在侧吹纯氦气后侧添加纯氩气保护的条件下, 对5 mm 厚R60702锆材进行CO2激光焊接, 并采用光学显微镜、X射线探伤仪、拉伸试验机和显微硬度计研究了焊接接头的显微组织和力学性能。结果表明: 在保护气最佳流量配比的条件下, 焊缝为淡黄色, 没有气孔、裂纹等焊接缺陷, 满足工业焊道气保护的要求; 接头母材组织为等轴α相, 焊缝区组织为针状α′马氏体, 热影响区为板条马氏体和针状马氏体; 焊缝和母材的显微硬度分别约为200, 155 HV, 显微硬度从焊缝向母材逐渐降低; 焊接接头焊缝的抗拉强度高于母材的。

CO2 laser welding was used to weld zirconium plates of 5 mm thickness under the condition of additional protective gas being setbehind the side-blown gas, and the microstructure and mechanical properties of welded joint were studied by optical microscopy(OM), X-ray flaw detector, tensile testing and microhardness measuring. The results show that the weld seam was faint yellow without obvious porosity and crack, and met the gas shielding requirements for industry. The microstructure of the base metal, weld seam and heat affected zone were equiaxed α phase, needle α′ martensites and lath and needle martensites, respectively. The microhardness of the weld seam zone and base metal were 200 HV and 155 HV , respectively, and the microhardness decreased with the distance from the weld seam to the base metal. The tensile strength of weld seam was higher than that of base metal.