激光深熔焊接的熔池行为与焊接缺陷的研究.doc

激光深熔焊接的熔池行为与焊接缺陷的研究
 
郑启光辜建辉王涛王忠柯陶星之段爱琴
摘要:分析了激光深熔焊接的小孔机制的数学模型。研究了焊接熔池的稳定性与金属蒸气压的关系及金属蒸气压与等离子体的关系。着重研究了激光焊接工艺参数(包括激光模式、功率、聚焦条件、焊接速度和辅助吹气)对焊接熔池行为的影响,最后,还研究了熔池行为与焊缝组织结构和缺陷(如气孔、裂纹等)的关系。
关键词:激光深熔焊接熔池稳定性金属蒸气反冲压气孔
Investigation on melting pool behavior and defects of laser welding
 
Zheng Qiguang,Gu Jianhui,Wang Tao,Wang Zhongke,Tao Xingzhi
(National Laboratory of Laser Technology,HUST,Wuhan,430074)
Duan Aiqin
(High Energy Beam Processing Laboratory of National Defense)
Abstract:In this paper,a mathematical model of keyhole mechanism of laser deep welding has been studied the relationship of the stability of weld pool with metallic vapor pressure and the relationship of metallic vapor with effect of laser weld parameters(including laser mode,laser power,focusing condition,welding speed and assistant gas etc.)on weld pool behavior have been investigated in ,we also have analyzed the weld pool behavior related weld structure and defects(such as crack and porosity etc.).
Key words:laser deep ration weld stability of melt pool metal vapor recoil pressure porosity
 
引言
 
激光深熔焊接的本质特征为小孔效应。当高功率密度激光束入射到金属表面时,材料被迅速加热,由于热传导作用,材料将产生熔化、蒸发。如果材料蒸发速度足够高,激光束将在金属中打出一个小孔,在小孔内,金属蒸气反冲压力与液态静压力、表面张力之间的作用的动态平衡将维持小孔的存在[1]。小孔内的蒸气压力分布和有关的气体动力学及离化作用将影响到小孔的形状。在激光深熔焊接中,由于存在小孔,激光束能深入到材料内部,被熔化的液态金属环绕在小孔的周围,激光对材料的热输入主要是在小孔壁上的液化界面上,随着激光束的移动,小孔前沿的金属被熔化、汽化,而在小孔后部,