PROCESS FOR PRODUCING STAINLESS STEEL DIFFUSION-JOINED PRODUCT

摘要

A method for producing a stainless steel diffusion-bonded product is aimed for providing a stainless steel material diffusion-bonded product having excellent reliability of the bonded portion by using a "direct method" which can be performed with a work load equivalent to that of a conventional insert material insertion method, and the method includes directly contacting stainless steel materials with each other to unify the materials together by diffusion bonding, and in the method, at least one of the stainless steel materials to be contacted is dual-phase steel having an austenite transformation starting temperature Ac 1 point of 650 to 950°C during the temperature elevation and having an austenite + ferrite dual-phase temperature region in the range of 880°C or higher, and the diffusion bonding is advanced under conditions such that the contact surface pressure is in the range of 1.0 MPa or less and the heating temperature is in the range of from 880 to 1, 080°C while being accompanied by the movement of grain boundary caused when the ferrite phase in the dual-phase steel undergoes transformation to an austenite phase.