BUILD-UP WELDING FOR PRESSURE VESSEL AND PRESSURE VESSEL

摘要

A nuclear reactor vessel (1) has low alloy steel as its base material (11), and on the inside surface of the base material (11) are layered a plurality of build-up layers (22-24), which are formed by multilayer build-up welding with Inconel 690 alloy welding material, which is a Ni-base alloy based welding material. The build-up layer (22), out of the plurality of build-up layers (22-24), that is the initial layer layered directly onto the inside surface of the base material (11) is formed such that the Cr concentration does not exceed 16 mass% by build-up welding in which the dilution ratio is increased. High corrosion resistance can be obtained, and in post-weld heat treatment after the multilayer build-up welding, formation of a hardened layer at the weld boundary due to carbon in the base material diffusing to the welding material side can be suppressed.