Is H1 work hardening a myth?

[Surfingringo]

I've done a lot of sharpening on pe H1 and I've never noticed any increase in hardness or edge retention.

[JD Spydo]

At this point I'm wondering what type of grinding process that Spyderco uses to produce their H-1 Spyderedged ( serrated) blades? The reason I bring it up is because I have another sharpening method that I use on really beat up blades. I have a wet-grinding tool known as the TORMEK which does a very aggressive grinding of metal with the abrasive stone being constantly dipped in water as it's grinding. The wet grinding stone constantly keeps the blade steel cool to protect it from overheating.

But I'm still wondering if the rapid stock removal that the TORMEK is capable of would accomplish the adequate "work hardening" process required to further harden the H-1 blade steel.

I also wish that Cliff Stamp would chime in and explain to us the profound differences between carbon-iron based steels versus Nitrogen based steels like H-1 and LC200N. Because they are two completely different animals all together to say the least.

Hey I'm no metallurgist but there is certainly something in the manufacturing process that makes H-1 the premium blade steel for serrated edges that it has proven to be. I''m also wondering if LC200N would perform just as well in serrated edges? Very interesting thread to say the least.

[bdblue]

Here is an interesting read on that stuff:
https://en.wikipedia.org/wiki/Mangalloy

That's very interesting- it seems that the work hardening provides the high toughness.

[Bushminer]

Suspect the work hardening may happen quicker with a coarser grind initially on the theory that:

- there is deformation (=workhardening) well below the scrape of the grain
- the larger grains would deform to a (proportionally?) greater depth

Maybe able to coment on effect of grinding later. I don't like the sabre grind and take it to not a FFG but an intermediate by "knocking off the edge" with 120 to 400 # carborundum paper. A series of microhardness tests taken across the blade before/after would be interesting.

Awaiting a couple of Ladybugs (PE and Hawkbill) but main delay is getting hold of the mate with the microhardness machine who is away.

[SF Native]

I was thinking about this in a long drive yesterday. There is a lot of good nuggets in this thread. I agree that H1 isn't steel. It might have properties that other alloys don't have. Real testing would have to be done to reveal its properties.
Sal said that compression of the metal will harden it.
I think the edge probably gets more compression from use than sharpening. But you wouldn't notice the hardness until you re-sharpen the edge. It might not be the sharpening that hardens it, but how hard you use it.

[seber]

"H1 is not heat treated. "

My understanding is that H1 is precipitation hardening, also called age hardening. If this is the case then no heat treat would mean a very soft blade. Have I missed something?

[anagarika]

Some BF experienced sharpeners mentioned smooth steel working to work harden medium steel (mid 50 HRC simple stainess or carbon) by smearing the material around apex (trowel effect).

Will the same applied to H1 help work hardens the edge? Anyone tested steeling on smooth glass (i.e. Pyrex)? Perhaps using the corners of SM has similar effect?

Off Topic:
JD, if you use Tormek, check out HeavyHanded's Universal Knife Clamp. Might be useful for you.

[PayneTrain]

I think the edge probably gets more compression from use than sharpening. But you wouldn't notice the hardness until you re-sharpen the edge. It might not be the sharpening that hardens it, but how hard you use it.

Now I'm not entirely sure on this, but I think it isn't actually the amount of stress (compression, tension) put on the material that work hardens it, but the amount that it actually deforms as a result. It's also called strain hardening, and strain is a measure of distance/distance. Atoms have to physically move within the crystal structure. It's a measure of distance that does the work hardening, not just a force. Work = force * distance, so even if there is a force, the work = 0 if the distance moved = 0. And if your edges are being displaced any appreciable amount, your blade is screwed anyway!

But, if it's being displaced into the shape of the blade/edge as in cold working (think a blacksmith beating a blade with a hammer, but instead of being red hot, it's room temperature), then you could get a work hardened knife blade. But I really don't think that any microscopic dislocation that might occur through use or sharpening would be enough to produce further work hardening. But I could be totally wrong!

[sal]

"H1 is not heat treated. "

My understanding is that H1 is precipitation hardening, also called age hardening. If this is the case then no heat treat would mean a very soft blade. Have I missed something?

Hi Seber,

That's why it is in discussion.

sal

[sal]

double tap. sorry.

sal

[Evil D]

Sal I know there are some issues with FFG and H1 in production, but do you know anything about having a blade reground FFG and seeing any hardness increase from it? Do you think that's something you would be interested in testing in house so we have a more "professional" assessment?

