Effect of molybdenum on continuous cooling transformations in two medium carbon forging steels

Continuous cooling transformations in two medium carbon microalloyed forgin g steels have been studied. The influence of austenite grain size and molyb denum content on diffusion-controlled transformations and displacive transf ormations has been thoroughly analyzed. Moreover, a study of the austenite grain structure previous to the transformation has been carried out. In thi s sense, the evolution of austenite grain size with austenitization tempera ture has been experimentally analyzed. That allowed to detect the temperatu re at which an undesirable microstructure with a duplex grain morphology st arts to form. Finally, continuous cooling conditions to reach a final micro structure formed mainly of acicular ferrite in industrial forging processes has been determined. (C) 2001 Kluwer Academic Publishers.