Author(s)

Rachid Fakir^1,2, Noureddine Barka¹, Jean Brousseau¹, Gabriel Caron-Guillemette²

¹Département de mathématiques, informatique et génie, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, QC, Canada.
²Bombardier Transport Canada Inc., La Pocatière, Québec, Canada.

This paper presents a numerical and experimental analysis study of the temperature distribution in a cylindrical specimen heat treated by laser and quenched in ambient temperature. The cylinder studied is made of AISI-4340 steel and has a diameter of 14.5-mm and a length of 50-mm. The temperature distribution is discretized by using a three-dimensional numerical finite difference method. The temperature gradient of the transformation of the microstructure is generated by a laser source Nd-YAG 3.0-kW manipulated using a robotic arm programmed to control the movements of the laser source in space and in time. The experimental measurement of surface temperature and air temperature in the vicinity of the specimen allows us to determine the values of the absorption coefficient and the coefficient of heat transfer by convection, which are essential data for a precise numerical prediction of the case depth. Despite an unsteady dynamic regime at the level of convective and radiation heat losses, the analysis of the averaged results of the temperature sensors shows a consistency with the results of microhardness measurements. The feasibility and effectiveness of the proposed approach lead to an accurate and reliable mathematical model able to predict the temperature distribution in a cylindrical workpiece heat treated by laser.

Laser Hardening, Scanning Speed, Case Depth, Finite Difference Method, AISI-4340

Fakir, R. , Barka, N. , Brousseau, J. and Caron-Guillemette, G. (2018) Numerical Investigation by the Finite Difference Method of the Laser Hardening Process Applied to AISI-4340. Journal of Applied Mathematics and Physics, 6, 2087-2106. doi: 10.4236/jamp.2018.610176.