METHOD OF COMBINED HEAT TREATMENT OF QUENCH-HARDENED STEEL MEMBER, AND QUENCH-HARDENED STEEL MEMBER

摘要

PPROBLEM TO BE SOLVED: To provide a method for manufacturing a quench-hardened steel member having a high peeling strength of a nitrogen compound layer to a steel base even when the high surface pressure exceeding 2 GPa is applied to the nitrogen compound layer formed on a surface of a steel base, and capable of taking sufficient advantage of the nitrogen compound layer having the characteristic of excellent slidability, high wear resistance, and high seizure resistance, and the quench-hardened steel member. PSOLUTION: In a method of combined heat treatment of a quench-hardened steel member with the nitriding and the induction hardening being combined with each other, and the quench-hardened steel member, a nitrogen compound layer 2 is formed on a surface of a steel base 1 through the nitriding, and nitrogen is diffused into a surface layer part 1a of the steel base 1 covered by the nitrogen compound layer 2. The nitrogen compound layer 2 of the thickness of 1 m which is unoxidized after the induction quenching with its quenching atmosphere being the ammonium gas atmosphere, the vacuum, the low-oxygen atmosphere or the like, is made to remain. The surface layer part 1a of the steel base 1 is provided with an effectively hardened layer depth of 200 m being the hardened layer including a fine martensitic structure containing nitrogen. PCOPYRIGHT: (C)2011,JPO&INPIT