车门用异种镀锌钢板激光焊接工艺及性能研究

Study on Process Characteristics and Mechanical Properties of Laser Welded Dissimilar Galvanized Steel Sheets for Car Doors

针对车门用0.7 mm厚的St17E和FC180/340HD异种镀锌钢板,开展激光焊接试验研究。研究关键工艺参数(激光功率、焊接速度)对焊缝表面形貌和横截面的影响,分析焊接接头微观组织分布特征,评估接头力学性能。研究结果表明,激光功率和焊接速度分别为1300 W和2.0 m/min时,焊接飞溅较少,焊缝表面光滑。随着激光功率增加和焊接速度减小,焊缝熔深和面积增加。焊接接头的St17E母材区的硬度最低,焊缝区硬度远高于母材区。优化参数条件下获得的焊接接头拉伸试样在St17E母材区发生断裂。

The dissimilar galvanized steel sheets with thickness of 0.7 mm St17E and FC180/340HD for car door were tested and studied for laser welding process.The effects of key process parameters(laser power and welding speed)on the weld surface morphology and weld cross section were investigated.The microstructure and mechanical properties of welded joints were analyzed and evaluated.The results indicate that when the laser power and welding speed are 1300 W and 2.0 m/min respectively,there are less welding spatters and the weld surface is smooth.As the laser power increases and the welding speed decreases,the weld penetration depth and weld area increase.For the dissimilar galvanized steel sheets welded joint,the hardness of the St17E base metal is the lowest,and the hardness of the weld zone is much higher than that of the base metal zone.The tensile specimen of the welded joint obtained with optimized parameters fractures in the St17E base metal.