高强度钢正交切削过程中剪切变形局部化研究

通过正交切削实验对高强度钢30CrNi3MoV锯齿形切屑内剪切变形局部化的临界切削条件和绝热剪切带的分布规律以及微结构特征进行了研究．结果表明，因切屑剪切区内发生剪切变形局部化，在一定临界切削速度下切屑由带状屑转变为锯齿形切屑；对临界切削速度的理论预测和实验结果基本一致．随着切削速度的增加，剪切带的宽度和间距随之减小．在锯齿形切屑内发现两种剪切带即形变剪切带和白色剪切带．TEM观察表明，白色剪切带中心为等轴晶粒，剪切带内的组织结构经历了一系列复杂的演变过程．

Research on shear deformation localization in high-strength steel during orthogonal cutting

The critical cutting conditions of shear deformation localization, distributing laws and microstructures of adiabatic shear band in the serrated chips of high-strength steel 30CrNi3MoV are investigated by orthogonal cutting. The results show that the ribbon chips shift to the serrated chips at a certain critical cutting speed because of the occurrence of shear deformation localization in chip shear zones, which is in agreement with the theoretical prediction of the critical cutting speed, and that the shear band width and spacing gradually decrease with the increasing of the cutting speed. Two types of shear bands, i.e. deformed shear bands and white shear bands, are observed in the serrated chips. TEM observations reveal the equiaxed grains in the center of the white shear bands, and the microstructures in shear bands undergo a series of complicated evolution processes.