Cast iron
Cast iron
Highly carbonized iron, the direct product of the blast furnace; -- used for making castings, and for conversion into wrought iron and steel. It can not be welded or forged, is brittle, and sometimes very hard. Besides carbon, it contains sulphur, phosphorus, silica, etc.
Cast-iron , adjective
Made of cast iron. Hence, Figuratively: like cast iron; hardy; unyielding.