摘要激光+MIG复合焊是一种新型的焊接方法，其不仅融合了激光焊、MIG焊的优点，同时也克服了激光焊工件装配间隙要求高以及MIG效率低的缺点。本试验采用激光+MIG复合焊的焊接方法，对8mm板厚的A304不锈钢进行焊接工艺试验，研究了焊接工艺参数对焊缝成形的基本规律，为激光+MIG复合焊焊接技术的广泛使用提供了必要的试验依据；研究了复合焊焊接接头的微观组织与力学性能，并与激光焊、MIG焊进行了对比。研究结果表明：与MIG焊相比，复合焊焊接方法更容易实现良好的焊缝成形；激光功率是影响复合焊熔深的重要参数，而MIG焊焊接电流主要决定复合焊焊缝的熔宽。多次试验得到了优化参数：激光功率为5kW，MIG焊电流为250A，光丝间距为2mm，离焦量为-5mm，焊接速度为1。6m/min。在高速焊接条件下，复合焊焊接速度与MIG焊焊接速度相比，复合焊速度提高约4倍。在焊接接头的微观组织方面，熔合区上部区域的组织比下部区域粗大，熔合区下部的组织中很少出现柱状晶，熔合区中部的柱状晶比熔合区上部的柱状晶更密、间距更小；无论处于焊缝上部、中部及下部，焊缝中心硬度值不低于母材，焊缝中心上部的硬度值小于焊缝中心的中、下部；焊缝的抗拉强度平均值能达到母材抗拉强度的96%；装配间隙越大，抗拉强度值越小。以上研究表明，激光+MIG复合焊比激光焊、MIG更为优越。86171

毕业论文关键词：复合焊；不锈钢；工艺参数；力学性能

Abstract Laser +MIG hybrid welding is a new kind of welding method, which not only incorporates the advantages of traditional laser welding, MIG welding, as well as overcomes the laser welder assembly clearance requirement and the shortcomings of low efficiency of MIG welding。 This experiment uses the laser +  MIG hybrid welding method, to 8 mm thickness of A304 stainless steel welding technology experiment, studied the welding process parameters on the weld, the basic rules of laser + MIG hybrid welding technology widely used provides the necessary test basis。 Studied the hybrid welding joint microstructure and mechanical properties, and compares with the laser welding and MIG welding。 The results show that: compared with the MIG welding, hybrid welding method is easier to achieve a good weld forming; Laser power are the important parameters of compound welding penetration, and the MIG welding current is mainly decided compound weld fusion width。 Many experiments to get the optimized parameters: the laser power is 5 kW, the MIG welding current is 250 A, light wire spacing for 2 mm, to -5 mm from the coke quantity, the welding speed of 1。6 m/min。 Under the condition of high speed welding, hybrid welding speed compared with MIG welding speed, the hybrid speed increased about 4 times。 In the microstructure of welded joint, the fusion zone of the upper area of the organization than the lower region is bulky, the fusion zone of the lower organizations rarely appears in the columnar crystal, the middle of fusion zone’s columnar crystal than the upper part of the fusion zone is more dense, and the spacing is more smaller。 Whether it is in the upper, middle and lower welds, weld center hardness values are not lower than the parent metal, the hardness of weld center of the upper value is less than lower part of the center of the weld, Average tensile strength of weld to achieve 96% of the parent metal tensile strength, As the assembly clearance increases, weld tensile strength decrease。 Above studies show that the laser + MIG hybrid welding is more superior than  laser welding, and MIG welding 。

Keywords: hybrid welding; stainless steel; process parameters; properties of Mechanical

目     录

第一章  绪论 1

1。1课题研究的背景及意义