301L不锈钢激光填丝焊接头腐蚀性能研究

Study on the corrosion performance of 301L stainless steel laser filler wire welding joint

不锈钢的车体部件的腐蚀主要是晶间腐蚀,结合不锈钢自身的组成成分以及焊接过程中的相关工艺参数,研究线能量在窄间隙激光填丝焊中对焊接接头腐蚀性能的影响,设计了不锈钢焊接接头的腐蚀试验方案,并从贫铬理论出发阐述其对于焊接接头腐蚀行为的影响机理。以6 mm厚301L不锈钢板材作为基体材料,以ER308L焊丝为填充材料,研究线能量分别为120 J/mm、150 J/mm、180 J/mm时窄间隙激光填丝焊焊接接头的腐蚀行为。对三组不同线能量下窄间隙激光填丝焊焊接接头进行电化学测试,并在浸泡腐蚀之后进行电镜扫描,表征对比腐蚀形貌,得出线能量为150 J/mm时接头的腐蚀性能最佳。

The corrosion of stainless steel car body parts is mainly intergranular corrosion,and the theory of chromium deficiency plays an important role in explaining the corrosion behavior of stainless steel. Combining with the composition of stainless steel and the relevant parameters in welding process,the influence of heat input on the corrosion performance of the welded joint in the narrow gap laser filler wire welding is studied. A corrosion test scheme for welded joint of stainless steel is designed,and based on the theory of chromium deficiency,its influence mechanism on the corrosion behavior of welded joints is discussed. In this paper,the 6 mm thick 301 L stainless steel plate is used as the base material and ER308L welding wire is used as the filler material. The corrosion behavior of the welded joints in narrow gap laser filler wire welding is studied when the heat input is 120 J/mm,150 J/mm and 180 J/mm,respectively. Electrochemical tests are carried out on the welded joints of narrow gap laser filler wire welding under three groups of different heat inputs. After immersion corrosion,three groups of samples are scanned by electron microscope,and the corrosion morphology is characterized and compared to conclude that the corrosion performance of the joint is best when the heat input is 150 J/mm.