中国激光, 2011, 38 (11): 1103004, 网络出版: 2011-10-24
填充热丝激光窄间隙焊接的实验研究 下载: 519次
Experimental Research on Laser Narrow Gap Welding with Filling Hot Wire
激光技术 激光焊接 热丝 高速摄像 窄间隙焊接 laser technique laser welding hot wire high speed imaging narrow gap welding
摘要
将填充热丝应用到高光束质量、长焦距的光纤激光窄间隙焊接中,不锈钢母材通过激光加热,镍基焊丝通过电流加热,有效利用复合热源的优势,提高了焊丝过渡稳定性和熔覆效率。通过高速摄像机对送丝过程进行在线观察,分析工艺参数对焊丝过渡的影响。研究不锈钢和镍基合金异种金属窄间隙焊接接头的凝固组织,并对焊缝金属进行元素分布扫描。研究发现,由焊丝电流和送丝速度等工艺参数决定的送丝稳定性是影响填充热丝激光焊接质量的最主要因素。对于窄间隙焊接,采用与间隙宽度相当的离焦光斑激光热导焊,可形成较好的侧壁熔合,由熔融金属曲面和侧壁构成的激光反射是侧壁熔合的主要原因。焊缝冷却速度较快,焊缝金属的凝固组织呈明显的对生生长,在坡口侧壁附近其生长方向与侧壁近似垂直,焊缝不存在宏观偏析。在间隙底部直角处容易出现未熔合现象,采用底部圆弧过渡的U型坡口后,可较好地解决底部未熔合问题,获得了无宏观缺陷的焊接接头。
Abstract
Hot wire is used as the filler metal of high beam quality and long focal distance fiber laser for narrow gap welding. The austenite stainless steel base metal is molten by laser, and the Ni-based alloy wire is heated up by wire current. Both the stability and efficiency are improved a lot by using the hybrid heating sources. High speed camera is used to observe the movement of filler wire during laser welding and analyze the effect of welding parameters on wire transition. The solidification microstructure and the element distribution of narrow gap laser weld are studied. Consequently, it is found that wire current and filling wire speed are the two key processing parameters for laser hot wire welding quality. The side wall of base metal is bonded well with weld metal when defocused laser spot with a diameter close to the width of narrow gap is used. The laser reflection mainly contributes to the melting of side walls, rather than the laser beam itself. The solidification microstructure shows obvious epitaxial growth, while the dendrites grow vertically to the side wall due to the rapid cooling speed. No macro segregation is found. However, lack of fusion is found in the bottom of narrow gap with a 90° angle. This problem is solved by using U type narrow gap with arc transition in the bottom. The narrow gap laser weld is finally obtained without macro weld defects.
温鹏, 郑世卿, 荻崎贤二, 山本元道. 填充热丝激光窄间隙焊接的实验研究[J]. 中国激光, 2011, 38(11): 1103004. Wen Peng, Zheng Shiqing, Shinozaki Kenji, Yamamoto Motomichi. Experimental Research on Laser Narrow Gap Welding with Filling Hot Wire[J]. Chinese Journal of Lasers, 2011, 38(11): 1103004.