Process for achieving 2000 MPa H13 steel by eliminating temper embrittlement

A toughening-tempering process is devised to eliminate the second type of temper embrittlement, which is the strength-ductility trade-off during the tempering heat treatment process. The proposed methodology is implemented on H13 steel, with initial tempering at 500 degrees C for 1 h followed by subsequent tempering at 560 degrees C for 1 h. The result demonstrates an exceptionally high ultimate tensile strength of 2012.6 MPa, surpassing even that of the sample in a state of temper embrittlement. More importantly, the elongation and impact energy of the treated sample achieve as high as 8.2 % and 13.5 J, respectively, which is remarkably enhanced comparing with the embrittlement sample's figures of 1.4 % and 6.9 J. The microstructure analysis indicates that the tougheningtempering can retain the high-density dislocation in the temperature of temper embrittlement to improve the strength. On the other hand, recrystallization induced by high-angle grain boundaries improves the plastic deformation ability and obtain excellent ductility.