Publication

Abstract :

Laser surface hardening, when applied to complex geometries, poses a challenge in the terms of obtaining uniform hardness throughout the hardened area because of variable heat sink effects. In this work, an iterative numerical approach was used to estimate the required modulation in laser power to achieve a uniform surface temperature throughout the process zone. Firstly, a transient thermal model for the laser–material interaction was developed using the finite element method for a rectangular spot of 8 × 5 mm. The temperature-dependent material properties were used to bring in nonlinear effects in the analysis so as to predict the hardened zone dimensions more precisely. The numerical model was validated by carrying out laser hardening experiments using a 6-kW diode laser. The validated numerical model was used with an iterative technique aided by conditional looping to achieve a uniform surface temperature during the laser hardening of the complex geometry with a variable heat sink. The developed iterative approach can be effectively used on any geometry with a variable heat sink to obtain a constant surface temperature throughout the process zone. Copyright © 2019 by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959