Fiber laser welding of QP980 steel and press-hardened 22MnB5 steel in butt configuration was performed in this study. The effect of heat input on microstructure evolution and mechanical properties of dissimilar joint was investigated. Laser power employed was varied from 1.6 to 2.4 kW while welding speed was kept constant at 2 m/min. The microstructure of fusion zone (FZ) was changed with the increasing laser power. Martensite and few bainite were observed when laser power ranged from 1.8 to 2.2 kW. Out of this range, the microstructure in FZ consisted of mixed structure of martensite and ferrite. Transformation from liquid phase to ferrite was promoted by Al-Si coating on the surface of press-hardened 22MnB5 steel. Heat affected zones (HAZs) of dissimilar joint were composed of martensite and bainite. Softened zone (SZ) appeared at the HAZ of 22MnB5 steel due to tempering behavior. The hardness of SZ and QP980 steel base metal declined with microstructure evolution. The fracture occurred at QP980 base metal when dissimilar joints were produced at laser power of 1.8 and 2.0 kW. When laser power reached 2.2 kW, the tensile samples failed at SZ owing to the increased softening degree. With further increasing laser power, the weakest region was FZ since ferrite declined the whole joint strength. A better Erichsen value was obtained at 2.0 kW (4.04 mm), which was balanced by more crash energy absorption and better deformation resistance.

在这项研究中，对接结构是对QP980钢和加压淬火的22MnB5钢进行光纤激光焊接。研究了热量输入对异种接头组织演变和力学性能的影响。使用的激光功率从1.6到2.4 kW不等，而焊接速度保持恒定在2 m / min。随着激光功率的增加，熔化区（FZ）的微观结构发生了变化。当激光功率在1.8至2.2 kW之间时，观察到马氏体和少量贝氏体。在此范围之外，FZ的显微组织由马氏体和铁素体的混合结构组成。通过在加压硬化的22MnB5钢表面上进行Al-Si涂层促进了从液相到铁素体的转变。异种接头的热影响区（HAZs）由马氏体和贝氏体组成。由于回火行为，在22MnB5钢的热影响区出现软化区（SZ）。SZ和QP980钢母材的硬度随着组织的发展而降低。当在1.8和2.0 kW的激光功率下产生异种接头时，断裂发生在QP980母材上。当激光功率达到2.2 kW时，由于软化程度的提高，拉伸样品在SZ失效。随着激光功率的进一步提高，最弱的区域是FZ，因为铁素体降低了整个接头强度。在2.0 kW（4.04 mm）时获得了更好的Erichsen值，这可以通过吸收更多的碰撞能量和更好的抗变形性来平衡。当在1.8和2.0 kW的激光功率下产生异种接头时，断裂发生在QP980母材上。当激光功率达到2.2 kW时，由于软化程度的提高，拉伸样品在SZ失效。随着激光功率的进一步提高，最弱的区域是FZ，因为铁素体降低了整个接头强度。在2.0 kW（4.04 mm）时获得了更好的Erichsen值，这可以通过吸收更多的碰撞能量和更好的抗变形性来平衡。当在1.8和2.0 kW的激光功率下产生异种接头时，断裂发生在QP980母材上。当激光功率达到2.2 kW时，由于软化程度的提高，拉伸样品在SZ失效。随着激光功率的进一步提高，最弱的区域是FZ，因为铁素体降低了整个接头强度。在2.0 kW（4.04 mm）时获得了更好的Erichsen值，这可以通过吸收更多的碰撞能量和更好的抗变形性来平衡。