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High amounts of vanadium in Steel

Posted by Caraldc 
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High amounts of vanadium in Steel
November 13, 2015 12:11AM
I remember a while ago I read a post by Cliff saying something related to how the Japanese foundries did not like using large amounts of vanadium in the steel they produce. I honestly can’t remember the reason for it but yesterday I came up with my own thoughts. Here's what happened:

I have used ZDP-189 for a while. However, the highest vanadium steel I had used until the day before yesterday had been S30V and Elmax (4% vanadium maximum). I had had the wish to try something with more vanadium such as S90V and S110V for a long time. Well, I got the chance to get my hands on a Spyderco Manix 2 in S110V. I reprofiled the edge to around 15 DPS with a high polish.

Have you noticed how S30V cannot be polished to a true mirror finish? It’s because of the vanadium carbides. Well, while I did not notice a big difference in wear resistance (between S30V and S110V) while grinding the edge (using sand paper), when I got to the polishing final phase of my sharpening…. This was a different story! The hazy glare on S110V was a lot worse than on S30V.

Anyway, I was eager to test the steel and of course, it had to be on cardboard. To make a long story short the knife did not do any better than S30V, Elmax or CTS-XHP.I doubt it was a problem with a burnt edge as I removed quite a bit of material during my sharpening. I used the same cardboard and my intention was to check sharpness after a certain amount of cardboard had been cut (as opposed to taking the knives to their edge retention limits). Same cardboard, same amount cut for each knife.

Well, this is when I concluded that FOR ME, S110V is just is not worth it as I like to keep my knives very sharp as opposed to letting them get really dull before sharpening.

Also, these results reminded me of the Japanese not liking too much vanadium in steel. Over the years I have cut a lot of cardboard with ZDP-189 and my conclusion is that this steel is the one that keeps its razor edge the longest (out of the steels I have tested). So, it seems that while vanadium offers improved wear resistance it does not necessarily translate into better edge holding. In this sense, ZDP-189 holds a razor edge a lot longer than S110V and because of this it is a much better steel FOR ME. Perhaps this is the reason why the Japanese are not very fond of too much vanadium? Simply put, I was really disappointed with S110V’s performance.

Thoughts on this?



Edited 1 time(s). Last edit at 11/13/2015 12:25AM by Caraldc.
Re: High amounts of vanadium in Steel
November 13, 2015 01:12AM
In industry, those steels never were intended to keep sharp cutting edges. It is also why they have made no inroads into the wood working community.

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Re: High amounts of vanadium in Steel
November 13, 2015 02:46PM
So, technically speaking, is ZDP-189 a better steel for cutlery than the high vanadium steels?

Also, is brittleness / chipping problems the reason why the Japanese don't like vanadium in steel?
Re: High amounts of vanadium in Steel
November 13, 2015 03:22PM
I really think it depends on what you are using the knife for, and what attributes you need also, there aren't any 'good' or 'bad' steels, just different, and the ones that fall in the cutlery category depends on the use. Say for a butterknife or spreader knife, anything from bamboo to wood to plastic to 420J steel works fine, and one if the best butter/spreading knives I have used is bamboo, but it has to do with the handle shape and shape of the blade more than what it is made out of. Just my opinion.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
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Re: High amounts of vanadium in Steel
November 13, 2015 03:41PM
While the subject of ZDP-189 is being discussed:

Cliff,

Is there any reason to expect that ZDP would have any significant advantage in terms of apex stability as compared to steels with significant vanadium content?

I'm also more specifically interested in whether ZDP could provide an advantage vs. VG-10 in the following specific use case:

- ~6-8 dps edge bevel, ~0.010" thick edge at 1/32" behind the apex, 15 dps apex micro-bevel
- very high-grit finishes
- light use with little-to-no risk of hard contacts or twisting the blade (e.g. kitchen use against a cutting board, clean cardboard with no staples in it, clam-shell packaging, etc.)
- I'm concerned with edge-retention in the first ~25% of blunting, and could not care less about the bottom 75% of sharpness as I would sharpen well before getting there.

I ask because ZDP is typically run at a very high hardness, and I'm curious about the relative influence of the apex stability vs. the high-hardness of ZDP in light-use at high-sharpness.
Re: High amounts of vanadium in Steel
November 14, 2015 06:29AM
SD,

There are a few point of interest :

-ZDP-189 has a hardness of ~70 HRC

The difference between ZDP and some of these other steels is similar to the hardness difference between the "high end" knives and the "junk" knives, ~10 HRC. It would not be unexpected that very large changes in hardness of ~10 HRC would produce some measure of effect.

-very high vanadium contents

Vanadium carbide is such a hard carbide that it can wear abrasives rapidly and thus could lead to burnishing and fatigue. This would reduce edge retention and apex stability.
Re: High amounts of vanadium in Steel
November 14, 2015 06:44PM
Also, don't forget that Vanadium is toxic to humans. So, if you lick the slurry off you blades like Mark a, you could get sick spinning smiley sticking its tongue out

On a serious note, I would think that knife makers should at consider all the toxins that exist in various blade and handle materials. Vanadium is toxic. G10 and Micarta have toxins. Even wood dust can be harmful.

Even with a respirator you are going to inhale some of these toxins if you are exposed to them all the time.

Just saying that IF I were making knives regularly I would seriously consider using as many non-toxic materials as possible.


