Local heat treatment method for controlling residual stress with primary and auxiliary heating

Abstract

A primary heating band is applied to a weld to control a microstructure and hardness of the weld and uniformity of the structure to realize micro-control of the residual stress; an auxiliary heating band is applied a certain distance away from the weld to generate compressive stress on an inner surface of the weld to realize macro-control of the compressive stress. Reinforcement with a rib plate is eliminated, and a labor intensity and a construction period are reduced. The method reduces deformation near the weld and transfers the largest deformation to a non-weld zone; by applying the auxiliary heating and strictly controlling a time interval between primary heating and auxiliary heating, the structure is improved and the welding residual stress is controlled at the same time; a local heat treatment effect is optimized, and a small tensile stress or compressive stress is generated on the inner surface of the weld.