镁合金激光-氩弧复合焊再制造熔覆成形工艺优化

目的针对镁合金零部件表面损伤和体积损伤的修复问题,采用激光-氩弧复合焊修复技术,通过对工艺参数的优化,制备出组织性能良好、缺陷少的熔覆层,形成相适应的优化修复方案,为镁合金高效修复提供技术支撑。方法采用激光-氩弧复合焊技术在ZM5合金上制备熔覆层,调整送丝速度、焊接电流、焊接速度、激光功率四种工艺参数,研究工艺参数对熔覆层成形性和尺寸的影响。结果送丝速度越小,熔覆层越光滑,呈现为扁平状,且熔宽、熔深较大。当焊接电流大于105A时,激光-氩弧复合焊的强度和焊接效果最好。焊接速度对熔覆层尺寸的影响很大,随焊接速度的增加,熔覆层向细、窄、小发展。当激光功率增加到400 W时,复合焊热输入提高,熔覆层铺展性增强。结论综合熔深、熔宽、余高的离差量,为得到成形性良好、尺寸较大的熔覆层,焊接速度应为5 mm/s,送丝速度应为23 mm/s,激光功率应在400~500 W之间,焊接电流应为120~140 A。

Process Optimization of Depositing Formation Remanufacturing of Laser-TIG Hybrid Welding on Magnesium Alloy

Objective To repair the surface and volume damages on parts of magnesium alloy, laser-TIG hybrid welding is used. Through optimizing process parameters, the depositing layer with good microstructure and properties and less defects are welded and the corresponding optimized repairing plan is formed, which provides support for surface and volume damages on magnesium alloys repairing. Methods Depositing layer on ZM5 magnesium alloy was welded by laser-TIG hybrid welding. By adjusting the wire feed rate, welding current, welding rate and laser power, the influence of process parameters on the formability and size of the depositing layer was explored. Results The smaller wire feed rate was, the smoother the depositing layer would be; and the penetration and width of the depositing layer were larger. When the welding current exceeded 105 A, the strength and welding effect of laser-TIG hybrid welding were the best. The welding rate had a great impact on the depositing layer size. With increase of weld feed rate, the depositing layer would become thinner, narrower and smaller. When the laser power was increased to 400 W, the heat input would be improved and the ability of depositing layer spread would be enhanced. Conclusion Taking the above all into consideration, in order to obtain the depositing layer with good formability and larger size, the welding rate and depositing layer feed rate should be taken at 5 mm/s and 23 mm/s, and laser power should be taken between 400 W to 500 W, and the welding current should arrive at between 120 A and 140 A.