Fabrication of Ultrafine Grained High Speed Steel with Satisfactory Carbide Dissolution by Electropulsing Treatment

Abstract

Microstructure of M2 high speed steel (HSS) after electropulsing treatment (EPT) was studied. The secondary carbides precipitated during pre-tempering were dissolved completely during EPT. But the secondary carbides in the starting microstructure cannot be dissolved completely upon conventional reheating to the temperature same as that during EPT. The austenite grain size was ultra-refined by EPT. This study provides a new way to refine austenite grain size in HSS without diminishing the dissolution amount of carbides.