Steel Hardness In Production Knives

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I commented:

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It would be interesting to see kinives M390/20CV/204p compared to each other to see how much the HRC changes their edge retention, what is ideal, and what we can expect from a production HT. If M390/20CV/204p is only going to give S30V/S35VN results, it might be better for companies to go with using S90V to get better performance if the can't get M390/20CV/204p to cut better than ELMAX, since M390/20CV/204p have a similar carbide percentage (although different types of carbides) as S90V

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser

Well, Ladies and Gentlemen, our fine friend Super Steel Steve made his own knives to test out of 1084, doing blacksmiths HT and Cryo with dry ice and alcohol. He made a low HRC knife, a high HRC knife, and an un-tempered knife to see if he could get a knife to harden since this was his first go at knifemaking. You should look up the video on his channel, it is not safe for work, and if you are a fan of Apostle P you might not like it. Anyway, what he does show is that his low HRC knife out cut %75 of the production knives he had tested, and the high HRC knife out cut the other %25. Let that sink in for a minute. Everything Roman Landes, Tim Zowada, Kevin Cashen, Darrin and Larrin Thomas, and Cliff Stamp have been saying for years is just proven in this video.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser

[www.youtube.com]




More issues with LionSteel's M390

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser

[www.youtube.com]




"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser

[www.youtube.com]




"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser

[www.youtube.com]




"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser

Apparently GiantMouse (the design collab brand of Jens Anso and Jasper Voxnaes) has shifted their manufacturing partner from Viper of Italy to China's Reate brand, since it seems Viper wasn't keeping up with the quality. A shame to hear, but it might have been related to the issues with Italian M390 that have been popping up (Not only LionSteel had them, there was at least one instance with Steel Will too)

Results of the CATRA Testing:
[drive.google.com]

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser

Except black Spyder that's S30V at 61 Rc, in a range over 60 Rc M390 seems wrong and contradicts the rule of higher Rc better wear resistance, but I think is not!

We have to keep in mind that up some threshold, say 60 Rc, lower Rc freed C to form more carbides, so you have more wear resistance.

CATRA only measure wear resistance with perfect vertical loads without side loads or torsion like we humans do.

This made perfect plausible that after certain threshold lower Rc shows better wear resistance simple because there are more V chromium enriched carbides with much higher hardness than the matrix that resists more to direct wear and not having to face plastic deformation do to lateral loads ( here matrix hardness is important ).

Despite my poor english this make sense to you?

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cabraljr
Except black Spyder that's S30V at 61 Rc, in a range over 60 Rc M390 seems wrong and contradicts the rule of higher Rc better wear resistance, but I think is not!

We have to keep in mind that up some threshold, say 60 Rc, lower Rc freed C to form more carbides, so you have more wear resistance.

CATRA only measure wear resistance with perfect vertical loads without side loads or torsion like we humans do.

This made perfect plausible that after certain threshold lower Rc shows better wear resistance simple because there are more V chromium enriched carbides with much higher hardness than the matrix that resists more to direct wear and not having to face plastic deformation do to lateral loads ( here matrix hardness is important ).

Despite my poor english this make sense to you?

M390 is more wear resistant than S30V due to higher carbide content.

Thanks Larrin, I know that.

What I want to tell is that excluding S30V knife that's not in the same ballpark of the other 3 knives exactly in this aspect ( carbide volume ) the possible explanation for lower Rc knives showing higher performance in CATRA test ( above certain threshold - 60 Rc - ) is more C available from the matrix to form more carbides.

What are you think about this?

Thank you for your prompt response.

Cabraljr,
Sorry, I forgot to add the video where it talks about the misprint of the S30V Spyderco not being M390: [youtu.be]
[www.youtube.com]

There are three things that are trying to be proven with these tests:
1. Higher HRC can contribute to higher edge retention, and can be shown when using the same steel, edge bevel angle, and edge finish
2. M390 at 58-60 HRC performs no better than S30V / S35VN
3. Lions Teel runs their M390 softer than most other manufacturers, thus their M390 does not outperform S30

I think all three were proven correct.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser

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jasonstone20
There are three things that are trying to be proven with these tests:
1. Higher HRC can contribute to higher edge retention, and can be shown when using the same steel, edge bevel angle, and edge finish

That's been shown a million times. Why would anyone argue about it? I've shown data about it in my CATRA articles as well.

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cabraljr
Thanks Larrin, I know that.

What I want to tell is that excluding S30V knife that's not in the same ballpark of the other 3 knives exactly in this aspect ( carbide volume ) the possible explanation for lower Rc knives showing higher performance in CATRA test ( above certain threshold - 60 Rc - ) is more C available from the matrix to form more carbides.

What are you think about this?

Thank you for your prompt response.

M390 has around 15-20% better slicing edge retention than S30V at equivalent hardness. I don't understand the "more C available from the matrix to form carbides" though. Carbon in the matrix contributes to hardness. The remaining carbon is tied up in carbides.

Jason, thanks for explanation.

Hehehehe, I can't express myself in english.

Forget S30V. What I meant is M390 or other high carbon steels at 62 Rc for example, has a given amount of C in the matrix to achieve this hardness. Let's say hypothetically 0.55% C.

At lower hardness, let's say 60 Rc some of that C is no more embedded in the matrix and form more carbides, in other words, lower Rc require less C in the matrix let's say 0.50%, so 0.05% is free to form more carbides and with more carbides more wear resistance.

Thank you again for your patience.

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cabraljr
Hehehehe, I can't express myself in english.

Forget S30V. What I meant is M390 or other high carbon steels at 62 Rc for example, has a given amount of C in the matrix to achieve this hardness. Let's say hypothetically 0.55% C.

