The microstructure and properties of some low-carbon 4% manganese steels containing niobium and vanadium

Abstract

Low-carbon 4% manganese steels containing niobium and vanadium additions have been controlled-rolled to either 950 or 800°C followed by air cooling or water quenching to room temperature. Decreasing the finishing-rolling temperature had no significant effect on strength but lowered the 55 J impact transition temperature in the case of the air-cooled specimens. Previous Swedish work has emphasized the importance of keeping the carbon below 0.04%, but the present study shows that alloys containing 0.07–0.09%C can produce similar ductile-brittle transition temperatures. The replacement of niobium by combined additions of niobium plus vanadium or vanadium alone had no significant effect on the properties. A microstructural study attempted to explain the variation in mechanical and impact properties.