H1 Steel - How it Works

[Larrin]

An article about the highly corrosion resistant H1 steel. It's very different than most other knife steels for several reasons, including that the steel is not heat treated by the knife manufacturer. In fact, the steel isn't quenched and tempered like typical knife steel. Learn about how it works instead here: https://knifesteelnerds.com/2019/06/24/ ... -it-works/

[Wartstein]

An article about the highly corrosion resistant H1 steel. It's very different than most other knife steels for several reasons, including that the steel is not heat treated by the knife manufacturer. In fact, the steel isn't quenched and tempered like typical knife steel. Learn about how it works instead here: https://knifesteelnerds.com/2019/06/24/ ... -it-works/

Thanks! Looking forward to reading it as soon as I have time for it... hope there'll be also something about that for me mysterious H1 "work-hardening-thing" in the article...

[Larrin]

Some might argue the article is nothing but the "work-hardening-thing."

[Wartstein]

Some might argue the article is nothing but the "work-hardening-thing."

The more courious I am... Tonight (it's early afternoon where I live) I'll find time to read it.

[Doc Dan]

Thanks, again, for a great article. I see there is still some uncertainties about this steel. No wonder I am confused, a little.

If H1 is soft, that explains the well known toughness, but how do we explain the vaunted edge holding of the serrated blades?

Is it the huge amount of Cr in solution only that leads to such stellar corrosion resistance, or is it that plus Si?

[Larrin]

Thanks, again, for a great article. I see there is still some uncertainties about this steel. No wonder I am confused, a little.

If H1 is soft, that explains the well known toughness, but how do we explain the vaunted edge holding of the serrated blades?

I haven't yet seen the edge retention tests of the serrated blades, so I can't say how good it is right now.

Is it the huge amount of Cr in solution only that leads to such stellar corrosion resistance, or is it that plus Si?

It's the chromium in solution.

[tonijedi]

Thank you for the article Larrin, it made me think about the materials classes I had 18 years ago :D
Do you have and use any H1 blades, PE or SE? Have you tested these steels with your own hands?
I have a SE Salt 2 that I've been using for more than a year and although it serves me well i can't say it has better or worse edge retention than PE H1 or other steels. In fact, it's very difficult for me to evaluate the edge retention as my cutting needs vary greatly. I may cut a lot of stuff one day and have a week or two in between of a similar cutting day.

[Larrin]

Thank you for the article Larrin, it made me think about the materials classes I had 18 years ago :D
Do you have and use any H1 blades, PE or SE? Have you tested these steels with your own hands?
I have a SE Salt 2 that I've been using for more than a year and although it serves me well i can't say it has better or worse edge retention than PE H1 or other steels. In fact, it's very difficult for me to evaluate the edge retention as my cutting needs vary greatly. I may cut a lot of stuff one day and have a week or two in between of a similar cutting day.

I don't own any H1 knives. Serrated edges almost always have much better edge retention than plain edges, by orders of magnitude. The two edge types cut very differently, of course.

[Doc Dan]

Thanks, again, for a great article. I see there is still some uncertainties about this steel. No wonder I am confused, a little.

If H1 is soft, that explains the well known toughness, but how do we explain the vaunted edge holding of the serrated blades?

I haven't yet seen the edge retention tests of the serrated blades, so I can't say how good it is right now.

Is it the huge amount of Cr in solution only that leads to such stellar corrosion resistance, or is it that plus Si?

It's the chromium in solution.

If you had to guess, where is the next break through in knife steel technology going to come from and what will it look like?

[Cambertree]

Thanks for another excellent article, Larrin.

Are you able to expand on the aging process you refer to, which is used after the cold rolling of H1?

Is the steel held at an elevated temperature for a set time, like the tempering process for martensitic steels?

You raise some interesting points about what exactly serrated H1 is compared with, when it is said to have relatively high wear resistance, as measured by a CATRA machine. Other steels in plain edge?

In 'real world' cutting, I think H1 serrated edges roll and bend at the apex a bit more in extended use than they would in a CATRA jig.

It would be interesting to see serrated H1 compared with identically ground serrated blades in martensitic steels like VG-10, and GIN-1.

[Larrin]

If you had to guess, where is the next break through in knife steel technology going to come from and what will it look like?

There are many directions to go in of course, depending on which properties the steel manufacturer would like to emphasize, whether it's hardness, corrosion resistance, edge retention, toughness, ease in sharpening, polishing, etc. I see some opportunities out there for improving the toughness-edge retention balance of stainless steels but I don't know if that necessarily means any of those are coming.

[Larrin]

Are you able to expand on the aging process you refer to, which is used after the cold rolling of H1?

Is the steel held at an elevated temperature for a set time, like the tempering process for martensitic steels?

Yes, it is essentially just a tempering process. I have a whole article on tempering where you can read about all the mechanisms involved.

It would be interesting to see serrated H1 compared with identically ground serrated blades in martensitic steels like VG-10, and GIN-1.

I agree.

[sal]

Hey Larrin,

Give Peter your mailing address and we'll send you some H1 knives to play with.

sal

[Cambertree]

Are you able to expand on the aging process you refer to, which is used after the cold rolling of H1?

Is the steel held at an elevated temperature for a set time, like the tempering process for martensitic steels?

Yes, it is essentially just a tempering process. I have a whole article on tempering where you can read about all the mechanisms involved.

It would be interesting to see serrated H1 compared with identically ground serrated blades in martensitic steels like VG-10, and GIN-1.

I agree.

Thanks! I'll go back and re-read that article.

[Larrin]

Hey Larrin,

Give Peter your mailing address and we'll send you some H1 knives to play with.

sal

Thanks I will contact him.

[elena86]

My brain hurts : " 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."

I am curious to see what Sal has to say about this !!!

[tonijedi]

A question to Larrin and others who may be more accustomed with hardness tests: is it easy to measure the hardness so close to the edge of a blade? If I recall correctly from my student days the surface to test had to be level (90° with the tester). Or maybe this was the case with the machine I used.

[Enactive]

Thanks, Larrin, For sharing another very informative article! I very much appreciate your work.

[Larrin]

A question to Larrin and others who may be more accustomed with hardness tests: is it easy to measure the hardness so close to the edge of a blade? If I recall correctly from my student days the surface to test had to be level (90° with the tester). Or maybe this was the case with the machine I used.

No it isn't easy. Sandvik cross-sectioned the blade to get a flat surface. And with very thin sections microhardness is necessary.

[elena86]

A question to Larrin and others who may be more accustomed with hardness tests: is it easy to measure the hardness so close to the edge of a blade? If I recall correctly from my student days the surface to test had to be level (90° with the tester). Or maybe this was the case with the machine I used.

No it isn't easy. Sandvik cross-sectioned the blade to get a flat surface. And with very thin sections microhardness is necessary.

So, you are saying that Crucible(or Spyderco) misinformed the general public ? ....." It is reported that Crucible metallurgists measured H1 hardness and found it to be approximately 58 Rc at the spine and harder at the edge, approximately 65 Rc "