TITLE:
Numerical Investigation by the Finite Difference Method of the Laser Hardening Process Applied to AISI-4340
AUTHORS:
Rachid Fakir, Noureddine Barka, Jean Brousseau, Gabriel Caron-Guillemette
KEYWORDS:
Laser Hardening, Scanning Speed, Case Depth, Finite Difference Method, AISI-4340
JOURNAL NAME:
Journal of Applied Mathematics and Physics,
Vol.6 No.10,
October
26,
2018
ABSTRACT: 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.