Residual stress prediction for a coated tunnel boring machine cutter considering the effects of heat treatment and laser cladding

The aim of this study is to accurately predict the residual stress of a coated cutter ring by considering the effects of multiple processes, particularly heat treatment and laser cladding. To achieve this, a coupled thermal-metallurgical-mechanical (TMM) model is developed, incorporating the solid-state phase transformation (SSPT) to simulate temperature, microstructure, and stress evolution during heat treatment. The TMM model considers volume change, transformation-induced plasticity (TRIP) strain, and plastic strain caused by SSPT to represent the influence of phase transformations on the stress field. The simulation results of heat treatment are then utilized as initial conditions for a laser cladding model to assess the impact of initial heat treatment on residual stress during laser cladding. These findings reveal that the radial stress and hoop stress on the cutter ring's surface, obtained from the proposed method, align well with experimental results. The heat treatment changes the microstructure/microhardness distribution inside the cutter ring, and the residual stress causes significant differences in the stress value and distribution of the cutter ring. The maximum surface stress zone migrates from the rapid cooling area behind the molten pool to the surface away from the laser action, which may lead to changes in crack location and deformation. This work investigates the influence of microstructure features on mechanical performance, which provides technical support for predicting the deformation, wear, fatigue, and fracture behavior of coated cutter rings in real working conditions. [Display omitted] •A thermal-metallurgical-mechanical model was built considering phase transformation.•How phase transformation affects microstructure and stress during process was explored.•The effects of heat treatment and laser cladding on prediction of residual stress were elucidated.•The numerical model was verified by microstructure, microhardness and stress tests.