had severe problems with ergonomics and other aspects. It did suffer brittle failure fairly easily which is in general to be expected of that class of steel.
Summary : BG-42 is a very high purity, high wear, martensitic stainless steel which offers very high heat resistance. The hot hardness is likely not of significant benefit for knife blades but the other attributes often cause it to be highly praised among discriminating users. It is generally regarded to be in the same class as 154CM but better in most respects for cutlery due to the VIM/VAR process and use of a small amount of vanadium carbides to reduce the large chromium carbides.
SGPS is a powder metallurgy martensitic stainless steel made by Takefu Speciality Steel. Knives used in SGPS :
The U2 was compared to a had better edge retention slicing cardboard than a large Voyager in AUS-8A, and was even more superior in edge retention slicing unsupported hemp and still better e but to a much smaller degrees push cutting pine. It was also compared extensively to a Jess Horn in ZDP-189 and had better extended slicing aggression on cardboard however the primary angles were too different too alow a comparison of the steels.
Summary : SGPS is a powder metallurgy steel which is in the same class as S30V as a high wear alternative to 154CM.
CPM-S30V is a Particle Metallurgy high carbon, high vanadium stainless steel made by the Crucible Materials Corporation and designed by Dick Barber as a cutlery steel. The prime incentive in its design according to Dick Barber, a metallurgist who worked at Crucible and developed the steel, was to allow heat treating without austenizing temperatures above 1950 F to make it more readily usable by knifemakers as compared to S60V and S90V. S30V is also much easier to grind due to the lower vanadium content compared to S60V/S90V and for the same reason has a lower wear resistance. Materials data on S30V :
Maker information :
Problems with S30V have been frequently reported on internet discussion forums just cutting soft materials such as cardboard, corn stalks, plastics and wood. The frequency of defects is so high that users have reported several defective blades. Sometimes the problems have been solved with sharpening but others have persisted through repeat sharpenings and use. Others have even seen problems with more gross fractures under similar light work. Commonly it is found that S30V blades tend to blunt by chipping at a microscopic level. Direct comparisons have also been done and found that S30V is a small Sebenza in S30V to be less durable than 425mod and an other judges a small Sebenza in S30V comparable AUS-6A. The problems reported with S30V have been argued by representative from Crucible to be due to possible problems due to overheating due to low grindability or issues with heat treatment, ironically these are two of the initially promoted strong points of the steel and a huge effort was made to hype the chipping resistance of the steel which included promoting it hugely in toughness especially hyping the importance of the transverse toughness.
Knives personally used in S30V :
There was little done with the Skirmish and RSK in evaluation because the edges of both would not even sharpen due to the steel fracturing under the hones.
The Green_Beret could only match the edge retention of a Buck 119 in 420HC. Similar in regards to durability both on light metals and on very hard contacts, it was in the same class as the Buck 119.
The small Sebenza had no advantage in push cutting edge retention over a Spyderco Manix also in S30V, a K2 in D2 and a Meadowlark in C13CrMoV. However for slicing aggression edge retention during slicing cardboard the it had a significant advantage over a Meadowlark in C13CrMoV and two Temperancess VG-10 and matched the performance of a Mel Sorg custom in D2. The small Sebenza was also compared to a Pacific Salt in H1, Calypso Jr in ZDP-189, and Meadowlark in C13CrMoV on plywood with all blades at similar edge grinds of six degrees per side. The small Sebenza took significantly more damage in comparison to the other two blades. Similar problems with the edge durability at low angles have been reported on Bladeforums. The corrosion resistance and its effect on slicing edge retention on cutting cardboard was also checked and it was found that a Rucksack had the highest corrosion resistance followed by a small Sebenza then Calypso Jr. and Meadowlark. However even though it rusted the least visibly, the Rucksack was behind the small Sebenza in edge retention, though the variance in the trials was high.
The slicing edge retention of South Fork at 60 HRC (measured by the maker on a HRC testor with the calibration confirmed by comparisons to machines used by Crucible Metals) was compared to several blades used to slice cardboard of several thickness with several edge finishes. The South Fork was out performed by a Coyote Meadow in CPM-10V at 62.5 HRC (hardness measured by the same maker), but significantly out cut a MEUK in 52100 at 57/59 HRC, a BlackJack small in 52100, and was far ahead of a Point Guard in 420J2 stainless at 54/56 HRC. The South Fork was also used to cut plywood and did not see the rapid edge degredation of the small Sebenza for the same work.
