Finite-element simulation of melt pool geometry and dilution ratio during laser cladding

Abstract

To analyze the influence of processing conditions on the melt pool geometry and dilution ratio of the Ni-based alloy during laser cladding, a finite element model of heat transfer and fluid flow with multi-physical parameters was established. This model is used to simulate the temperature and velocity fields of melt pool. Thermodynamic processes such as phase transition, Marangoni convection and buoyancy were considered in this model. Adding materials in real time was considered by introducing powder feeding rate. The relative energy–mass ratio (REMR) was introduced to simplify process analysis, and the effects of different processing parameters on the dilution rate and on the melt pool geometry were explored through the established model. The results show that dilution ratio and REMR are linearly related within a certain range. In addition, due to the fluid flow, the boundary at bottom of melt pool changes gradually from shallow arc shape to wave shape, and finally to deep arc shape with increased REMR.