I Tested the Edge Retention of 48 Steels

No I'm not sure what you are seeing. The most common example of rapid heating would be induction. With induction the behavior is mostly similar just the temperatures are pushed higher. There is a time-temperature balance where a very short time at higher temperature is equivalent to a lower temperature for a longer time.
 
amlimax said:
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Reported. :D
 
Larrin said:
No I'm not sure what you are seeing. The most common example of rapid heating would be induction. With induction the behavior is mostly similar just the temperatures are pushed higher. There is a time-temperature balance where a very short time at higher temperature is equivalent to a lower temperature for a longer time.
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Thanks, Larrin - I don't know what the difference is, but just drove two more chisels up to a higher temperature and quenched and the froze them (thanks to you, I understand that's not just for A2 and completes giving me a wider working range).

At some point, I'll make another larger set of chisels out of 52100 and experiment with this further, swapping the order, etc, to see if the results stay the same. I kind of wondered if it's because a 2 or 3 minute ramp up to heat may be growing the grain a little and making the chisel harder (without being hot long enough to caused retained austenite or really significant growth. It could be any number of things - I'm not looking to blaze new trails, just figure out how to get results where the final temper is comfortably away from chippiness but won't be soft with a chosen temper. "not soft" for a chisel would be something like 61, and if I'm bumping up against the temp where I'd see carbon flux on the surface of the steel (if that's the right terminology), I'm guessing that's more than 200F past nonmagnetic,

The range of useful hardness is greater for knives - chisels and carving tools (not like home depot chisels, but good chisels) generally have to work completely defect free and release a wire edge without much work. 52100 has been a very pleasant surprise - it's almost completely unused in the world of woodworking tools, but chisels need a comfortable combination of strength, toughness and a crisp edge and really nothing to do with abrasion resistance. It's as Ideal as I've seen so far.
 
out of curiosity, is there a general temperature where something like 52100 would make carbon flux dots on the surface? I never do that on purpose, but once in a great while if I get distracted and leave something right under a burner in the forge, there will be flux on the surface and those bits end up hard and polish differently.

A really fantastic toolmaker from colonial williamsburg lit me up a little when I mentioned that I used that as an upper limit for a "quick" forge heat (which is the 2-3 minutes - as fast as I can get there.... "if you see that, you've ruined it!!").

I've seen it on O1 and old files.
 
D-weaver said:
out of curiosity, is there a general temperature where something like 52100 would make carbon flux dots on the surface? I never do that on purpose, but once in a great while if I get distracted and leave something right under a burner in the forge, there will be flux on the surface and those bits end up hard and polish differently.

A really fantastic toolmaker from colonial williamsburg lit me up a little when I mentioned that I used that as an upper limit for a "quick" forge heat (which is the 2-3 minutes - as fast as I can get there.... "if you see that, you've ruined it!!").

I've seen it on O1 and old files.
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No idea
 
sgt1372 said:
I'm not a steel geek and a lot of the info went and still remains over my head but I appreciate the amount of effort that went into this study.

Not to oversimplify the results but, as a layman, this is what I get out of the report, based on the main chart, which compares edge retention (total cards cut - TCC) vs hardness;

The steels with the greatest edge retention ability (that I am most familiar with as a knife collector/buyer), grouped in order from high to low, are:

1) S90V (about 775 TCC) and 10V (which varied from about 725-800 TCC based on hardness from about 59-65)
2) K390/S110V/ZDP189 (about 725 TCC)
3) 204P=M390/20CV (about 625 TCC)
4) S30V (which varied from about 575-625 TCC based on hardness from about 59-64.5)
5) M4/Elmax/S45VN (about 575 TCC)
6) S35VN/Cruwear/CPM4V (about 525 TCC)
7) D2/CPM154/VG10 (about 475 TCC)
8) 440C/14C28N (about 425 TCC); 440C actually varied from about 400-450 TCC based on hardness from about 56-62.
9) LC200N (about 375 TCC)
10) O1 (only about 275 TCC)

What surprised me (just as a knife but not steel geek) was:

1) How much better S90V did than K390/S110V/ZDP189 and M390/20V.
2) How well S30V did and how important the heat treatment was to its performance; still below the "premium steels above" but not far behind for a steel that is often overlooked/maligned (based on what I've read).
3) The fact that M4/Elmax/S45VN did not outperform S30V, even at its lowest hardness level.
4) How poorly LC200N did when compared to the other steels; it obviously it gives up a great deal in edge retention in lieu of corrosion resistance.

What didn't surprise me was how poorly (relatively speaking) that D2/CPM154/VG10/440C and O1 did in the testing. Fortunately, they usually come w/lower priced knives and are easy to sharpened by hand; not so the harder premium steels.

I guess it also shouldn't be a surprise that the degree of edge retention varied directly w/the hardness of the steel but unfortunately the degree of hardness of the steel used in knives often is not provided to potential buyers but, when it is, obviously the hard steel would be preferred, whenever edge retention of the knife is considered important.

