精冲零件断面质量及变形区显微状态的研究

Quality of cut surface and micro state in deformation zone of fine blanked part

借助于有限元分析软件DEFORM-3D,建立了非回转体三维热力耦合有限元模型,对精冲零件进行了模拟分析.随后利用精冲试验得到精冲零件,并通过观测精冲零件断面,对精冲件的不同特征部位断裂带大小、变形区的流线、晶粒变形和显微硬度进行了观测和分析.此外,采用电子探针显微分析仪分析了断裂区的化学成分.通过以上研究发现:直线和圆弧特征部位的精冲性能相当,内凹特征部位的精冲性能最好;精冲变形区流线密集,而零件心部流线稀疏;精冲零件主要剪切变形区有明显的冷作硬化现象,主要变形区硬度最大值较基体硬度提高了约90%;精冲变形过程中发生了化学成分的迁移,断裂区有害元素P,S和Si含量增多,有益元素Mn,Cu和Fe含量减少,促进了剪切面断裂带的形成.

A non-rotary three-dimensional coupled thermal-mechanical model was established to analyze a fine blanked part based on finite element analysis software DEFORM-3D.By observing the cut surface of fine blanked part after fine blanking test,the length of cracked surface at different features,streamline,grain deformation and micro hardness in the deformation zone of the fine blanking part were analyzed.Additionally,the chemical composition within the fracture zone was analyzed by using electron probe micro analyzer.The following conclusions can be drawn：the forming performances of linear feature and circular arc feature are similar,both of them being worse than that of concave feature;streamlines are assembled in the deformation zone,and streamlines in the center of part are sparse;work hardening exhibits obvious in the mainly shear deformation zone of the fine blanking part,and maximum value of hardness in the deformation zone is 90% higher than that in the matrix;the migration of chemical composition occurs in the process of fine blanking.The increase of harmful elements P,S and Si as well as the reduction of the beneficial elements Mn,Cu and Fe in the fracture zone promotes the formation of shear fracture.