The Chinook was used and carried for several weeks and showed significantly better edge retention (many to one) over a plain edged David Boat boat knife. The UK Pen was part of a trial cutting used carpet and it compared well to a K2 in D2 which confirms the behavior seen in the small Sebenza in S30V and several D2 blades. There was little comparitative work done with the Dodo. The very unique blade shape makes direct comparions to other blades very difficult.
The Manix had much better edge retention than a Randall #1 in O1 (55/56 HRC) and another Randall #5 in 440B (56/57 HRC) both slicing cardboard and scraping wood : scraping woods. It also significantly outcut Meadowlark in C13CrMoV and a Point Guard in 420J2 and matched the performance of a small Sebenza on cardboard. In regards to corrosion resistance, cutting rhubarb which is highly acidic, the Manix had similar edge retention as the Randall #5 in 440B (56/57 HRC) and was significantly better than Randall #1 in O1 (55/56 HRC). Since the edge retention was higher in general vs the Randall #5 in 440B (56/57 HRC) on cardboard and woods, it would imply that the corrosion resistance is superior for Randalls 440B as it compensated for the lack of hardness and wear resistance. The Manix was also used for more rhubarb cutting alongside a Kershaw Vapor in AUS-6A and Extrema Ratio Fulcrum in N90 and no significant difference in corrosion resistance was noted, but the edge on the Manix showed less flattening which is likely due to the greater hardness. The Manix also matched the performance of a Paramilitary in S30V on used carpet and both outcut a Heafner custom bowie in D2.
The Paramilitary was used extensively on used carpet and the slicing edge retention was superior to be ahead ahead of a Agent in D2 and significant ahead of a Pacific Salt in H1. It was also compared to a Spyderco Catcherman in MBS-26 and Byrd Meadowlark in 8C13CrMoV and the Paramilitary outlasted both though the differnce was small. As noted earlier with the Manix and Paramilitary were similar on wet used carpet and both outcut a Heafner custom bowie in D2, showing the effect of corrosion resistance.
The Military was used for extensive edge retention work and found to have be comparable to the Temperance in VG-10 on hemp ropes, cardboard and used carpet.
Summary : S30V is a powder metallurgy martensitic stainless steel made by Crucible. It has a high wear resistance which gives it high slicing edge retention on abrasive materials such as cardboard. Frequent problems with edge chipping have been reported frequently on online discussion forums, the performance was inconsistent in the blades used both in regards to edge retention and toughness. The optimal performance see was very high in regards to slicing aggression edge retention on some blades but the performance was not consistent and durability problems were seen with both the small Sebenza and a Green Beret and there were issues with chipping during sharpening with a Benchmade Skirmish and RSK.
Nominal composition of m390 / 20CV :
M390 is a PM steel made by Bohler and is strong promoted as a knife steel :
Third generation powder metal technology. Developed for knife blades requiring good corrosion resistance and very high hardness for excellent wear resistance. Chromium, molybdenum, vanadium, and tungsten are added for excellent sharpness and edge retention. Can be polished to an extremely high finish. Hardens and tempers to 60-62 HRC.
However in industry is it referred to a plastic mold steel and there is a significant body of literature on its material properties. For example it has similar impact toughness as S90V, much lower wear resistance but much higher corrosion resistance C. Kerschenbauer, M.O. Speidel . This combination of properties is why it is valued as a mold steel. However it isn't so clear why it would be preferred over S90V unless there were issues with corrosion in S90V which is a rare complaint.
As to why these properties have that pattern :
The corrosion and wear resistant martensitic tool steels currently used include grades such as CPM S90V, M390, Elmax, Anval 10V-12, HTM X235, for example. Despite the fact that the overall chromium content of some of these alloys is as high as 20 wt. % (e.g., M390), the corrosion resistance is not necessarily as high as one might expect. Depending on the overall chemical composition and the heat treatment parameters, a large amount of chromium, which is a strong carbide former, is pulled out of the matrix and tied up into chromium-rich carbides. This tied up chromium does not contribute toward the corrosion resistance.
