Work hardening is no myth, it's a phenomenon that has been known about for years and has been formally defined in scientific literature.
The H1 blade in a Spyderco Salt knife is already work-hardened out of the box because it has undergone what is referred to as "cold working" during the production process, which induces the material dislocations necessary for work hardening to occur. The steel is then further hardened via an aging treatment. So a Salt knife with an H1 blade measured at, say, 57–58 Rc (which is what one H1 blade sample was measured at by Sandvik in an independent test) is already in a work-hardened state.
What is a myth is that an H1 blade (or any steel blade for that matter) can be further work hardened by a user through either simple grinding operations or non-permanent, plastic deformation of the material. If anything, excessive grinding can lead to softer or more frangible H1 steel due to overheating.
I think part of this huge misinformation problem in the knife community is the popularity of certain YouTube videos where people talk about work hardening as if it's something that one can induce over time through repeated use and resharpening of a knife. That's not how work hardening happens and betrays a basic misunderstanding of the principle behind it.
Is H1 work hardening a myth?
Re: Is H1 work hardening a myth?
"The Edge is a Ghost". The H-1 edge is a shadow of a Ghost. When Crucible's Barber did micro hardness testing, he said that at the edge, especially in serrated edges, Rc approached 67. He couldn't explain why.
We know when we try to drill a hole, the bit starts to melt about 20 thou in. When we try to mill a ramp for a lock, the bit goes south about 50 thou in.
We've been using H-1 for more than 10 years. Many, including me, love H-1. The OC part of me says why, why why. But then the rational side says there are many things that I don't know why, and still love. (Women are from Venus
).
When I was in school, humans had 48 Chromosomes and the dinosaurs were killed by an ice age. now I learn that we have 46 chromosomes and the dinosaurs were killed by a meteor and became byrds.
Sometimes we have to accept the fact that our tiny brains cannot comprehend the whole. Multiple brains can do better, but are often wrong. Sometimes when you peel back the onion, the center is there, but we just cannot see or understand it. Fortunately, we continue to try. :D
sal
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"Continual improvement is our evolutionary obligation to humankind".
We know when we try to drill a hole, the bit starts to melt about 20 thou in. When we try to mill a ramp for a lock, the bit goes south about 50 thou in.
We've been using H-1 for more than 10 years. Many, including me, love H-1. The OC part of me says why, why why. But then the rational side says there are many things that I don't know why, and still love. (Women are from Venus
).When I was in school, humans had 48 Chromosomes and the dinosaurs were killed by an ice age. now I learn that we have 46 chromosomes and the dinosaurs were killed by a meteor and became byrds.
Sometimes we have to accept the fact that our tiny brains cannot comprehend the whole. Multiple brains can do better, but are often wrong. Sometimes when you peel back the onion, the center is there, but we just cannot see or understand it. Fortunately, we continue to try. :D
sal
---------------------------------------------------------------------------------------------------------------------------------------------
"Continual improvement is our evolutionary obligation to humankind".
Re: Is H1 work hardening a myth?
I cut a wave hook in my first SE Pacific Salt by first drilling a 1/4” hole through the blade just forward of the opening hole. I used a solid carbide twist bit plus oil, and it drilled like butter. That same bit had trouble on a VG-10 Endura doing the same task and I switched to a “Hi-Roc” carbide bit meant for hardened dies. It was still hard going, but a success.
My conclusion was twofold. First, H-1 is pretty soft near the spine of my Pacific Salt and the VG-10 of my Endura is a lot harder. Second, I got lucky not to drill too slowly and experience work hardening. I’ve had that happen drilling type 316 stainless, and it’s no fun at all. The key is to feed the drill steadily and not dwell overlong at one depth.
Sal’s comment about what we don’t understand is very true. There are mysteries galore in a simple knife.
My conclusion was twofold. First, H-1 is pretty soft near the spine of my Pacific Salt and the VG-10 of my Endura is a lot harder. Second, I got lucky not to drill too slowly and experience work hardening. I’ve had that happen drilling type 316 stainless, and it’s no fun at all. The key is to feed the drill steadily and not dwell overlong at one depth.
Sal’s comment about what we don’t understand is very true. There are mysteries galore in a simple knife.
Re: Is H1 work hardening a myth?
"The H1 edge is a shadow of a ghost." I like that. It really sums up the mystery around it.sal wrote: ↑Fri Oct 30, 2020 9:42 pm"The Edge is a Ghost". The H-1 edge is a shadow of a Ghost. When Crucible's Barber did micro hardness testing, he said that at the edge, especially in serrated edges, Rc approached 67. He couldn't explain why.
...
We've been using H-1 for more than 10 years. Many, including me, love H-1. The OC part of me says why, why why. But then the rational side says there are many things that I don't know why, and still love. (Women are from Venus
I love H1, too, and Salt knives are among the most frequent knives I gift to my non-AFI friends and relatives. They're low-maintenance, high-performance cutting tools. Earlier today, I gifted a cousin with a Tasman Salt 2 in SE—she was looking for a small folding knife to use for gardening and I didn't hesitate to offer her my trusty work hawkbill.
But the inconsistent reports about H1 are rather perplexing. There are so many anecdotes of H1 outperforming nominally "longer-wearing" steels, and there are just as many stating the contrary.
My working theory for why there are varied measurements of H1's hardness is that cold working unevenly distributes the martensite in H1. This could possibly help explain why Crucible and Sandvik had wildly divergent Rc findings at the SE edge (67 to 55) but had more-or-less the same Rc measurements (~58) near the blade spine, but there's almost certainly more going on here than just uneven material dislocation.
In addition, there aren't many other stainless steels used in cutlery (as far as I know, at least) that have H1's combination of excellent toughness and reasonably decent hardness. Even if we just go by the ~58 Rc finding that both Crucible and Sandvik observed and disregard their respective 67 Rc and 55 Rc findings as extreme outliers—58 Rc is actually rather high for an austenitic stainless steel, although I guess it would be considered mediocre by more recent high-carbon martensitic stainless "super steel" standards.
I suspect it's this combination of characteristics that partially explains why H1 frequently exceeds expectations (given its chemistry) with regards to practical edge retention. Maybe these attributes are particularly suited to supporting the especially steep bevels and asymmetrical grind of Spyderco's Spyder Edge, especially when it comes to cutting certain materials or performing in a CATRA test.
And finally, there could be some selection bias going on with all the user anecdotes about H1's performance. Think of it this way: most people who buy an H1 Salt knife are probably doing so because corrosion is a real problem in the context where they use a knife... maybe they work in a marine setting or cut materials that readily cause corrosion in conventional cutlery. Naturally, these people will have—perhaps unknowingly—experienced corrosion-induced degradation of cutting performance in their non-H1 knives. Under this specific set of circumstances, it is perhaps not unreasonable to imagine that a serrated H1 knife at 58 Rc can actually have a longer-wearing working edge than, say, a plain-edged CPM-S30V blade at 60 Rc that is slowly being dulled by regular, lengthy exposure to a corrosive environment.
Ultimately, however, all this is just a fun exercise in armchair sciencing on my part. In my everyday life, I'm perfectly happy with the "it just works" explanation :)