junker Posted July 3, 2009 Share Posted July 3, 2009 ok, since the point of welding a billet is to get the flexibleness of lower carbon steels in the middle of a blade and higher carbon hardness on the outside, would it work to have the center of the billet mild or like a spring steel and the outside a very hard tool steel? just would like to know. Quote Link to comment Share on other sites More sharing options...
Frosty Posted July 3, 2009 Share Posted July 3, 2009 It's called "San Mai" (three layers) in Japan. Frosty Quote Link to comment Share on other sites More sharing options...
junker Posted July 3, 2009 Author Share Posted July 3, 2009 i just can't help but think... since it;s kinda like a sandwich... wouldn't the mild steel end up being the edges? i could see how it would work if you folded the crabon steel over the mild.... but i was talking like one piece in the middle and 2 carbon on the outside. i just think the mild would end up being your edges if you were trying to make a double edged sword. Quote Link to comment Share on other sites More sharing options...
Frosty Posted July 3, 2009 Share Posted July 3, 2009 Picture this. A wedge shaped middle layer of milder steel or iron with two wider pieces of HC sandwiching it meeting at the edge and a small piece of HC closing the spine. When welded together the edge is HC steel for a good distance in. Fosty Quote Link to comment Share on other sites More sharing options...
Pault17 Posted July 3, 2009 Share Posted July 3, 2009 Yet another mystery un-veiled. Again, thanks to all. Sam I really love your bold signature. never been much of a collector of anything myself. Quote Link to comment Share on other sites More sharing options...
markb Posted July 4, 2009 Share Posted July 4, 2009 Sam Great explanation.:D Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted July 4, 2009 Share Posted July 4, 2009 (edited) ok, since the point of welding a billet is to get the flexibleness of lower carbon steels in the middle of a blade and higher carbon hardness on the outside, would it work to have the center of the billet mild or like a spring steel and the outside a very hard tool steel? just would like to know. Read up on Carbon Migration. There is not much of any truth in the higher lower carbon statement just made. More false Myths made from assumptions rather than lab testing. Carbon migrates very fast at welding temp's, while a San-Mai construction may actually have a portion of the carbon differences remaining, its not much if at all, the old link is dead, but there is a paper on the web showing even one forge weld, with no folding made, the test of a203e and 1095 had homogeneous carbon levels. Edited July 4, 2009 by steve sells Quote Link to comment Share on other sites More sharing options...
Dave Budd Posted July 4, 2009 Share Posted July 4, 2009 although carbon will migrate at a rate of (approx) 0.4mm per hour at temperatures between the two upper phase changes. So you have to keep the metall working hot for a long time to make any difference on a 6mm thick blade made from three layers If it didn't help to reenforce the blade I'm sure the scandinavians and the japs wouldn't still use it for hard edges cutting tools/knives Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted July 4, 2009 Share Posted July 4, 2009 I used to think the same thing, but as the testing has proved, most people dont keep it low enough, and as the temperatures rise so does the speed of migration Quote Link to comment Share on other sites More sharing options...
Dave Budd Posted July 4, 2009 Share Posted July 4, 2009 steve, I'm always happy to be corrected when I'm wrong or reading from old text books. Do you have a link to the research by any chance? Apprenticeman, I have no doubt at all that most of what both nations do is down mostly to tradtion Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted July 5, 2009 Share Posted July 5, 2009 (edited) I will try to find a new source for the testing, as when I pulled up the old thread the link was not functional anymore. Edited July 5, 2009 by steve sells Quote Link to comment Share on other sites More sharing options...
junker Posted July 5, 2009 Author Share Posted July 5, 2009 Thanks guys... got any more advice up ur sleeves? I'm working on making a straight razor outta some cable that I welded into a billet... just heated the cable to welding temp and twisted and then heated it again and flattened... cut it into 3 segments, stacked them, and welded them again... any advice y'all can think of 4 the completion of this project will be apreciated.... it's gonna be a gift 4 my neighbor for letting me use the steel he had laying around. Quote Link to comment Share on other sites More sharing options...
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