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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。
The filling hot wire is applied to the narrow gap welding of the fiber laser with high beam quality and long focal length. The stainless steel base material is heated by the laser and the nickel-based welding wire is heated by the electric current to effectively utilize the advantages of the composite heat source, thereby improving the transition stability and cladding effectiveness. Through the high-speed camera on-line process of online observation, analysis of process parameters on the wire transition. Studied the solidification microstructure of stainless steel and nickel-base alloy dissimilar metal narrow gap welded joint, and carried out the elemental distribution scanning of the weld metal. It is found that the wire feeding stability, which is determined by parameters such as wire current and wire feed speed, is the most important factor that affects the quality of laser wire welding. For narrow gap welding, laser thermal welding with defocus spot laser with the same gap width can form better sidewall fusion. The laser reflection formed by the molten metal surface and the sidewall is the main reason for sidewall fusion. Weld cooling faster, solidified microstructure of the weld metal was obvious growth, near the bevel in the growth direction and the sidewall perpendicular to the vertical, the weld does not exist macro-segregation. At the bottom of the gap at the right angle prone to unmelted phenomenon, the use of the bottom of the U-shaped groove transition arc, the bottom can be a good solution to the problem of unmelted, obtained without macro-defect welded joints.