Considering cyclic plasticity to predict residual stresses in laser cladding of Inconel 718 multi bead samples

Abstract

A thermo-mechanical finite element model is developed to accurately predict residual stresses of the multiple beads laser cladding process, incorporating the cyclic plasticity into the analysis by utilizing the nonlinear kinematic hardening behavior. Finite Element results are presented for Inconel 718, a material for which the laser cladding process is widely used. The FE results are compared with the results of incremental center hole drilling conducted on three specimens with different clad beads to evaluate the effect of cyclic plasticity modeling on the residual stresses. The results indicate that incorporating the nonlinear kinematic hardening model into the analysis can reduce the difference between its estimated residual stresses and the experimental results by about fifty percent comparing with the analyses without considering the kinematic hardening. The results also indicate that the nonlinear cyclic plasticity modeling provides the opportunity to capture important phenomena of hardening and stress relaxation in the laser cladding process.