车用镀锌钢板光纤激光拼焊工艺研究

Research on Car Galvanized Tailor-Welded Blanks of Fiber Laser Welding

镀锌拼焊板的应用,不仅可以提升汽车的防腐性能,而且可以在保持同等强度的条件下,减轻车体重量。激光焊接与其他焊接工艺相比,有焊缝窄、强度高、热影响区小等优点。但是,拼焊间隙会造成焊缝表面凹陷,焊缝强度不够。通过光纤激光拼焊,在获得较好的侧吹保护气体参数后,以正交实验的方式研究激光功率与焊接速度对焊缝成形的影响。通过宏观金相实验、拉伸实验与杯突实验等检测手段,对焊缝的形貌、力学性能与冲压成形性能进行检测。确定激光功率为3 k W,焊接速度为4 m/min是最佳工艺参数。在最佳工艺参数基础上,研究拼焊间隙大小对焊缝成形的影响。结果表明,当间隙不超过0.15 mm(约为板厚的11.1%)时,可以获得良好的焊缝。

The application of galvanized steel tailor-welded blanks not only improves the corrosion resistance property of a car, but also reduces vehicle weight while the intensity maintains the same. Compared with other welding technologies, laser welding has lots of advantages, such as a narrow welding line, a high strength joint and a small heat-affected zone. However, the gap between the plates can cause surface depression and intensity deficiency. After obtaining suitable parameters of side-blown shielding gas, orthogonal experiment is designed to have a research on laser power and welding speed＇s influence on weld formation through tailored blank fiber laser welding. After that, metallurgical experiments, tensile tests and cupping tests are used to detect the performance, mechanical and deep stamping properties of the welding line. The result shows an optimum parameter when the laser power is 3 kW and the welding speed is 4 m/rain. On the basis of optimal parameters obtained, a further study is made on gap＇s influence on weld formation. The result shows that a nice welding line can be obtained when the gap is not more than 0.15 ram（about 11.1% of the plate thickness）.