H-2 Steel, Knife Steel Nerds Article is Out

[Deadboxhero]

My understanding is that grinding introduces stress / micro fractures / dislocations that increase the strength and thus hardness (BBB will correct me if I got it wrong). This actually also happens with other steels and is part of the reason for cold forging (though I am not sure how much actual effect does it have)

While strain can lead to increased dislocations which can increase localized hardness some, I believe in past discussions the hypothesis is that the increase in hardness for serrated H1 was believed to be an increase in the work hardening feature by the more aggressive grinding of serrations causing deformation induced transformation of any remaining austenite at the edge.

It was rather exciting to read Dr Larrin's articles discussing this further since it is rather complex to understand without a background in the subject.

It would be interesting to look at the edges with metallography and see if there is an observable difference in the microstructure at the edge for the sake of curiosity.

It is quite curious how austenite converts to martensite with deformation and given how thin the cross section of an edge it would be interesting to look at it more.

When I first read that H1 article I was surprised to see so much soft delta ferrite in the microstructure from the Sandvik micrograph that Larrin shared.

Upon first observation I thought they were chromium carbides until Larrin pointed out there is basically no chromium carbide and it has to be delta ferrite.

Thats why its nice having Doc around, he can wash off the mud and make things more clear when mucked up in competing details.

[Deadboxhero]

I know this is one of Vivi's many favorite steels, any thoughts Vivi on H2 after reading the article?

I felt like it was a good break down of what we all expect from H2. I'll be watching his site when H2 becomes available. He never seemed to cover H1 much so hopefully when H2 comes out we can get more data on it.

I don't expect H2 to perform drastically different.

I thought it was interesting how close H1's composition is to pot metal

Either way I have enough H1 pocket knives to last me, my kids and my eventual grandkids!

To get more data being able to get the steel in bar stock is crucial so that it can be processed into the correct dimensions charpy specimens and catra blades.

There were also people asking for more information/data about how 8Cr13MoV compares to all the other steels which is a good question given its abundance, this also requires getting the steel in bar stock to get more data and these steels arent very available for direct sale of a small pieces.

It will be interesting to see your take on H2 since you have gotten a good feel for H1 over the years.

[Wartstein]

.... I'll admit to having not tried H1, but I do not get into extreme saltwater environments so have not really been motivated to give it a try.

You definitely should!

I don't need that high level of corrosion resistance too, but serrated H1 has always been awsome in my use! It is as good as they say, stays sharp enough forever.

Can't say anything 'bout H1 in PE, never tried, but probably should with a "Vivi edge " (or the "vivi-est" edge I can achieve with my limited sharpening skills and gear)

[p_atrick]

When Gail and I…

Sal, you mention Gail quite a bit in your talking stories. Yet, today, most people think of you and Eric when they talk about Spyderco. What role did she play in the birth and growth of the company?

[wrdwrght]

According to Dr. Larrin’s article on H1, he states that Sandvik could not duplicate the results that Crucible achieved. Quoted below.

“I was sent an analysis of H1 in a Spyderco Salt by Sandvik. They did not find an increase in hardness at the edge, in fact they found a decrease. The plot below is what I was sent, where the value at about 55 Rc was 0.4 mm (0.16″) from the edge. Unfortunately I was not provided an x-asis to see the distances between the measurements. However, the ~57 Rc of the steel is comparable to the value reported above from Crucible. It may be that the hardness was reduced at the edge due to overtempering as a result of grinding.”

Yeah, I saw that. It’s why I voiced concern above about whether the experiment Sal mentions was actually redone.

Seems not (no x-axis). Thus the findings of Cruwear’s Crucible’s (!) metallurgist were not properly falsified.

By properly, I mean scientifically. What we are left with is a variance in the act of measurement.

[JRinFL]

According to Dr. Larrin’s article on H1, he states that Sandvik could not duplicate the results that Crucible achieved. Quoted below.

“I was sent an analysis of H1 in a Spyderco Salt by Sandvik. They did not find an increase in hardness at the edge, in fact they found a decrease. The plot below is what I was sent, where the value at about 55 Rc was 0.4 mm (0.16″) from the edge. Unfortunately I was not provided an x-asis to see the distances between the measurements. However, the ~57 Rc of the steel is comparable to the value reported above from Crucible. It may be that the hardness was reduced at the edge due to overtempering as a result of grinding.”

Yeah, I saw that. It’s why I voiced concern above about whether the experiment Sal mentions was actually redone.

Seems not (no x-axis). Thus the findings of Cruwear’s metallurgist were not properly falsified.

By properly, I mean scientifically. What we are left with is a variance in the act of measurement.

I appreciate the differentiation. Without knowing details of how each test was performed we are left with what you say.

Based on Dr. Larrin's analysis and my own limited use, I will still err on the side that there is no increased hardness on SE H1 edges.

[sal]

When Gail and I…

Sal, you mention Gail quite a bit in your talking stories. Yet, today, most people think of you and Eric when they talk about Spyderco. What role did she play in the birth and growth of the company?

Hi P_atrick,

Interesting question. Gail is a 50% owner in Spyderco. She has been there from Day One. She has been involved in every model, every project and she was also involved in the manufacturing of everything we made from the Portable Hand to the knives. She still works every day, though technically, she is retired, as am I. Without Gail, there would not have been a Spyderco.

sal

[Manixguy@1994]

I think if I am correct Gail may be a lefty too besides being a wonderful person . MG2

[jwbnyc]

Leftiez Rool.

[Gtscotty]

According to Dr. Larrin’s article on H1, he states that Sandvik could not duplicate the results that Crucible achieved. Quoted below.

