Rockwell Hardness

R

Rhodies

Joined
Jul 27, 2017
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Looking for a website that lists the hardness of the different blade steels. I have done searches and have come up with a slew of sites that will list the makeup of the particular Blade Steels along with their attributes but no mention of specific hardness?
 
Look at the datasheets from the manufacturer of each blade steel. Each steel has a range not a specified exact hrc. It's up to the heat treatment to determine what the hrc will end up at.
 
Benchmade is one of the few manufacturers that list blade hardness. If it is listed, it will usually be in a 3 point range, for instance
Blade Steel: CPM-S30V (58-60 HRC)
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Also, if it is listed, I see it in BladeHQ's listing, which makes it easy to look up.
 
jpm2 said:
Benchmade is one of the few manufacturers that list blade hardness. If it is listed, it will usually be in a 3 point range, for instance
.
Also, if it is listed, I see it in BladeHQ's listing, which makes it easy to look up.
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I checked out BM Site and they do list a lot of the RC ratings. Go to Spyderco's website and nada, which was kind of disappointing. I checked out Hitachi Steel to see if their ATS-55 was listed and again, nada... You truly have to do some digging which I am doing now. Even BladeHQ is hit and miss but I keep plugging away. As near as I can tell, this is what I have found to be pretty accurate:

CPM-M4 is rated @ 62-64
ATS-55 is rated @ 58-60
420HC is rated @ 54-56
VG-10 is rated @ 57-59 (Be willing to bet Spyderco Pushes hardness to 59)
 
jpm2 said:
Just remember that 3 manufacterers can use cpm-m4 and each one might use a different heat treatment that might result in a different range of hardness.
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Yes, but this is the best I could come up with at this time, it at least gets me in the neighborhood. Just like to know what I'm up against when choosing sharpening stones for different metals whether it be a softer or harder metal e.g. Aluminum Oxide or Diamond/SiC Stones.
 
When selecting sharpening media, you need to also take into account carbide content of the blade, and type of carbide.
 
Rhodies said:
Yes, but this is the best I could come up with at this time, it at least gets me in the neighborhood. Just like to know what I'm up against when choosing sharpening stones for different metals whether it be a softer or harder metal e.g. Aluminum Oxide or Diamond/SiC Stones.
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Hardness has little to do with sharpening, it's carbide size that dictates what sharpening media to use.
 
Rhodies said:
Yes, but this is the best I could come up with at this time, it at least gets me in the neighborhood. Just like to know what I'm up against when choosing sharpening stones for different metals whether it be a softer or harder metal e.g. Aluminum Oxide or Diamond/SiC Stones.
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The Rockwell (RC) hardness of the blade isn't really going to make a lot of difference, in terms of telling you which type of stone will do best. It's nearly all about the carbides in the steel, for which the RC numbers don't apply anyway (Rockwell testing doesn't test the hardness of the carbides). The carbides will be much, much harder than the rated HRC value for the steel itself. Select your stones based on the steel's vanadium carbide, chromium carbide, tungsten carbide content. That's also where the steel mfr's data sheets can come in handy; some of them will provide additional info about wear resistance, which is determined by the carbide types, and amounts of them, in the steel. The wear resistance, as determined by carbide content, is what will impact sharpening the most.

RC hardness will only matter (maybe) if you're thinking of using natural stones (Arkansas) for sharpening. Some super-hard steels in the HRC 60s range might be noticeably more challenging on such stones, OR impossible, if they also contain a lot of vanadium or chromium carbides and other types of hard carbides. A very hard, simple carbon steel blade, like 1095 at 60+ HRC would be OK on natural stones, because 1095 has no hard carbide content. But, something like 440C, D2 or S30V at lower hardness (HRC 58, for example) will be troublesome on Arkansas stones, due to their hard carbide content. Those are the differences that'll matter.

Synthetic stones in aluminum oxide or silicon carbide will handle a lot of steels. Diamond or CBN options will generally work better, especially in refining stages, for steels very heavy in vanadium carbides (think of S30V and beyond, for example).


David
 
Obsessed with Edges said:
The Rockwell (RC) hardness of the blade isn't really going to make a lot of difference, in terms of telling you which type of stone will do best. It's nearly all about the carbides in the steel, for which the RC numbers don't apply anyway (Rockwell testing doesn't test the hardness of the carbides). The carbides will be much, much harder than the rated HRC value for the steel itself. Select your stones based on the steel's vanadium carbide, chromium carbide, tungsten carbide content. That's also where the steel mfr's data sheets can come in handy; some of them will provide additional info about wear resistance, which is determined by the carbide types, and amounts of them, in the steel. The wear resistance, as determined by carbide content, is what will impact sharpening the most.

RC hardness will only matter (maybe) if you're thinking of using natural stones (Arkansas) for sharpening. Some super-hard steels in the HRC 60s range might be noticeably more challenging on such stones, OR impossible, if they also contain a lot of vanadium or chromium carbides and other types of hard carbides. A very hard, simple carbon steel blade, like 1095 at 60+ HRC would be OK on natural stones, because 1095 has no hard carbide content. But, something like 440C, D2 or S30V at lower hardness (HRC 58, for example) will be troublesome on Arkansas stones, due to their hard carbide content. Those are the differences that'll matter.

Synthetic stones in aluminum oxide or silicon carbide will handle a lot of steels. Diamond or CBN options will generally work better, especially in refining stages, for steels very heavy in vanadium carbides (think of S30V and beyond, for example).


David
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Thanks David, there appears that there is a lot to learn. Here all along I thought that Hardness was to determine what abrasive medium to use.
 
I have to disagree that hardness doesn't affect sharpening.
I can sharpen my old case cv blades with naturals fairly quick. New GEC's in 1095 are noticably slower. 52100 and W2 nearing mid 60's requires me to pack a lunch.
 
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jpm2 said:
I have to disagree that hardness doesn't affect sharpening.
I can sharpen my old case cv blades with naturals fairly quick. New GEC's in 1095 are noticably slower. 52100 and W2 nearing mid 60's will require you to pack a lunch.
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For myself, I just said as compared to the hardness of the carbides (the least of which will be 2+ times as hard as the steel itself), and the abrasive chosen to grind them, the HRC ratings won't be as much an obstacle for most stones, as compared to carbide-heavy steels at most any hardness.

Most of the issues that've slowed me down with simple steels (Case CV & Tru-Sharp stainless, Schrade 1095, for example) have come from very thick grinds (biggest problem; includes very heavy blades like chisels and plane irons with wide bevels especially) and/or lots of softish, gummy low-alloy stainless steel to remove, which clogs the hones and brings them to a halt. But if the grinds are thin, even Schrade's old 1095 (which was treated up to low-60s HRC at times) is still easy, even on Arkansas stones. That's because it's 1095, which literally has nothing in it (chromium, tungsten, vanadium) to form very hard carbides, AND because it was hard enough to minimize clogging issues on the stones, and hard enough to minimize troubles with burr-removal as well. Their 1095 at RC ~ 60 has been one of the easiest steels I've ever sharpened, in fact.


David
 
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