Microstructural evolution rule and prediction modelling of the surface layer during dry machining of AISI 9310

This paper studies the microstructural evolution rule of the surface layer created by dry turning of AISI9310 steel. In this study, a coupled model with preheated tools and the ALE (Arbitrary Lagrangian-Eulerian) method of finite element method (FEM) is established to verify the evolution rules. In order to complete the various parameters in the evolution rules, a series of tests are conducted, including thermal compression, cutting, and EBSD (Electron Back - scatter Diffraction) characterization. Based on the experimental results, a hot processing map is established to explore the grain refinement mechanism, and the critical strain condition is obtained by fitting with polynomials of different orders. Through comparison between the FEM and EBSD results, it is found that the evolution rules given in this paper can achieve a stable and uniform metallographic transformation layer and grain refinement layer, and they are consistent with the physical process of actual cutting, metal phase transformation and grain size evolution.