Cementation

—The oldest method of steel manufacture. Bars of wrought iron, of best quality, are buried in powdered charcoal within fireclay boxes, the whole being sealed or cemented with fireclay. These cementation boxes are placed within a furnace and brought to a bright red heat, the length of the heat depending upon the amount of carbon desired in the product; the proce may continue for a fortnight with highly carbonized steels. From their being covered with blisters, the steel bars produced are known as blister steel; they are broken up, piled, heated in a reverberatory furnace, and subjected to rapid blows, which gives them a fibrous quality, forming shear steel; a repetition of the piling proce produces double shear steel, also called, crucible steel.