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Re: High amounts of vanadium in Steel
November 14, 2015 10:12PM
Quote
CliffStamp
The difference between ZDP and some of these other steels is similar to the hardness difference between the "high end" knives and the "junk" knives, ~10 HRC. It would not be unexpected that very large changes in hardness of ~10 HRC would produce some measure of effect.

So, technically speaking, is ZDP-189 a better steel for cutlery than the high vanadium steels?

Also, is brittleness / chipping problems the reason why the Japanese don't like vanadium in steel?
Re: High amounts of vanadium in Steel
November 18, 2015 01:48AM
Well, this discussion piqued my curiosity enough to pick-up a Spyderco Caly 3.5 in ZDP to play around with. Remind me to send the next knife in this steel or M4 to someone else to thin out the primary grind, because that took more effort than I anticipated.

Sharpening on my SPS-II stones wasn't so bad, however:



I'm curious to see how the ZDP does in terms of high-sharpness edge-retention at very high grit finishes.
Re: High amounts of vanadium in Steel
November 18, 2015 02:18AM
Quote
Caraldc


So, technically speaking, is ZDP-189 a better steel for cutlery than the high vanadium steels?

I think there is an argument there but I don't think it is trivial . Unfortunately modern steels seem to be so dominated by high vanadium steels there is not the wealth of data what would make a very strong argument. Rockstead and few others are using ZDP-189 and unfortunately comparing a $1000 knife to a $100 one isn't going to be common.

Quote


Also, is brittleness / chipping problems the reason why the Japanese don't like vanadium in steel?

No idea. But again, an interesting question.
Re: High amounts of vanadium in Steel
November 18, 2015 03:43PM
Quote
Steel_Drake
Well, this discussion piqued my curiosity enough to pick-up a Spyderco Caly 3.5 in ZDP to play around with.
I'm curious to see how the ZDP does in terms of high-sharpness edge-retention at very high grit finishes.

This is a nice knife indeed. I have it and have used it over the years. Here are my observations:

- The 420J2 portion of the blade will get scratched even if you look at it funny.
- The ZDP-189 holds a razor edge for a while and it isn’t chippy, it seems to wear smooth on cardboard like a low carbide steel (I find S30V to be a lot more chippy).
- I had a Spyderco Michael Walker (also in ZDP) Rockwell tested and it came out at 65 RC.
- Even though the steel is very hard, it takes a very nice mirror polish (much better than S30V as there are no vanadium carbides).
- Touching up the edge on ceramic is not that easy.

Let us know your impressions once you get the chance to test the knife.
Re: High amounts of vanadium in Steel
November 18, 2015 04:36PM
Quote
Caraldc
So, technically speaking, is ZDP-189 a better steel for cutlery than the high vanadium steels?
from the research I have done, zdp is another low volume, high purity steel made by HItachi aimed at the cutlery market. as with the white and blue series high carbon steels, hitachi makes a low volume that it can sell for premimum prices. because of the high prices of zdp, most knives will probably be a sliver of zdp clad in softer stainless.
as has been noted several times before, the CPM "V" series steels were developed for the plastic, ceramic, food, and medical applications where high hardness and wear resistance were required. some interesting reading here,especially how they are testing toughness and wear resistance. [www.google.com]

Quote
Caraldc
Also, is brittleness / chipping problems the reason why the Japanese don't like vanadium in steel?

for whatever reason, the Japanese steels you hear the most about are from Hitachi, the ones we have heard about the most are the blue and white high carbon steels. hitachi is very private with the exact details of this steel other than to say it is made using similar methods to those 100 years ago. and don't forget the collecting of high iron sand(to use for the basic steel) from an unknown bay so rich in iron it can be collected with a magnet. hitachi does use vanadium in its high speed CPM steels and in Aogami Blue Super.
Re: High amounts of vanadium in Steel
November 18, 2015 05:22PM
Carldc,

Considering that I thinned down the primary and left it with a 240-grit finish, I'm not too worried about the 420J scratching.

While the ZDP was a bear to thin out the primary on, it hasn't been any more difficult or time consuming to achieve a mirror polish on the edge bevel using my Sigma Power Select-II stones (not unexpected as they are designed to cut HSS quickly), and was no more difficult to apex micro-bevel with my Spyderco fine rods. The resulting push-cutting sharpness was at least as high as any of my high apex-stability steels (Aogami Super, 52100, 1095), but it remains to be seen how this knife will respond to touch-ups.
Re: High amounts of vanadium in Steel
November 18, 2015 05:57PM
I think that when talking about mirror polishes and cutlery steels, two perspectives should be accounted for.
  1. Knife makers that are applying a mirror polish to the primary blade grind
  2. Knife sharpeners who are applying a mirror edge to the edge bevel

I think that applying a mirror edge to the bevel only, which is not subject to close cosmetic scrutiny usually, can be done with 'hard to polish' steels, while applying a cosmetic mirror polish to the primary grind can be a who different thing.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
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Re: High amounts of vanadium in Steel
November 18, 2015 10:22PM
Jason,

This is a good point. There is a world of difference between the kind of mirror you can get freehand on an edge bevel and what it would take to get a true cosmetic mirror on an edge-bevel, much less on an entire primary grind.

What I've noticed is that on 'hard to polish' steels it is only the bottom little bit of edge-bevel height above the apex that gets the kind of mirror polish the whole edge-bevel will get on 'easy to polish' steels. I'm fine with that as it is the grit finish of the apex which has the largest influence on the resulting push-cutting sharpness once it is apexed.