TITLE:
Numerical Investigation of Laser Surface Hardening of AISI 4340 Using 3D FEM Model for Thermal Analysis of Different Laser Scanning Patterns
AUTHORS:
Baha Tarchoun, Abderrazak El Ouafi, Ahmed Chebak
KEYWORDS:
Laser Surface Hardening, 3D Thermal Analysis, Finite Element Modelling, AISI 4340 Steel, Laser Scanning Patterns, Taguchi Method, ANOVA, Nd:Yag Laser Source
JOURNAL NAME:
Modeling and Numerical Simulation of Material Science,
Vol.10 No.3,
July
17,
2020
ABSTRACT: Laser surface hardening is becoming one of the most
successful heat treatment processes for improving wear and fatigue properties
of steel parts. In this process, the heating system parameters and the material
properties have important effects on the achieved hardened surface
characteristics. The control of these variables using predictive modeling
strategies leads to the desired surface properties without following the
fastidious trial and error method. However, when the dimensions of the surface
to be treated are larger than the cross section of the laser beam, various
laser scanning patterns can be used. Due to their effects on the hardened
surface properties, the attributes of the selected scanning patterns become
significant variables in the process. This paper presents numerical and
experimental investigations of four scanning patterns for laser surface
hardening of AISI 4340 steel. The investigations are based on exhaustive
modelling and simulation efforts carried out using a 3D finite element thermal
analysis and structured experimental study according to Taguchi method. The
temperature distribution and the hardness profile attributes are used to
evaluate the effects of heating parameters and patterns design parameters on
the hardened surface characteristics. This is very useful for integrating the
scanning patterns’ features in an efficient predictive modeling
approach. A structured experimental design combined to improved statistical
analysis tools is used to assess the 3D model performance. The experiments
are performed on a 3 kW Nd:Yag laser system. The modeling results exhibit a
great agreement between the predicted and measured values for the hardened
surface characteristics. The model evaluation reveals also its ability to provide not only accurate and
robust predictions of the temperature distribution and the hardness profile as
well an in-depth analysis of the effects of the process parameters.