Bainite

A microstructural product formed in steels when cooled from the austenite state at rates or transformation temperatures intermediate between those which form pearlite and martensite, i.e., between about 800 and 500 K. It is an acicular structure of supersaturated ferrite containing particles of carbide, the dispersions of the latter depending on the formation temperature. Its hardness is intermediate between that of pearlite and martensite and exhibits mechanical properties similar to those of tempered martensite in a steel of the same carbon content.