Microstructural changes during short-cycle heat treatments of cold-work tool steels

Short heat treatment cycles like for induction hardening are rarely investigated on alloyed cold-work tool steels. Therefore little is still known on the microstructural changes during austenitising, quenching and tempering under these conditions. As these investigations show there are significant changes in the alloy distribution depending on the austenitising parameters. Subsequent quenching can lead to high contents of retained austenite. During short cycle tempering the transformation of the tetragonal martensite and the decomposition of the retained austenite is shifted to significantly higher temperatures. When applying appropriate austenitising and tempering parameters similar hardness and toughness properties can be achieved as for standard heat treatment condition leading to good hardness values with a fine ductile fracture surface.