Heat treatment method after dissimilar welding PWSCC reduction in order to improve the material microstructure

摘要

The present invention relates to a first order water stress corrosion cracking reduction post heat treating method for improving microstructure of materials, comprising: a step of heating an outer surface of a dissimilar weld of a pipe to the temperature of 570-620 °C; a step of maintaining the temperature in a heated state at 4-10 hours; and a step of maintaining the outer surface of the dissimilar welded portion at the temperature of 570-620 °C while cooling (room temperature) the inner surface of the welded portion using cooling water or a sprinkling apparatus. The present invention relates to a heat treatment method after PWSCC abatement of the dissimilar weld to improve the microstructure of the materials which do not generate susceptibility to formation of stainless steel and which has precipitate which increases PWSCC resistance in the microstructure of the dissimilar weld.