One of the practices that has been used to improve the combination of resistance to corrosion and wear, as exemplified by CPM S90V, is to add vanadium. This alloying addition forms hard'vanadium-rich MC primary carbides and ties up a part of the carbon. Due to the fact that the affinity of vanadium toward carbon is higher than that of chromium, the presence of vanadium in tool steels decreases the amount of chromium-rich primary carbides, all other conditions being equal (i.e., the overall chromium and carbon content, the heat treatment parameters, for example).
S90V has a much higher volume of Vanadium carbides which are much smaller than chromium carbides which is why it can optimize a higher combination of toughness, corrosion resistance and abrasion resistance.
Knives personally used in m390 :
Unfortunately that knife came with a heat damaged edge and thus it tended to perform poorly (low ease of sharpening, edge holding and durability) which was likely due to issues with how it was ground.
S90V is a Particle Metallurgy high carbon, high vanadium stainless steel made by the Crucible Materials Corporation. It was called 420V origionally but the name changed to S90V to to negative associations with the 420 group of stainless. Materials data on S90V :
Knives personally used in S90V :
Summary : S90V is a powder metallurgy martensitic stainless steel made by Crucible. It has an extremely high wear resistance which gives it high slicing edge retention on abrasive materials such as cardboard. The downside is the low grindability and it has issues with heat treating as it requires high austenization temperatures.
ZDP-189 is a powder metallurgy stainless steel made by Hitachi Metals of Japan. The actual composition of the steel is unkown publically as Hitachi has described it as 3C20CrMoW, thus the molybdenum and tungsten amounts are unknown. Cowry X is a similar steel made by the Daido Corporation which also has the same carbon and chroimum content but also contains 0.3% vanadium and 1% molybdenum so ZDP-189 may have similar amounts of molybdenum and tungsten raplacing the vanadium as those two have similar effects. While the large amount of primary carbides would seem to suggest issues with sharpness the only problems reported are with sharpening on ceramic rods which can in general cause issues with high hardness steels. In general feedback from user on sharpeness and sharpness is high. Materials data on ZDP-189 :
Promotional material from makers/manufacturers :
Knives personally used in ZDP-189 :
There have been some comments about problems with sharpening of ZDP-189 on ceramic rods, however feedback from user with waterstones typically praising ease of obtaining a high sharpness. Comments have been made about edge damage on ZDP-189 through edge pitting and other reports of corrosion. There have also been some issues with chipping in light cutting but the frequency of reports is very low, especially to S30V.
The ZDP-189 Delica was compared to the VG-10 Delica on slicing 1/8" cardboard through 4 centimeters of edge and found to have significantly better early edge retention and a small advantage in extended use. This was repeated with a 1200 DMT finish on 1/4" cardboard and the ZDP-189 Delica had again significantly better early edge retention and a more significant advantage in extended use. All three Spyderco ZDP-189 blades were compared to multiple S30V blades and the ZDP-189 knives were found to on average cut 57 (8) % more cardboard than the S30V blades before reaching a similar level of blunting.
Summary : ZDP-189 is a powder metallurgy martensitic stainless steel made by Hitachi Metals. ZDP-189 is mainly promoted for the very high hardness 66/67 HRC which is rare in staniless steels.
Talonite is a cobalt super-alloy, it has the same composition as Cobalt 6BH which is further hot roll and age hardened. It is very soft, 42-47 HRC, and has yield and tensile points of 121 and 195 kpsi respectively. For reference Mission's Beta Ti has a yield sterngth of 230 kpsi at 47 HRC and the tensile strength of A2 at 57/58 HRC is 310 kpsi.
Manufacturer data on Talonite from Carbide Processors:
A reference page on Talonite by Marion Poff :
Unfortunately most of the Bladeforums links are broken due to alterations in the way links are archived due to software changes. They can however be retrived with use of the Internet Archive data base.
Knives personally used in Talonite :
The MEUK was compared to ATS-34 and VG-10 (59/60 HRC) F1's from Fallkniven and a D2 custom (62 HRC) from Mel Sorg and the Talonite blade was found to be immune to a strong salt water solution which left the steel blades significantly blunted and required extensive honing to restore : ref. The Talonite MEUK was also compared to several other steel blades on cardboard at three different finishes, polished, medium and coarse. Talonite was able to match the performance of a VG-10 F1 from Fallkniven when both had medium finishes but was vastly outcut by a CPM-10V custom (62.5 HRC,full cryo) with fine polishes and a D2 custom (62 HRC) with a rough finish : ref. The MEUK was also used to cut various metals alongside a VG-10 and ATS-34 F1 and in general it took more damage and took much longer to sharpen : ref.
