复合板基层厚度对激光焊接头腐蚀性能的影响

目的通过探索基层金属厚度对复合板激光穿透焊接的影响规律,分析其影响度与焊接速度、激光功率的差别,为双金属复合材料激光穿透焊接提供更多的技术支撑。方法以焊接速度、激光功率和基层金属厚度为变量,设计了三因素三水平的正交实验,对X65/DSS2205层状双金属复合材料进行激光穿透焊接实验,对不同焊接条件下接头的显微组织进行观察分析,采用EDS面扫方法对焊缝复层区进行成分扫描,测量接头复层侧动电位极化曲线,并比较了基层金属厚度的影响度较焊接速度与激光功率的大小。结果双金属复合板激光穿透焊接接头显微组织在厚度方向存在明显的分层;基层金属厚度为1.2 mm时,复层贵金属元素保留量最大;随着基层金属厚度的减小,接头综合耐腐蚀性能提高;基层金属厚度对接头耐腐蚀性能的影响小于焊接速度和激光功率2个变量;焊接速度为2.5 m/min,激光功率为3500 W,基层金属厚度为0.8 mm时,接头耐腐蚀性能最优。结论基层金属厚度对于复合板激光穿透焊接接头的焊缝复层元素含量、以及接头复层一侧耐腐蚀性能都有较为明显的影响,但相比于焊接速度与激光功率,其影响度相对较小,因此在进行复合板激光穿透焊接时,在选定基层金属厚度后,仍要对焊接速度和激光功率进行优化工艺设计。

Effect of Base Thickness of Composite Plate on Corrosion Performance of Laser Welding Joint

The paper aims to study the influence rule of base metal thickness on laser penetration welding of composite plates, analyze the difference of the influence degree between base metal thickness, welding speed and laser power, to provide more technical support for laser penetration welding of bimetal composite materials. With the welding speed, laser power and base metal thickness as variables, the orthogonal experiment with three factors and three levels was designed to conduct laser penetration welding of bimetallic composite X65/DSS2205. The microstructure of the joints under different welding conditions was observed and analyzed; the composition of the weld composite layer was scanned by EDS surface scanning method; the dynamic potential polarization curve of the joint composite side was measured; and the influence of base metal thickness, welding speed and laser power was compared. The results showed that the microstructure of the welded joint was hierarchical along thickness direction of the welded joint. When the thickness of base metal was 1.2 mm, the maximum amount of precious metal elements was retained. With the decrease of base metal thickness, the comprehensive corrosion resistance of joints was improved. The influence of base metal thickness on the corrosion resistance of the joint was less than that of welding speed and laser power by two variables. In this study, the joint had the best corrosion resistance when the welding speed was 2.5 m/min, the laser power was 3500 W, and the base metal thickness was 0.8 mm. The base metal thickness has a significant influence on the element content of weld composite layer and the corrosion resistance of the composite side of laser penetration joint. However, when compared with welding speed and laser power, its influence is relatively small. Therefore, in laser penetration welding of bimetal composite plate, the welding speed and laser power should be optimized after the thickness of base metal is selected.