Hardness and residual stress modeling of powder injection laser cladding of P420 coating on AISI 1018 substrate

Abstract

The laser cladding process is associated with having a non-uniform material strength within the clad bead and the heat-affected zone. As well, residual stresses can develop, which in turn increase the crack driving force and reduce the strength and fatigue life of the part. In the present work, a finite element model was developed to simulate the temperature history, microhardness values, and induced residual stresses for a coaxial powder injection laser cladding process for P420 stainless steel powder on low/medium carbon steel plates. Residual stress developments for 10 single-track cladded specimens fabricated using different process parameter sets were studied by a simulation model. The model was validated with microhardness measurements and residual stress values. The effect of a heat treatment on the microhardness values and reduction of residual stress were also investigated. In the next research phase, a multi-track cladded specimen model was validated by microhardness measurements and a study was carried out on microhardness variations and residual stresses. A comparison between the simulation and experimental results exhibits the accuracy of the model to capture the laser cladding process phenomena. A well-designed simulation model can be used to determine the process parameters to avoid tensile and compressive residual stresses in the component and achieve the desired strength with more uniformity in the clad.