Huntsman Process

The Huntsman process, also called the crucible steel process, produces highly uniform, high-quality steel by melting blister steel, along with scrap iron, inside small clay crucibles sealed and heated in a coke-fired furnace until the metal fully liquefies, letting impurities rise as slag and the alloy's composition become thoroughly even throughout the ingot. The English clockmaker Benjamin Huntsman developed the process in Sheffield in the 1740s, reportedly out of dissatisfaction with the inconsistent steel available for his own clock springs, and Sheffield cutlers and toolmakers came to prize the resulting steel for its purity and hardness even though many initially resisted adopting it. The process made Sheffield the world's leading center of fine steel production for over a century, and remained in use for specialty tool and cutlery steel into the twentieth century, well after cheaper bulk methods such as the Bessemer process had taken over ordinary structural steel production.