plain carbon steels

Steels which contain 0.1% to 0.7% carbon, with no other, deliberately introduced alloying elements. The properties of these steels vary with the carbon content and they are divided into four divisions: low-carbon steels contain up to 0.15% C; mild-carbon steels; 15% to 0.29% C; medium-carbon steels 0.30% to 0.59% C; and high-carbon steels 0.60% to 1.70% C.