Military Dao, casted steel?

[Timo Nieminen]

I guess that Roland refers to traditional Chinese steel made by decarburising cast iron. Old process, became widely used during the Han dynasty, and was used into the 20th century.

Efficient, since the smelting furnace can be run continuously (since the output is molten cast iron and molten slag) - feed in charcoal and ore from the top, tap the output from the bottom. Efficient because you don't waste energy heating the furnace (except right at the start); these furnaces could operate continuously for 40 days or so (not great compared to modern blast furnaces which can operate continuously for 40 weeks).

Things which can usefully be made from cast iron are cast on the spot (tools, woks, etc.), and for things which need to be tougher, you decarburise the cast iron until you get steel of appropriate carbon content. The old Chinese name for such steel was "fried iron", since pieces were heated and stirred in the decarburisation process.

I have at least on kukri marked "cast steel" - it's forged rather than cast. The "cast steel" refers to the steel used - modern (18th to 20th century) Western crucible steel, where blister steel is melted in closed crucibles, allowing slag to be removed. The molten clean steel is then cast, and used for subsequent forging.

Originally Posted by mariusgmioc

I don't think there is such a thing as cast steel. Due to its high carbon content, steel cannot be properly cast. If it can be cast, then it means it has a lower carbon content an we are talking about iron... cast iron more precisely.

These days, there are plenty of steel castings. Note that cast iron has more carbon than steel (usually 3-4%). It's easier to cast than steel or iron since the carbon lowers the melting point.