随着核电工业的发展，对厚板不锈钢的焊接要求越来越高，传统的弧焊方法效率低、变形大、组织粗大、抗核辐照性能差，难以满足使用要求。采用3500 W Slab及20 kW快轴流CO₂激光器，研究了厚板万瓦级激光自熔焊接、窄间隙激光填丝焊接及激光-钨极氩弧焊（TIG）填丝复合焊接，实现了厚度超过10 mm的不锈钢对接焊，并对接头的显微组织和力学性能进行了研究。结果表明，激光焊接可以获得焊缝成型良好，无气孔、裂纹等缺陷的焊接接头；焊缝组织细小，热影响区窄，接头显微组织和力学性能优良。

With the development of nuclear power industry, the heavy section stainless steel vacuum vessel presents many challenges to joining methods. The conventional welding processes can’t satisfy the strict accuracy and quality requirements due to its higher heat input. In this paper, a 3500 W Slab CO₂ laser and a 20 kW fast axial flow CO₂ laser were applied to weld austenitic stainless steels with a plate thickness over 10 mm. The autogenous laser welding, narrow gap laser welding with filler wire and laser-tungsten inert gas (TIG) hybrid welding with filler wire were exploited respectively. Meanwhile, the joint microstructure and properties were studied. The experimental results shown that welds with good appearances and no holes and cracks could be obtained with laser beam welding techniques, and the joint microstructures and properties are satisfied with the service requirements.