Any good source suggestions (and alloy) for stainless san-mai cladding?

[Chris Railey]

Going to do some stainless San-Mai shortly. Its just an itch I have to scratch. Which alloys do you think is best cladding for this and a good source if you do not mind sharing. Thanks in advance.

[Ed Caffrey]

Hi Chris!

Definitely 410 or 416 Stainless for the cladding. Either is going to give you the best chances for success. I have also done some San-Mai with 316, and 304. It CAN be done with 316, but you have to fight it the entire way. For me 304 was a failure from the start.

These days I don't think there is a "good" source.

What I usually do is go to ebay and try to find a largish chunk of either 410 or 416 for a decent price, then I forge it to the sizes I need. Last time I found a 1 1/2" wide X 3/4" thick X 5' long "drop" and got it for $100 with shipping included. Forged out, that makes a bunch of 1/8" thick or less cladding material.

[KenH]

https://www.admiralsteel.com/shop/ has both 410 and 416 SS in different thickness. I'm using the 410 SS for cladding and it works pretty good. With only .062" on each side it doesn't take much "drawing out" to get a decent thickness for a blade.

[Chris Railey]

Both good ideas, thanks guys. I think I also remember 410 and 416 will show carbon transfer better, kind of adding to the pattern so I will go that direction...thanks again.

[Chris Railey]

Just kind of found this...Not a bad price.

https://www.ebay.com/itm/25419771598...-desc-maincntr

[KenH]

Chris, when you talk about "carbon transfer", do you mean with the SS cladding almost showing the carbon steel thru the SS? That might be what I had that to happen on a blade. I used .040" 26C3 for the core with a .062" cladding on each side. Once it was all forged up, ground smooth, and thinned down to .090" or so the SS almost didn't show up at all. Almost as if it were carbon steel.

Is that what you mean by "carbon transfer"?

[Chris Railey]

Keep in mind this is academic knowledge at this point I have not made stainless San-Mai yet. But I have made a lot of regular San-Mai. Its like when you make San-Mai with mild steel and there is a darker line just above the actual demarcation line between HC and mild steel. It looks kind of like a hamon. My understanding is, that is carbon migrating from the HC steel to the Mild. It looks neat to me and gives the whole thing more appeal. The 410/416 stainless will show that migration better than a 300 series, or so I have read.

My only guess in your description above is maybe with that thin a cladding there was migration causing your thin cladding to etch darker? I know some stainless steels will resist etching more than others, staying brighter in the etch but I do not know enough about the alloys yet to give an opinion. That is really at the heart of why I want to move to stainless San-Mai because I cannot get the contrast I want with mild steel.

[KenH]

Yea, now I know what you're talking about with carbon migration, that line I see sometimes with San Mai - after all, 410/416 SS is very low carbon. The layer of SS cladding being too thin is what I was thinking, I'd not thought about carbon migration from the HC to the SS cladding, and with it thin it would allow some dark etching. My San Mai for hunting knifes works just fine since they're usually >1/8" thickness. It's kitchen knives where I have the problem since I like thin blades there, well less than 1/8", more like .070 to .090" thick and that doesn't leave much room for cladding with a .040" core.

Putting a layer of copper between the cladding and core works good, but with .020" copper on both sides, then .040" core, that's .080" right there before it's "squished" down with press.

Later

[Ed Caffrey]

Concerning/associated with the carbon migration.... here's something to think about, that I have come to realize over the years of doing it, is true.....

The best looking SS San-Mai, is a San-Mai with the poorest welding/forging technique. The opposite is also true.... the better the wedling/forging technique, the poorer the look. Sound crazy? Here's the explaination.... the best looking SS San-Mai has the biggest/boldest carbon migration "stripe" where the SS and the core/carbon steel meet. In order to achieve this, the billet must be soaked too long, at too high a temp, and there is significant carbon migration into the SS, which creates that bold stripe that everyone likes/have come to expect with a SS San-Mai. When good/proper welding/forging technique is used, the carbon migration is far less, and consequently, that "stripe" of carbon migration is far less (as in far more narrow).
The good news is... if you know this, and take it into consideration when building the billet, you still can come out with a great cutting, high quality blade. That is accomplished by leaving the core a bit thicker..... that way you make it past the depth of carbon migration when grinding/in the finished blade.

[KenH]

That all makes good senses Ed - Can also explain why the SS cladding on a blade looked like it was "printing thru" to the carbon steel core. Too much heat while welding allowing carbon migration to from core to cladding. On that blade I do remember pushing the heat a bit more than normal to be sure of sufficient heat to weld core (26C3) to the 410 SS cladding.

Something I've done in the past to get that bright line between cladding and core is to use a .005" layer of pure nickel. Welds good and sure makes a nice bright line.

[Chris Railey]

No wonder I hardly ever get a migration line on my mild steel San-Mai...