High toughness high-speed steel member and manufacturing method thereof.

摘要

Disclosed are a high-speed steel member and a manufacturing method thereof. The member has a Nb content of 0 (incl.) to <2.0 % in the hard state after hardening and tempering and in its micro-structure, contains either or both of M6C and M2C type carbides representing a ratio of 0 to 2 % to the total area, and the remainder substantially consisting of MC type carbide. The difference of crystallization temperatures is 30 DEG C or more between MC type carbide and M6C or M2C type eutectic carbide. The high-speed steel member exhibits a high toughness and a small anisotropy of the mechanical properties, namely, a hardness of HRC 60 or more and a Charpy impact value ratio between the longitudinal direction and the direction perpendicular thereto in a forged material is 0.7 or more, and is quite useful for plastic working.