Thread: Iwasaki Tamahagane Information

Originally Posted by Bruno

More likely that this is a common process. Iwasaki was unlikely to be the first to think of this because it just makes sense. Folding is a very inefficient way to get rid of bloomery slag and inclusion. Plus, tamahagane starts out witha very high carbon content (the stuff for edge sections in any case) but after all the folding and forge welding, the carbon drops substantially if done by traditional methods. Mike Blue once told me that about 60% of tamahagane is lost as forging scale this way, and the carbon content drops from 1.4 to 0.7 to make sword grade steel.

Bruno,

Those are very good general numbers. I typically lose 50% over 13 folds. The highest Carbon content I have ever had is about 1% in the finished steel. Usually, I end up with about 8% Carbon. Plus, the Silica never completely goes away. The more I look at the micrographs, the more I think the Iwasaki steel was melted, at some point.