Summary : Talonite is useful as a blade material when very high corrosion resistance is desired. However the edge retention on cardboard was very low compared to tool steels (D2 and 10V), and the durabiity and sharpening time poor compared to high carbon stainless steels (ATS-34 and VG-10) cutting harder materials. No benefits were seen due to the promoted "lubricity" of talonite nor of its ability to retain aggression after losing a "razor edge", it fared worse than quality steels in that regard. Blunting of course is nonlinear in general so the rate of edge degredation slows down with any blade material with use.
LM1 is an amorphous (no specific crystal structure) alloy of titanium, copper, nickel, zirconium and beryllium. It can be cast to a very precise shape.
This document shows a very low yield strength, 220 ksi, much lower than hardened cutlery steel, and a low hardness, about 50 HRC, and fairly brittle nature. The density is also much lower than steel, 6.3 g/cm^2 vs 7.8-8.1 g.cm^3.
Knives personally used in LM1 :
The model 10 was used for a large variety of work with the edge retention examined on hemp, cardboard, carpet and woods. In all cases it was well behind cutlery steels, even low grade ones, with the edge retention on hemp being just a fraction of a Swiss Army knife (ref) and a regular Olfa knife readily outclassed it on cardboard (ref). The durability was also very low as it chipped out consistently during wood chopping and this was a very light blade (ref). On harder work, light metals, bone and some light impacts on concrete, the LM1 blade was well behind various cutlery steels (ref). In regards to sharpening, there were no significant difficulties associated with this particular material, the only note of interest it that it didn't tend to benefit as much from more coarse finishes as steel blades do, probably because it doesn't have the strength and durability to hold the micro-teeth.
Summary : LM1 is a very corrosion resistant blade material, however it is much softer, weaker and more brittle than even the lower end cutlery steels and thus has much lower edge retention, durability and optimal cutting ability because it needs thicker profiles to gain the necessary durability.
It is critical to realize that titanium like steel has many alloys and the performance changes signficantly among them. Beta-Titanium is a titanium alloy used by Mission Knives which can be hardened to 47 HRC. Some specification and performance data from Mission :
Other materials data :
Knives personally used in Ti :
The Mission MPK-Ti was used significantly alongside various steel knives and there were several distinct differences in performance noted. First was that as the Beta-Ti was softer it could indent more readily. This was a concern for the plain edge on heavy and serrations on moderate as they took visble damage after hitting a seasoned limb. However compared to the current high carbon stainless blades the Beta-Ti can often sustain less damage in really heavy impact work due to the ability to resist fracture. Similar in regards to prying, while it isn't that difficult to give the blade a set compared to cutlery steels it is extremely difficult to push the blade to the point of total fracture and the material has to be basically ripped apart. For most light cutting Beta-Ti tends to have less edge retention than cutlery steels. However on hemp ropes Mission does an excellent job on the serrations which are acute and very coarse and they have excellent slicing edge retention and will outlast many plain edge high end cutlery steels. In regards to sharpening, it had no trouble achieving a razor finish, however it does tend to gum up ceramic stones and be difficult to clean, and it doesn't get the same level of benefit as steel blades do from x-coarse finishes in regards to slicing aggression.
Summary : Mission Knives Beta-Ti is an extremely durable blade material, capable of resisting very high loads before breaking and extreme impacts, it is also near immune to corrosion. It is softer than most cutlery steels so there are issues with edge deformation and edge retention for most light cutting will be low. However the serrations are very acute and very coarse from Mission and will cut hemp, cardboard and other materials for quite some time. As well if the media is very harsh, or there is a lot of chopping or contact with hard materials then the Beta-Ti can do well for edge retention because the chip resistance is very high (ref).
Comments can be emailed to cliffstamp[REMOVE]@cutleryscience.com.
|Last updated :||01 : 10 : 2006|
|Originally written:||01 : 05 : 2006|