铝锂合金激光-等离子弧复合焊焊缝表面成形  

Weld surface formation in laser-plasma arc hybrid welding of an Al-Li alloy

作　　者：常保华[1] 李志宁[2] 周晶[1] 都东[1] 张骅[1] 

机构地区：[1]清华大学机械工程系,先进成形制造教育部重点实验室,北京100084 [2]军械工程学院火炮工程系,石家庄050003

出　　处：《清华大学学报（自然科学版）》2010年第8期1178-1182,共5页Journal of Tsinghua University(Science and Technology)

基　　金：国家自然科学基金资助项目(50705049);军械工程学院基金资助项目(200801005)

摘　　要：铝合金激光-等离子弧复合焊(LB-PAW)中焊缝表面成形质量差。为了解其形成机理和解决方法,建立了可考虑等离子弧力作用的激光-等离子弧复合焊熔池流动数值分析模型,研究了不同热源次序对熔池速度场的影响,并进行了不同热源次序条件下铝锂合金焊缝成形试验。结果表明:在单纯激光焊、复合焊等离子弧前置和等离子弧后置3种条件下,熔池表面流动环路及速度存在很大不同;复合焊等离子弧前置时焊缝表面出现较深凹坑,纹理粗大,成形不良,等离子弧后置时焊缝表面平整,成形良好。在铝合金1420的LB-PAW中,熔池流动与焊缝表面成形情况密切相关,等离弧力是影响焊缝表面质量的主要因素之一,建议采用"激光在前,等离子弧在后"的热源次序进行铝合金焊接。The weld formation is poor during laser beam-plasma arc welding （LB-PAW） of aluminum alloys. To study the causes and develop solutions, a numerical model was developed for the fluid flow in the weld pool in LB-PAW of 1420 Al-Li alloy. The effects of the plasma arc and its direction on the velocity field in the weld pool were then investigated numerically. In addition, the welds for various conditions were studied experimentally. The results show that the fluid flow pattern and the velocity at the weld pool surface are very different for the three conditions of pure laser welding, hybrid welding with arc leading, and hybrid welding with laser leading. The welds with arc leading are poor with deep pits and big veins while the welds with laser leading are good with a smooth surface. In LB-PAW of the 1420 Al-Li alloy, the surface formation quality of the weld is closely related to the fluid flow in the weld pool with the plasma arc force as one of the key factors. The heat source sequence is recommended to have the arc behind the laser to obtain the best weld quality.

关 键 词：激光-等离子弧复合焊 对流传热 焊缝成形 铝合金 速度场 

分 类 号：TG456.7[金属学及工艺—焊接]