为了提高车用超高强钢激光焊接技术的发展，采用光纤激光器对1.9 mm厚的22MnB5钢板进行激光对焊以及22MnB5与Q235钢板的激光拼焊。研究了激光焊接接头的微观组织、硬度以及拉伸性能的变化，分析了焊接速度对接头组织、性能的影响。结果表明，22MnB5钢焊缝组织主要是板条马氏体，22MnB5热影响区可分为完全淬火区、不完全淬火区和回火区，而Q235热影响区不存在回火区。焊接接头硬度分布不均匀，在焊缝边缘硬度最高。热影响区很窄，硬度急剧下降，22MnB5热影响区存在严重的软化区，最低硬度仅为319.6 HV，Q235热影响区不存在软化区。随着焊接速度的增加，焊缝组织变得细小，马氏体含量增多，当焊速达到5 m/min时，22MnB5焊缝最高硬度达到544.2 HV。在垂直于焊缝的负载下，焊接速度为3~5 m/min时，22MnB5拉伸试样均断裂在热影响区，塑性较差，断后延伸率仅为2%左右，而母材的断后延伸率却达到了8.9%。

To accelerate the development of the laser welding technology of advanced high strength steel (AHSS), similar butt welding of 1.9 mm thick 22MnB5 and dissimilar tailored blank welding of 22MnB5 and Q235 are performed by using a fiber laser. The microstructure, hardness and tensile properties of weld joints are analyzed after the fiber laser welding (FLW). The results show that the microstructure of weld zone(WZ) mainly contains lathy martensite. Heat affected zone (HAZ) in 22MnB5 can be divided into three parts: quenched zone, incomplete quenched zone and tempered zone, and the last one is absent in Q235. The hardness distribution of weld joints is non-uniform, and the weld edge has the highest hardness. HAZ is very narrow and a soft zone exists in the 22MnB5 HAZ with the lowest hardness of 319.6 HV, while there is no soft zone in Q235. With the increase of welding speed, the martensite in WZ becomes finer, leading to the increasing of hardness. When the welding speed is 5 m/min, the highest hardness of the WZ attains 544.2 HV which is the highest of all the samples. The 22MnB5 samples for tensile test which are welded at the speed from 3 to 5 m/min are all broken in HAZ, and the elongation at break is only about 2%, which is obviously worse than that of base metal (8.9%).