Steel question

T

thegeek574

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Sep 3, 2010
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Before you ask, this is not a WHAT IS THE BEST STEEL AVAILABLE THAT CAN SHOP THROUGH CINDER BLOCKS AND STILL SHAVE HAIR. PRICE MUST BE UNDER 1 DOLLAR PER MILE. It is slightly more specific.

What is your favorite steel for a san mai core? I have seen everything from 1084 to W2 mentioned, but it was almost always simple carbon steels, or certain tool steels. How about A2, O1, 3V, 52100, 15N20, S7, ect. Any preferences?

Also, as an aside, does anyone know how hard it is to forge weld 3V?

Thanks,
Steven
 
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Steven

For your Wakazashi?? You serious about the cinder block? I hope not. Either of the steel you mentioned would work great. Have never worked with 3v so I cannot help there. So would 52100 and even possibly L6.
 
Steven

For your Wakazashi?? You serious about the cinder block? I hope not. Either of the steel you mentioned would work great. Have never worked with 3v so I cannot help there. So would 52100 and even possibly L6.
 
It was an exaggeration, and I hope I made the OP a bit clearer. I guess I was more wondering what steels are both practical to work with and benefit from the way that San Mai is constructed.
 
The steel will depend on the blade type and function.
For a yanagi-ba, W2 or Hitachi Blue/white will make a superior core.
For a wakizashi, 1084 would be better.
For a camp knife, O-1 or 1084 would be good.

52100 also works great. I haven't used it, but 15N20 seems a good choice, too.

I tend to think that going overboard on the core S-7, 3V, etc., isn't really necessary in san-mai.
 
Ok. Back home now and can type on the computer.

3V is in the catagory of D2, Air hardening tool steel. At least the CPM3v I can find. 7% chromium and lots of other stuff. A2 is also air hardening. Any of the Air hardening steel should be avoided in most forge welding applications.

Look at the purpose of San Mai.

It was to take a relatively small amount of high quality steel, Weld it down the center of the billet with iron outer layers to provide flexibility and mass. Since the center core was the part that did the majority of the cutting the simple carbon steel could be put to good use in a slightly higher hardness than otherwise used. The blade would not shatter like if it were of mono steel construction and through hardened. So any of the simple carbon steel would work well for san mai and it also is easier to forge weld.

We have talked about heat treating before. If you take a piece of good steel and heat treat it perfectly you will have a superior piece in the end. If you were looking at going a more traditional look with the possibility of a Hamon I would recommend W-2 or 1095. Keeping with the higher carbon content since there is going to be some carbon migration and we don't want to lose it all in the weld. If you did not care about the Hamon then go to the 52100. It still has the higher carbon and it is a tough steel, again heat treated properly.

Though 15n20, 1070, 1084, L6 can all be used, the lower carbon content might lend to problems. We could use a pure nickle barrier to prevent carbon migration. That we will explore when you come down to make the wak.
 
Wouldn't a waki require a pretty stress resistant core? The cladding would give some tensile strength, but still a sword is going to be whacking into stuff with way more force than a sushi knife.
 
What are the traditional Wakasashi and Katana made from?? Extremely Simple Carbon Steel. Iron and carbon with zero additives (other than innocuous trace elements). They held up great and still do. So I personally do not see a need to over-think the type of steel used. I make a heavy chopper from W2. This is a relatively simple carbon steel with just a touch of Vanadium added. I hack through tree trunks and so forth all the time and have yet to have one break or even chip out. Now if you abuse the blade and try to dig your firepit or outhouse hole and are hacking through rocks and such all bets are off. No steel is going to hold up to that in the form of a knife or sword blade. When the steel is jacketed in pure iron and heat treated properly for the task at hand even simple carbon steel will perform far beyond reasonable expectations.
 
The great advantage of making up a billet with whatever you want for the sides, a .040" pure nickel layer on each side, and a high carbon core, is that when the blade is forged out, the nickel makes a really nice faux-hamon. I have a diasho suminagashi-san-mai ( katana and wakizashi with damascus sides with carbon core) done this way ( with a 15 layer 52100 core) and people think it is an actual hamon.

I have taken two strips of cheap Thunderforged Damascus, two strips of nickel, and a core of 1095 and made a wonderful looking and cutting wakizashi for less than $100 in all materials.

Tip:
Chuck knows his stuff, but for those doing san-mai for the first times, watch the core as you forge the billet out. It can drift and get at an angle from spine to edge. Keep it centered or you will have very uneven sides when you etch.
 
Thanks all for the help. I think I will end up with W2, just because I have heard so much about it and I am curious to try it for myself. However, this has also been a very interesting read. I will try to do a WIP, and, if that does not work, then I will at least put up completed pictures of the final project.
 
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