摘要
为解决镀锌板QP钢板零间隙激光点焊时所产生的高压锌蒸气对焊接接头质量的影响,提出了一种以等距螺旋线为扫描路径的远程激光点焊技术,使激光光束沿此路径在焊点区域相对工件进行高速运动,形成随光束运动的稳定匙孔。激光焊接过程中,激光光束对熔池的搅拌作用会加快高压锌蒸气从熔池中逃逸;同时,稳定匙孔的生成,为高压锌蒸气提供持续、快速、稳定的逸出通道,从而获得无气孔、无裂纹且材料损失少的焊点。采用单一变量法,研究扫描速度对焊点形貌的影响,并通过高速摄像实时记录焊接过程中熔池和高压锌蒸气的动态行为,阐述了扫描速度对匙孔形成及高压锌蒸气逸出过程的影响规律,获得了抑制气孔生成和材料烧损的优化工艺参数。与传统激光点焊工艺相比,此方法可在获得满足尺寸要求的熔合面直径的同时,抑制激光点焊中常见缺陷的生成,点焊接头的平均拉剪力达到16.5kN,较传统激光点焊提高了108%。
To solve the issue of highly-pressurized zinc vapor arising from remote laser spot welding of zinc coated quench-partitioning (QP) steels, a novel remote laser spot welding technology is proposed to obtain high-quality spot welds without porosities and cracks. By designing an equidistant spiral line laser scanning path with high velocity, a stable keyhole is produced to provide a vent path for highly-pressurized zinc vapor escaping from molten pool. A single-variable method is employed to investigate the influence of scanning speed on the morphology of spot welds in QP steels. Furthermore, the dynamic behaviors of highly- pressurized zinc vapor and molten pool are real-time recorded by high-speed camera. Based on the relationship between the scanning speed of laser beam and zinc vapor behaviors, an optimized laser scanning speed is gained to avoid the formation of porosities and material loss in the welds. Compared to conventional laser spot welding, the proposed technology can suppress the formation of the weld defects in the welds and achieve the desired weld diameter. The tensile-shear strength of the welds obtained by the proposed method is 16.5 kN, which is 2.08 times higher than that of conventional laser spot welding method.
作者
张伟
林喆
陶武
杨上陆
ZHANG Wei;LIN Zhe;TAO Wu;YANG Shang-lu(Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 , China;Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China;University of Chinese Academy of Sciences, Beijing 100049, China)
出处
《现代应用物理》
2019年第2期100-105,共6页
Modern Applied Physics
基金
中国科学院“百人计划”人才项目(292017312D1100301)
关键词
激光点焊
远程激光焊接
QP钢
镀锌钢板
高压锌蒸气
零间隙搭接结构
匙孔
高速相机
laser spot welding
remote laser welding
QP steels
zinc coated steels
highly-pressurized zinc vapor
zero-gap lap configuration
keyhole
high-speed camera
