stainless san mai

kybruce, where are you located? Your profile doesn't have any info. Filling it out helps folks know the area you're in and able to offer more help to you.

Are you talking about using SS for the outside cladding with a high carbon steel for core so the outside is shiny with a dark core? Something like this folder I've started?:
Slip-Joint.jpg


That is 416SS cladding with 1095 core. The bright stripe between core and cladding is a thin layer of pure nickel. There are several folks around who do SS San Mai. I like it better than using carbon on both places, but is a tad tricky to make.
 
KenH said:
kybruce, where are you located? Your profile doesn't have any info. Filling it out helps folks know the area you're in and able to offer more help to you.

Are you talking about using SS for the outside cladding with a high carbon steel for core so the outside is shiny with a dark core? Something like this folder I've started?:
Slip-Joint.jpg


That is 416SS cladding with 1095 core. There are several folks around who do SS San Mai. I like it better than using carbon on both places, but is a tad tricky to make.
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I think he is talking about using Stainless as the cutting edge and having a steel outer shell?
 
Jon, you could well be right. I read " shiny edge & dark spine " and focused on "dark spine" thinking that would be high carbon for center. I think the "shiny edge" indicates he does mean SS for the core. I suspect English isn't the OP's 1st language. I fully respect folks who have English as the 2nd language.
 
can a san nai be forge were stainless is the mode metal for a shiny edge & dark spine ?
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If you're asking about stainless being the edge/core material, generally the answer is NO. The reason? To create a hardenable, usable, San-Mai blade with stainless at the core....the core would have to be an austinizing stainless....meaning a hardenable/heat treatable type. That would generally mean a stainless in the 400 series, such as 420, 440, etc. Or another hardenable stainless. The issue is that the vast majority of those will simply not forge weld, and those that do require very complicated and specific set ups/conditions to forge weld....things that most of use do not have in our shops.

The "easy" way to forge weld a hardneable stainless is to place it in a container ("can") with a small tube on each end, and run argon gas through it to purge oxygen while its in the forge. The tough part is finding the correct temp..... it requires experimenting, and wasting some material/billets to figure out.

So..... All that being said, the short answer is....No, most folks do not have the capabilities in their shops to forge weld austinizing stainless steel in their home shop forges.
 
Devin Thomas (http://www.devinthomas.com/) is the true expert on SS San Mai. He uses AEB-L as the core with 304SS as the cladding. High or low carbon steel can also be used as the cladding. I've not used high carbon SS for the core, only lower carbon 416 SS for the cladding. For forge welding SS it needs to be seal welded all the way around the billet.
 
KenH said:
For forge welding SS it needs to be seal welded all the way around the billet.
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Did not do that either. Tack welds only. Man, I was doomed from the start. I just treated like any other steel.
 
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Chris, I'll respond to your PM here so all can see the answer. Ed is completely correct when he says about using the hardenable 400 series SS or any hardenable SS:
EdCaffreyMS said:
If you're asking about stainless being the edge/core material, generally the answer is NO. The reason? To create a hardenable, usable, San-Mai blade with stainless at the core....the core would have to be an austinizing stainless....meaning a hardenable/heat treatable type. That would generally mean a stainless in the 400 series, such as 420, 440, etc. Or another hardenable stainless.
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First allow me to say I am NOT an expert at all on any type of forge welding. I've done a few billets of San Mai, both SS cladding and carbon clad, and a single low layer Damascus. I have done a LOT of reading and talking (writing) with other experts like Devin Thomas (Hoss) and his son Larrin on the subject. What I have learned confirms what Ed says above that any hardenable SS is fairly difficult to forge weld, or even forge to shape. The only time I tried AEB-L as a cladding was a test. While it did forge weld, it cracked big time. Devin says to make it well the temperature must be controlled very close.

It seems the SS that works best for cladding on San Mai is a non-hardenable such as 416 or 410. Even the 303/304 SS should work. I'm told 410 SS is better than 416 because of the lower sulfur content of 410 SS. I've had good success using 416 SS as cladding because that's what I've got. The procedure sand clean all surfaces and seal weld all the way around the billet with it clamped tight to remove any air space inside the billet. Temperature needs to be around 2200°F to 2300°F for good welding.
 
Did not do that either. Tack welds only. Man, I was doomed from the start. I just treated like any other steel.
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That's usually the "first failure"..... I made the same mistake, along with most folks I know who've tried to make San-Mai. :)

Using the outside "layers" as a "can" was my answer. I personally like 416, along with a carbon or damascus core for San-Mai. I MIG all the way around the outside/cladding layers, creating a "can". In my experience..... if you can keep the oxidizing away, there's not much you can't forge weld..... of course there are a lot of other factors to get right too.
 
I'd not thought of it as creating a "can", but you're absolutely right. Seal welding all the way around does actually create the can with the SS being the outside of the can, with the high carbon being the "inside" of the can.
 
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