In this paper, fiber laser butt welding on the dissimilar joint between reduced-activation ferrite/martenstic CLF-1 steel and 316 L stainless steel with a thickness of 10 mm was performed. Furthermore, the mechanical properties, microstructure, and phase of the joints before and after post welding heat treatment (PWHT) were investigated and the evolutionary mechanism of microstructure was explored in combination with temperature field simulation and element distribution characteristics. As the beam action position was shifed from CLF-1 to 316 L base, the mount of martensite phase in the weld dropped, and the mount of austenite phase increased gradually. As the laser beam offset toward the 316 L by 0.35 mm, the weld was composed mainly of austenite phase, and simultaneously, the microhardness of the weld zone significantly dropped. As the laser beam offset toward the 316 L by 0.2 mm, three phases, namely, austenite, martensite, and ferrite, co-existed in the weld, which according to the prediction results of the Schaeffler-Schneider diagram. After PWHT at 710 °C for 2 h, the content of residual austenite increased and M₂₃C₆ was precipitated at the boundary of martensite lash. The microhardness of the weld zone dropped from 437.3 HV under the as-welded condition to 307.3 HV, and the mean impact absorbed energy was enhanced from 130 J to 169 J.

本文对减活化铁素体/马氏体CLF-1钢与厚度为10 mm的316 L不锈钢之间的异种接头进行了光纤激光对接焊接。此外，还研究了焊接后热处理（PWHT）前后接头的力学性能，显微组织和相，并结合温度场模拟和元素分布特征探索了显微组织的演变机理。随着束作用位置从CLF-1转变为316 L，焊缝中的马氏体相减少，奥氏体相逐渐增加。当激光束向316 L方向偏移0.35 mm时，焊缝主要由奥氏体相组成，同时，焊缝区的显微硬度明显降低。根据Schaeffler-Schneider图的预测结果，当激光束向316 L偏移0.2 mm时，奥氏体，马氏体和铁素体这三个相共存。在710°C下进行2小时的PWHT处理后，残余奥氏体含量增加并且M₂₃ C ₆在马氏体间隙处析出。焊接区的显微硬度从焊接时的437.3 HV下降到307.3 HV，平均冲击吸收能从130 J提高到169J。