Making San Mai in a different way

N

Natlek

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Jun 9, 2015
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Ok guys , what if I use welder and simple weld stainless steel on carbon steel blade. In this way , I have complete control how it will look finished knife blade ? I try to weld with stainless welding electrode on 15N20 and it works .................I'm most interested what will happened with carbon in carbon steel ??

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Something like this.......

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Any knife made in this manner will require a really solid anneal and normalization. You are also likely to get microfracturing through your welds. Carbon will migrate in your puddle, so you will just get a hazy transition between the blade and weld filler.

If you want to do this, preheat your blade (probably to 700+F) prior to welding. This will prevent martensite transformation in your puddle as it cools. Form a structural standpoint, I can't imagine that this would do anything very positive for a blade. From a visual standpoint, you may get some cool patterning in your cladding from inconsistent carbon migration through your puddle, after you etch.

My recommendation is to cut a cupon of 1095 and try it. If you have access to a TIG welder, you will be able to control your patterning more easily, and could pick your filler rather than being limited to your traditional weld fillers. It is also gonna warp the crap out of your parent stock, so you are going to have to be very careful to get it back to straight and keep the high carbon where you want it in the edge.
 
Thanks @ joedhiggins :thumbsup: Preheating blade is good idea .Yes I have TIG also but I think that with electrode I will do job faster ..... one more question ...carbon in part where I will not weld will be all there , right ?
 
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Yup. Only the puddle, and to a much smaller extent the heat affected zone will have any carbon migration. And even then, the carbon wont go away. You will have very little decarb in this process. Just migration.

Lets say you took a piece of 1/8" 1095 and ran 7018 electrodes. I would guess that the very core of the steel between weld pads would be still pretty close to 1% carbon. As you got to the very exterior of the puddle, you would be down in the .02% carbon range. THis is a guess, but especially with stick where the puddle is heavily agitated, I imagine you will have a lot of carbon migration. In the drawing you provided, the edge of the knife would still be 1095.
 
That is pretty slick. I can't recall anyone else doing that process. I think it is a lot of work for larger kitchen knives but I would be interested how it works out for hunting/utility knives. You are essentially painting on a permanent jacket.
 
It will work this way , what do you think Rick ?
No kitchen knives ...for now :) Small ,say 4-5 inch long blade would be perfect for this ...And I think that its time for me to make my first Bowie knive...with welded san mai .
Like you say it is essentially painting on a permanent jacket like Picasso with brush:D
 
I really don't know if it will work.... that is your job now, brother. I say, go for it!
 
I agree and look forward to seeing how it turns out. I can see this as a way to make a lot of different patterns, put a signature or other pictures in the blade.
 
Kevin McGovern said:
I think keeping the welds clean would be critical.
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If he is stick welding, clean is a relative term. Not rusty is clean even for 7018. It will blow right through mill scale. That being said, I would probably pickle it before welding. If I was gonna TIG it, I would probably etch and wire wheel or grind.
 
weo said:
I agree and look forward to seeing how it turns out. I can see this as a way to make a lot of different patterns, put a signature or other pictures in the blade.
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I think that best is to start with to some degree already grind blade ? Something like this .....? Red is stainless of course ?
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I would do it on flat bar I think. That way you dont have too much carbon migration from the center of the blade. Could try it both ways and shee how they look when etched.
 
312 or 309 should work, I am assuming you are planning on a carbon steel core, not SS? I had been thinking a mild steel jacket. I have not tried to heat treat HCS welded up with 312 or 309, so there is some potential for it to act weird there. You may get some chromium migration, which will increase hardenability of the puddle. I don't think that this will be a huge deal, but it might potentially complicate things.
 
Yes , for first try I will use carbon steel for core .I have 1095 , 52100 ,80crv2,15n20 .....and many other .I think that first will try with 1095 ....?
 
I'm interested to see how it looks before and after HT once it is ground/milled flat.
 
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