This study won't change (all that much) how much importance I place on the steel used when deciding to buy a knife (because as a collector I don't use most of my knives) BUT, where there is a choice to be made, the obvious choice will be to pick the one w/the steel w/better edge retention, especially if it is less expensive than one made w/highly touted/more expensive but yet poorer performing steel.

In this sense, S30V comes out the winner to me for a relatively low cost common steel, especially if you can find it at the highest level of hardness (around 64.5) with an equal edge retention results (about 624 TCC) as compared with M390/20CV, which is also quite surprising and nice to know since I own so many ZTs/Spydercos and other knives that use S30V.

Thanks for this report!
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I really need to order the book ,
but I am afraid it will crush my spirits, as over the years I have invested lots time in vintage gerber, 440c , vasco , D2 , and case cv , cruwear , moraknif , BD1
and basically have shunned S30v as the 8cr made in the USA,even though I have a BM 940-1 in it and can’t see much difference between it and the others
 
The book is good reading. It's worth having and it's not expensive, and it gives you something you can unplug from the phone and internet and read.

Important when you look at the TCC tests, etc, and other discussion about alloying to not get swayed by things you don't love. For example, the first higher carbide knife that I bought was a USA BOS treated Buck knife in 154CM (non powder). It would give up parts of its edge to anything unless buffed. Same with SG2. these are both "better" than stuff like 52100, AEB-L, etc, but if you like to put an edge on a knife and slice and have a fine edge, the latter are a treat.

TCC is just an abrasion test, but I think most users who use a knife and would have to sharpen one often would prefer something simpler. By sharpen, I mean like using a knife in context and getting from dull to sharp in about 90 seconds and getting back to work (for me, that's two bench stones, a deburring wheel and a buffing wheel). Time spent sharpening is proportional to wear rate because it's just a physical process.

I am a woodworker and amateur toolmaker and found Larrin's site interesting, but knew he was dead on the money when I saw his statement that hardness and geometry are more important. In woodworking and carving since we're sharpening all the time, it's very important to spend time learning to sharpen faster and use the tools without damaging an edge. In a 2 hour session in the shop, I may sharpen something five times from completely dull - and then do it the next time, and the next time. The highly alloyed steels are aggravating for woodworking because most have uniformity issues once they begin to wear and then they're very resistant to stones.

Or in short, you like what you like, and reading about something else and being convinced is only temporary. You'll go back to what you like.
 
S-3 ranch said:
I really need to order the book ,
but I am afraid it will crush my spirits, as over the years I have invested lots time in vintage gerber, 440c , vasco , D2 , and case cv , cruwear , moraknif , BD1
and basically have shunned S30v as the 8cr made in the USA,even though I have a BM 940-1 in it and can’t see much difference between it and the others
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FWIW, reading the book made me understand how to get more performance out of the lower end steels I like to use. 440c, K110/D2, BD1N, H1 are some of my faves.
 
There are lots of information to know more about the many types of steel. I really appreciate your contribution and hard work.
 
Fixall said:
It doesn't. Take geometry out of the equation and you'll get a better idea of it's edge retention.
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But most those other steels with a similar amount of rope cuts have either a much higher hardness and/or a higher carbide content if I'm reading it right.
 
LC200N has moderate wear resistance because of the low carbide/nitride volume. When it comes to rope cutting tests on consumer knives you are testing the knife not the steel. There are so many differences with geometry and heat treatment that will often drown out differences of steel.
 
Zeunerite said:
But most those other steels with a similar amount of rope cuts have either a much higher hardness and/or a higher carbide content if I'm reading it right.
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Some steels can achieve higher hardness than others. LC200N only gets up to about 60rc. If you ran all the steels at 60rc, you’d be needlessly leaving a lot of performance on the table with the steels that can achieve the higher hardness…. So it doesn’t really make sense to compare them at the same hardness. Spyderco runs their Mule Team knives at a hardness that they think maximizes the steel so I believe it’s a fair comparison.
 
Larrin said:
LC200N has moderate wear resistance because of the low carbide/nitride volume. When it comes to rope cutting tests on consumer knives you are testing the knife not the steel. There are so many differences with geometry and heat treatment that will often drown out differences of steel.
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That rope cut chart I linked is nothing but Spyderco Mule Team knives so the geometry variable is at least negated. :)
 
My point is that with many people using CATRA to judge edge retention, LC200N does well to keep up with some higher end steels in rope cutting without having to rely on hardness or abrasion resistance.
 
Zeunerite said:
My point is that with many people using CATRA to judge edge retention, LC200N does well to keep up with some higher end steels in rope cutting without having to rely on hardness or abrasion resistance.
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I guess I just don’t really see that on the chart. To be frank though, I really don’t have much faith in any of those rope cut tests because of the amount of variables involved.
 
Fixall said:
That rope cut chart I linked is nothing but Spyderco Mule Team knives so the geometry variable is at least negated. :)
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That would help explain why the LC200N is more in line with expectation on that chart, then, as opposed to whatever knife people keep bringing up as being in line with S30V.
 
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