ABSTRACT
One of the most important technological processes is the hardening of steel by quenching. If the steel is quenched rapidly enough from the austenitic eld, there is insufcient time for eutectoidal diffusion-controlled decomposition processes to occur, and the steel transforms to martensite-or in some cases martensite with a few per cent of retained austenite. This transformation is important and best known in connection with certain types of stainless steels, quenched and tempered steels and ball bearing steels. Important recent developments involving the martensitic transformation in steels include maraging steels (precipitation-hardened martensite), TRIP steels (transformation induced by plastic deformation), ausforming steels (plastically deformed austenite prior to quenching) and dual phase steels (a mixture of ferrite + martensite obtained by quenching from the γ + α eld).
