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以15mm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298HV时,相对于母材平均硬度下降了66HV,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。
Taking 15mm thick as the research object, laser welding was performed on high-nitrogen austenitic steel to study the influence of pores and cracks on the mechanical properties of high-nitrogen steel laser welding. The results show that the weld fracture occurs when the natural porosity and the artificial porosity of the specimen are 10.5% and 12.5%, respectively. When the natural porosity and the artificial porosity of the specimen are respectively 5.5% and 3.5%, the base metal is fractured . At natural porosity of 5.1%, the pores begin to affect the fracture load. With the increase of natural porosity, the fracture load of specimens decreases gradually. Elongation rate of specimens decreased obviously with the increase of porosity, and the influence of stomata on the plasticity of specimens was greater. High nitrogen steel base metal hardness of 364 HV, the weld hardness of 298HV, relative to the average hardness of the base metal decreased by 66HV, a decrease of 18.1%. Welded joints and base metal are ductile. Plastic deformation of the weld is less than the base metal, tensile test mainly positive tensile stress, through a reasonable welding process can improve the strength and plasticity of the material.