At lower hardness, let's say 60 Rc some of that C is no more embedded in the matrix and form more carbides, in other words, lower Rc require less C in the matrix let's say 0.50%, so 0.05% is free to form more carbides and with more carbides more wear resistance.

Thank you again for your patience.

OK that can happen if using a lower austenitizing temperature. However, if tempering down to a lower hardness you get the formation of very tiny tempering carbides that don't really contribute to wear resistance much. When thinking practically the effect of hardness is usually greatest for a given steel. The bigger effect would be composition. For example, using your 0.55% carbon, that leaves 0.9% carbon for carbide formation in S30V vs 1.35% carbon in M390.

It is more likely that two 60 Rc M390 knives having different CATRA performance would be related to:
1) Experimental variability. Running the same experiment multiple times will give a range of results.
2) Small or large differences in edge angle or sharpening.
3) Differences in thickness behind the edge, friction above the edge, etc. between the knives

Larrin, thank you very much for detailed explanation and although I can't write in english I can read quite well and once more I learn from you.

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cabraljr
Larrin, thank you very much for detailed explanation and although I can't write in english I can read quite well and once more I learn from you.

My ability to write in any language other than English is still non-existent so I am completely reliant on the bilingual talents of others.

Larrin,
That's the issue. A few knife makers, knife sellers and knife reviewers challenged that very fact. Some by claiming that a HTC test is difficult for a properly trained person to execute accurately, some claiming that a production HT'd blade is softer or harder at the pivot areas where the testing is mainly done, some claimed that HRC had little or no impact on edge retention, others that none of the cutting tests mattered before because it was cutting done by hand, not CATRA, and still others claiming that M390 is always superior in cutting tests to S30V and S35VN. So Alchemy1/Clint raised the money to have the CATRA testing done, and guess who didn't contribute on dime? That's right, not one of the naysayers.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser

[m.youtube.com]



Updated report:
[drive.google.com]

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser



Edited 1 time(s). Last edit at 09/25/2019 10:21PM by jasonstone20.

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jasonstone20
Larrin,
That's the issue. A few knife makers, knife sellers and knife reviewers challenged that very fact. Some by claiming that a HTC test is difficult for a properly trained person to execute accurately, some claiming that a production HT'd blade is softer or harder at the pivot areas where the testing is mainly done, some claimed that HRC had little or no impact on edge retention, others that none of the cutting tests mattered before because it was cutting done by hand, not CATRA, and still others claiming that M390 is always superior in cutting tests to S30V and S35VN. So Alchemy1/Clint raised the money to have the CATRA testing done, and guess who didn't contribute on dime? That's right, not one of the naysayers.

So many arguments over nothing.

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jasonstone20
Updated report:
[drive.google.com]

Hi,
I find it curious how the recorded tcc is consistently higher than Larrins calculated tcc for 20CV

recorded ( 626.0 + 707.7 + 784.7 )/3 = 706.13333
calculated ( 527.6 + 574.0 + 542.4 )/3 = 548


Also curious the laser goniometer fee is higher than both sharpening and vickers fee

____
Thanks
I don't mow

Quote
ShaperAndMower

Quote
jasonstone20
Updated report:
[drive.google.com]

Hi,
I find it curious how the recorded tcc is consistently higher than Larrins calculated tcc for 20CV

recorded ( 626.0 + 707.7 + 784.7 )/3 = 706.13333
calculated ( 527.6 + 574.0 + 542.4 )/3 = 548

I wouldn't use that equation for tests in other laboratories. It is good for relative comparisons (the trends with steel, hardness, and edge angle are likely extremely similar), but when predicting CATRA values from other testers there are definitely differences. I don't know if that is due to the standard test knives that are thick behind the edge from the dataset I had, or differences in sharpening, testing procedure, different CATRA testers, etc. For example even in my first article where I proposed that equation I showed that it predicted the trend of the Bohler-Uddeholm CATRA results well but the numbers were not the same even when I tried to compensate with edge angle. [knifesteelnerds.com]

Quote
Larrin
I wouldn't use that equation for tests in other laboratories. It is good for relative comparisons (the trends with steel, hardness, and edge angle are likely extremely similar), but when predicting CATRA values from other testers there are definitely differences. I don't know if that is due to the standard test knives that are thick behind the edge from the dataset I had, or differences in sharpening, testing procedure, different CATRA testers, etc. For example even in my first article where I proposed that equation I showed that it predicted the trend of the Bohler-Uddeholm CATRA results well but the numbers were not the same even when I tried to compensate with edge angle. [knifesteelnerds.com]

The average matches up if I
drop every angle 9 degrees
Or increase every HRC by 10
Surely this proves something about the lion HRC Police ?
Here is an equation you shouldnt use it to compare numbers



____
Thanks
I don't mow

[knifesteelnerds.com]

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser

You've put together a great deal of useful information. Thanx Jason. The conclusion that I came to, as a junky, regarding blade steels: "All good just different". I believe most on this forum would agree.

sal

sal,
Thank you. I just wished everyone could be as open minded when it comes to steel. For some reason, edge retention is the desired factor on a knife steel. If you know how to sharpen, edge retention becomes not as important. What frustrates me about this whole issue is in this thread is that people are so quick to attack others for reasons that baffle me. The don't offer any counter evidence, only opinions that benefits them. Most of the work done in this thread has been done a few times before by multiple people. I do find it useful that this type of information gets to reach a larger audience, as their is so much misinformation out their.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser

Quote
jasonstone20
https://knifesteelnerds.com/2019/10/07/catra-tests-of-m390-knives/

Interesting,
not enough blade length for a 40mm stroke so they did a 25mm stroke
... could have asked for 96 cycles...
25mm * 96 = 40mm * 60 = 2400mm

____
Thanks
I don't mow

Running more cycles over a shorter edge would mean that the edge wears more.