Physics Based Microstructure Simulation for Drilled Hole Surface in Hardened Steel

Abstract

For a fully hardened steel material, hole surface microstructures are often subject to microstructural transition because of the intense thermomechanical loading. A white layer can be formed on the surface of a drilled hole of hardened carbon steels, which results from two mechanisms: thermally driven phase transformation and mechanical grain refinement due to severe plastic deformation. In this study, a multistep numerical analysis is conducted to investigate the potential mechanism of surface microstructure alterations in hard drilling. First, threedimensional (3D) finite element (FE) simulations are performed using a relative coarse mesh with advantedge for hard drilling of AISI 1060 steel to achieve the steadystate solution for thermal and deformation fields. Defining the initial condition of the cutting zone using the 3D simulation results, a multiphysics model is then implemented in twodimensional (2D) coupled Eulerian–Lagrangian (CEL) FE analysis in abaqus to model both phase transformation and grain refinement at a fine mesh to comprehend the surface microstructure alteration. Experimental results are used to demonstrate the capability of this multiphysics model to predict critical surface microstructural attributes.