“I was sent an analysis of H1 in a Spyderco Salt by Sandvik. They did not find an increase in hardness at the edge, in fact they found a decrease. The plot below is what I was sent, where the value at about 55 Rc was 0.4 mm (0.16″) from the edge. Unfortunately I was not provided an x-asis to see the distances between the measurements. However, the ~57 Rc of the steel is comparable to the value reported above from Crucible. It may be that the hardness was reduced at the edge due to overtempering as a result of grinding.”

Yeah, I saw that. It’s why I voiced concern above about whether the experiment Sal mentions was actually redone.

Seems not (no x-axis). Thus the findings of Cruwear’s metallurgist were not properly falsified.

By properly, I mean scientifically. What we are left with is a variance in the act of measurement.

I appreciate the differentiation. Without knowing details of how each test was performed we are left with what you say.

Based on Dr. Larrin's analysis and my own limited use, I will still err on the side that there is no increased hardness on SE H1 edges.

Same, as far as I've seen we have even less information on Crucible's investigation than Sandvik's, so, not much to allege a reproducible test either way, and that probably wasn't the intention anyway.

My takeaway is that my relatively poor edge holding experience with PE H1 is probably not an anomaly, and that most of the magic we see ascribed to H1 is probably due to the effect of good serrations and the fact that it can support especially acute geometries without chipping.

[Wandering_About]

.... I'll admit to having not tried H1, but I do not get into extreme saltwater environments so have not really been motivated to give it a try.

You definitely should!

I don't need that high level of corrosion resistance too, but serrated H1 has always been awsome in my use! It is as good as they say, stays sharp enough forever.

Can't say anything 'bout H1 in PE, never tried, but probably should with a "Vivi edge " (or the "vivi-est" edge I can achieve with my limited sharpening skills and gear)

Maybe someday! I should grab an H1 knife while they are still available, just for fun.

Edit to add: I caved and ordered a pacific salt 2. Figured I should just do it instead of just thinking about it.

[Spyrosgeo]

I would like to know when the release date of the first h2 salt series knives would be!!

[Michael Janich]

Dear Spyrosgeo:

Welcome to the Spyderco Forum.

Stay safe,

Mike

[Blayd]

Thinking that the perceived superior 'hardness' of serrated H1/H2 blades is not actual work hardening, but more a function of the serrated blade geometry. Multiple sharp edges mechanically supported by the tines on both sides of the edges vs one continuous edge not supported and different in geometry than the serrated sharp edges. Rolling an edge in the serrations is difficult to do, while more likely with the plain edge due to lack of mechanical support and geometry vs a serrated edge...

[phaust]

Thinking that the perceived superior 'hardness' of serrated H1/H2 blades is not actual work hardening, but more a function of the serrated blade geometry.

Supposing that's the case, it still comes back to what's special about H1/H2 versus other steels because the delta between serrated and plain edge is significantly higher than with other steels. If it was solely geometry, we'd see similar deltas.

[James Y]

vivi has had excellent edge-holding results with PE H1, with his method of sharpening it. Maybe he will mention that here. I would be curious if he can get the same results with PE H2. I'm betting yes.

Jim

[Red Leader]

Thinking that the perceived superior 'hardness' of serrated H1/H2 blades is not actual work hardening, but more a function of the serrated blade geometry.

Supposing that's the case, it still comes back to what's special about H1/H2 versus other steels because the delta between serrated and plain edge is significantly higher than with other steels. If it was solely geometry, we'd see similar deltas.

This is where my brain was taking it as well. If it is all about geometry, then certainly an Enuff 2 in K390 would be the longest edge holding device known to man. I believe there are still questions around Spyderco’s assertions that SE H1 is the best edge retention they have measured. Because maybe something like SE K390 hasn’t been tested…maybe because there was never a question or need to. I would still like to see hard numbers on SE H1 and if other SE knives have also been tested, what those numbers are as well.

Probably the only way we’ll see all this put to bed is a head-to-head comparison between 4 knives:


SE H1
PE H1
SE High wear resistance tool steel
PR High wear resistance tool steel

…and then do the testing on all 4 and compare results. I would be looking for a comparison between the SE/PE for each steel and how much longer, in percentages, the SE lasted against each comparitive steel’s plain edge sibling, and then of course just the raw numbers - how many cuts could each one make, period?

Maybe it would tell us there is something special about SE H1, or maybe that it would tell us that while SE in H1 is indeed excellent, it is still outclassed by SE in tool steel with better baseline edge retention.

I for one would love to know.

[cabfrank]

It's a test anyone could do. I might be curious about the difference in the serrated edges, but it would just be curiosity. H1 SE has great edge retention and other great characteristics, so I would still favor it.

[TimButterfield]

...
Probably the only way we’ll see all this put to bed is a head-to-head comparison between 4 knives:


SE H1
PE H1
SE High wear resistance tool steel
PR High wear resistance tool steel

…and then do the testing on all 4 and compare results. I would be looking for a comparison between the SE/PE for each steel and how much longer, in percentages, the SE lasted against each comparitive steel’s plain edge sibling, and then of course just the raw numbers - how many cuts could each one make, period?

Maybe it would tell us there is something special about SE H1, or maybe that it would tell us that while SE in H1 is indeed excellent, it is still outclassed by SE in tool steel with better baseline edge retention.

I for one would love to know.

But, ...

How would these PE variants be sharpened? Would it be to a high-grit finish or even honed or would it be toothy sharp with only a low grit used? Would any of that make a difference?

For the results to be definitive, they may also need to be thorough. Sorry.

[cabfrank]

Absolutely. That is why the chasing of some of these these definitive answers is futile. Not everyone's uses and experiences are the same, and there are a tremendous amount of variables.