高强钢熔化极活性气体保护电弧焊免预热焊接技术综述OA

As the demand for sustainable manufacturing practices increases,preheat-free welding emerges as a promising so-lution to reduce energy consumption in welding processes.However,the primary challenge lies in preventing welding cracks,which can result from several factors:mismatched thermal expansion coefficients of base materials,excessive re-sidual stresses,brittleness in the welding zone—such as hard brittle structures,Widmanstätten structures,and hydrogen em-brittlement.The lack of preheating leads to a smaller temperature differential before welding,slower cooling rates,and di-minished moisture on the surface of welded components.To effectively mitigate cracking,enhancing the resistance of both the welding materials and the overall process is essential,compensating for the typically beneficial effects of preheating.This necessitates a comprehensive approach that considers the base material,welding wire compatibility,and the optimiza-tion of welding techniques.Moreover,employing finite element modeling to predict deformation and residual stresses can significantly improve preheat-free welding methods.This paper focuses on elaborating the key technical pathways for preheating-free MAG welding,including the selection of base materials with low hardenability,the development of adapt-able welding wires,the strength matching between welding wires and welding processes,and process optimization measures such as the control of welding heat input and interpass temperature.It provides a reference for the engineering application of preheating-free MAG welding technology for high-strength steels.