激光功率对2195铝锂合金光纤-半导体激光复合焊接形貌与气孔的影响

光纤-半导体激光复合焊接技术充分结合了光纤与半导体激光热源的优势,在激光加工领域拥有巨大的潜力.针对2195铝锂合金开展光纤-半导体激光复合焊接试验,并定量研究激光功率对焊接形貌与气孔的影响.结果表明,光纤激光功率显著影响焊缝熔深,半导体激光功率显著影响焊缝上熔宽.基于回归分析方法建立焊缝横截面积预测模型.此外,光纤与半导体激光均对焊缝气孔缺陷的控制起着重要的作用,较高的光纤激光功率有利于降低气孔缺陷.对于4 mm厚2195铝锂合金,采用光纤激光功率为3.0 k W、半导体激光功率为2.5～3.0 k W时,熔池温度高且光纤-半导体激光复合作用范围大,焊接接头气孔缺陷少.     

Thermal cycle and its influence on the microstructure of laser welded butt joint of 8 mm thick Ti-6Al-4V alloy

Ti-6Al-4V alloy is extensively used in the manufacture of components in aviation. In the current study, the laser welding process is adopted to joint the Ti-6Al-4V alloy plate which has the thick of 8 mm. A three-dimensional finite element model is established to simulate the temperature distribution of laser welding process. The thermal cycle curves are produced on the strength of the simulation results. Meanwhile, the microstructure characteristics of the welded joint are investigated combined with simulation results. The results show that weld zone, heat affected zone and based metal experience similar thermal cycles process and the cooling rate has an important influence on the formation of microstructure. Moreover, the simulation results are well matched with experiment results.     

Invar钢多层摆动焊接过程的数值模拟

以19. 05 mm厚Invar钢板作为研究对象,通过研究Invar钢的多层摆动焊接,得到多层摆动MIG焊焊缝。利用建模软件建立和实际焊缝一致的有限元模型并进行分析计算,得出焊接过程中温度场的变化过程,对瞬时温度场和焊接热循环曲线进行分析,得出焊接过程中试样整体温度场的变化过程。结果表明,焊接时间越长,焊接速度越慢,熔池尺寸越大;热循环曲线的斜率代表该点温度变化的速率,斜率越大,温度变化速率越快,相对的,热循环曲线随着热源靠近发生剧烈地变化,远离热源变化平缓;直线焊接的热循环曲线为一条平滑的曲线,摆动焊接的热循环曲线为一系列均匀摆动的折线,折线摆动的频率与焊枪摆动的频率一致。