[sal]

Hi Evil,

There is some experimenting being done with full flat H1, but production is slow and expensive. We moving on full flat LC in a number of models. Should be out in '17, both folders and fixed blades.

sal

[IR192]

I hope LC200N doesn't make H1 a relic in short order, but if it really is that good I guess it will make great discussions like this one intellectual exercises only. My pac salt, dfly and tasman have both been around the world a few times with me, and I am not ready to hang them up just yet. That being said, after years of personal experience showing that H1 works, I feel less inclined to delve so completely into the depths of "why" it works. But I will happily watch the discussion progress in case anyone ever fully figures it out. :)

[sal]

We believe that H1 is special and is not likely to go anywhere. As new nitrogen steels are developed, as well as older chemistry becoming available, we sill, as always, experiment.

sal

[IR192]

We believe that H1 is special and is not likely to go anywhere. As new nitrogen steels are developed, as well as older chemistry becoming available, we sill, as always, experiment.

sal

Good to hear. Thanks Mr. Glesser.
Regards,
Ed

[Bushminer]

Query re composition, Edge-U-Cation shows C 0.15, Cr 14-16, Mo 2, Ni 0.5-1.5, N 6.0-8.0, P 0.1, Si 0.4, S 3.0-4.0 and W 0.03.

Previous stuff I saw showed N 0.1% which seems to be pretty common on Google, also S at 3.0-4.0 seems high

[Skywalker]

Query re composition, Edge-U-Cation shows C 0.15, Cr 14-16, Mo 2, Ni 0.5-1.5, N 6.0-8.0, P 0.1, Si 0.4, S 3.0-4.0 and W 0.03.

Previous stuff I saw showed N 0.1% which seems to be pretty common on Google, also S at 3.0-4.0 seems high

Which Edge-U-Cation source are you looking at?

The one on the spyderco.com site right now has

Carbon (C) 0.15 / Chromium (Cr) 14.00-16.00 / Cobalt (Co) -- / Niobium (Nb) -- / Copper (Cu) -- / Manganese (Mn) 2.00 / Molybdenum (Mo) .50-1.50 / Nickel (Ni) 6.00-8.00 / Nitrogen (N) 0.10 / Phosphorus (P) 0.04 / Silicon (Si) 3.00-4.50 / Sulphur (S) 0.03 / Tungsten (W) -- / Vanadium (V) --

which agrees with what's in the 2017 catalog and mostly agrees with what zknives has, too.

[ABX2011]

Sal I know there are some issues with FFG and H1 in production, but do you know anything about having a blade reground FFG and seeing any hardness increase from it? Do you think that's something you would be interested in testing in house so we have a more "professional" assessment?

I had a plain edge Pac Salt reground by Big Chris to a high saber flat grind, less than .01 behind the edge. I used it and resharpened multiple times. Edge holding was as poor as when I got it from the factory. Just one anecdotal account.

[Ed Schempp]

Disclaimer: I'm not a metallurgist, but here is a layman perspective of what is happening. I have experimented with nitriding and the forging of Nitrided materials. This is how I perceive the metal and work hardening of Nitrogen steels.
Nitrogen will work as a replacement for Carbon in Martinsite form of steel. In H1 steel it forms the Martinsite under the intense pressure of cold rolling the material. It not only forms bonds interterstically in the crystal but also extraterstally. It will bond crystal to crystal. Nitrogen holds on to one more iron atom than does Carbon. The Martinsite can be formed with 3 iron atoms and the Nitrogen. When deformation occurs the nitrogen can pick up or bond to the other iron atom, in or outside the crystal of Martinsite. Carbon content can increase the number of bonds in the crystal.
The material can change from Fe3CN to Fe4CN to Fe5CN to Fe6CN to Fe7CN. This depends on available Carbon.
This is my perception what is happening. This is perceived from changes in behavior forging Nitrogen steels...Ed

[wrdwrght]

Another anecdote.

My PE Pacific Salt required countless sharpenings when I took down eight substantial ornamental grasses in my garden a few years back.

Make no mistake, this was hard-use. But edge-retention after the latter sharpenings was no better than after the earlier ones.

FWIW, my SE Tasman Salt took down all my many other perennials this Fall without interim sharpenings... Rather than test fate, I now take down my grasses with a hedge trimmer.