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研究了不锈钢锻件在变形过程中的组织演变规律和裂纹形核与扩展机理,采用应力三维度法对锻件断裂破坏过程进行研究。结果表明,在热拉伸过程中不锈钢锻件的裂纹产生主要是经过裂纹形核、长大和聚集过程,变形过程中缩颈区域的显微孔洞更倾向于在晶界处产生。单向拉伸过程中,应力三轴度在越靠近心部的区域越大,则孔洞或者微裂纹越容易形成断裂。采用应力三轴度法可以准确判断不锈钢锻件在高温变形过程中的裂纹萌生和扩展过程,对于预测不锈钢锻件在高温锻造过程中损伤破坏过程具有重要的作用。
The microstructure evolution and crack nucleation and propagation mechanism of stainless steel forgings during deformation were studied. The three-dimension stress method was used to study the fracture and failure process of forgings. The results show that the cracks in the stainless steel forgings mainly form nucleation, growth and aggregation during the hot drawing process. The micro-cavities in the necking region tend to be generated at the grain boundaries during the deformation. Uniaxial stretching process, the stress triaxiality in the area closer to the heart of the larger, then the hole or micro-cracks more easily fracture. The stress triaxiality method can accurately determine the initiation and propagation of cracks in the process of high temperature deformation of stainless steel forgings and plays an important role in predicting the damage process of stainless steel forgings during the high temperature forging process.