Hello all our December topic is san mai steel. The Japanese originally used this construction method in their swords, nowadays it has been taken to new heights. So lets see some blades that you have made. ALso talk about the materials used and the process of making your san mai steel. Also if you have any questions about the technique. I do not make much of it but I know some of our members do. I look forward to seeing what you have and learning more about this process.
Brion
Brion Tomberlin
Anvil Top Custom Knives
ABS Mastersmith
Since the beginning of my San-mai activity, I have used 1095 and 410/420 stainless. I avoid 416 because of the sulfur content. Sulfur is added for better machinability - meaning, in a nutshell - sulfur helps it to come apart. That is the last thing I want my stainless to do is come apart, since it really doesn't much like being forged in the first place. I have had 416 split right down the middle when moving too far in one heat.
I also happen to have a rather nice supply of some old stock 1095 from Aldo that has a nice supply of vanadium and manganese. It's the manganese that etches so black - which I like. And it's 3/8" thick and 1 5/8" wide. On this I add 1/4" stainless.
I've been making this regularly for about 7-8 years. Over this time I see so many guys try to weld their three parts that are already near their final dimension when they start. This means the parts have been at heat and under pressure very little time. And not surprisingly, those same guys often complain about delamination. You can also see they spend very little time at welding heat by the obvious lack of activity in the migration zones.
After I get my billet welded and drawn out to nearly it's final thickness, I turn my bar on edge and forge down the ricasso and draw out the tang. If there was any chance of delamination it would happen at this time. I swear - in all the time making this, I have never had a delamination.
You need to have your process and tooling pretty well dialed in and an ability to control your heat.
Expect failure. It's how we learn.
In this image from Kevin Cashen you can see the core steel at the far left. As we move to the right we can see where the carbon has vacated the carbon rich core steel and migrated to the carbon deficient stainless to the right in an effort to equalize. It is that second zone that etches silvery in my photos. It's basically raw iron now with the absence of carbon. Then we see the carbon deficient zone to the far right. (I'm so glad you made this available, Kevin.)
Karl B. Andersen
Journeyman Smith
Kevin as always thank you for sharing, and such a beautiful knife!
I like making San Mai with Wrought iron and Aldo's 1084. It welds pretty easily.
