DIFFUSION JOINING METHOD OF DIFFERENT METAL

摘要

PURPOSE:To prevent creep embrittlement crack and to intensify a joint part by inserting a specific insert material between an iron or steel material of a ferrite system and a high-Cr-Ni alloy steel and joining these materials under specific conditions. CONSTITUTION:The insert material 6 is inserted between a joining material 4 of 1.1/4Cr-1/2Mo steel (ferritic iron or steel material) and a joining material 5 of 'INCOLOY 800(R)' (high-Cr-Ni alloy steel) in a vacuum chamber 1. The insert material 6 consists of amorphous metallic foil of an Fe-base alloy or Ni-base alloy. Diffusion joining is executed under conditions of 1373 to 1623K joining temp. and >=600 second joining time. The joining materials 4, 5 are reheated to >=1173K after cooling and are subjected to a post heat treatment after holding for >=300 seconds. A diffused layer is formed in the joint part, by which the thickening of carbon at the joint boundary and the precipitation of carbon are obviated. The creep embrittlement crack is prevented and the joining is surely executed.