Fast macroscopic thermal analysis for laser metal deposition. Application to multiphase steels

Abstract

Recently, a simplified macroscopic and semi-analytical thermal analysis of Laser Meta lDeposition (LMD) has been submitted to publication. The model is fast enough to simulate the entire process. The proposed approach enables to compute: temperature, solidification and solid-state phase transitions kinetics. Process parameters, substrate characteristics and heat sources due to the enthalpy change during phase transitions are taken in to account as well as convection due to the carrying and shielding gas. The present work exploits the proposed model to investigate the influence of some process parameters in order to determine whether complex multiphase steels (such as high strength steels) could be controllably obtainedby LMD. Indeed, material properties of such steels are not only a matter of chemical composition but also and mostly a matter of phase proportions in a multiphase mixture (austenite, ferrite, pearlite, bainite and martensite). Within this framework, temperature control strategies during the process are numerically tested for a simple cylindrical geometry.