以15 mm的板厚为研究对象, 采用高氮奥氏体钢进行激光焊接, 研究气孔和裂纹对高氮钢激光焊接力学性能的影响。结果表明：在试件自然气孔率和人工气孔率分别为10.5%、12.5%时, 焊缝发生断裂; 在试件自然气孔率和人工气孔率分别为5.5%、3.5%时, 母材发生断裂。在自然气孔率为5.1%时, 气孔开始影响断裂载荷。随着自然气孔率的增加, 试件断裂载荷逐渐下降。试件伸长率随着气孔率的增加明显下降, 气孔对试件塑性的影响较大。高氮钢母材硬度为364 HV, 焊缝硬度为298 HV时, 相对于母材平均硬度下降了66 HV, 降幅达18.1%。焊接接头和母材为韧性断裂。焊缝塑性变形量要小于母材, 拉伸试验主要为正拉应力, 通过合理的焊接工艺可提高材料的强度及塑性。

The plate thickness of 15 mm was taken as the research object, the laser welding of high nitrogen austenitic steel was carried out to study the effects of air holes and cracks on the mechanical properties of laser welding of high nitrogen steel. The results show that when the natural porosity and artificial porosity of the specimens are 10.5% and 12.5% respectively, the fracture of the weld occurs. When the natural porosity and artificial porosity of the specimens are 5.5% and 3.5% respectively, the fracture of the base metal occurs. When the natural porosity is 5.1%, the porosity begin to affect the fracture load. With the increase of the natural porosity, the fracture load of the specimen decreases gradually. The elongation of the specimen decreases obviously with the increase of porosity, and the porosity has a great influence on the plasticity of the specimen. The hardness of the high nitrogen steel is 364 HV, and the hardness of the high nitrogen steel is 298 HV, and the average hardness of the high nitrogen steel is decreased by 66 HV compared with the base metal, a decrease of 18.1%. The welded joint and base metal are ductile fracture. The plastic deformation of the weld is smaller than that of the base metal. The tensile test is mainly positive tensile stress, and the strength and plasticity of the material can be improved by reasonable welding process.