High Power Diode Laser (HPDL) for Fatigue Life Improvement of Steel: Numerical Modelling

Abstract

This paper deals with the improvement of fatigue life of AISI 1040 steel components by using a High Power Diode Laser (HPDL). First, the meaningfulness of each operational parameter was assessed by varying the experimental laser power and scan speed. After laser treatment, fatigue tests were performed to investigate the influence of laser processing parameters on the material resistance. The fatigue tests were carried out by using a rotating bending machine. Wöhler curves were obtained from the analysis of experimental results. Second, in the light of experimental findings, a 3D transient finite element method for a laser heat source, with Gaussian energy distribution, was developed to predict the temperature and the depth of the heat affected zone on the workpiece. The model allows us to understand the relationship between the laser treatment parameters and the fatigue enhancement of the components. HPDL was found to significantly increase the fatigue life of the irradiated workpieces, thus revealing its suitability for industrial applications.

Adaptive thermal model for real-time peak temperature and cooling rate prediction in laser material processing

“…In addition, the prediction accuracy, with most experiments, is within the thermal camera accuracy of 1%. This prediction accuracy is a significant improvement compared to the peak temperature prediction accuracy between 3.5% and 7% found in literature [9,[44][45][46]. Furthermore, the cooling rate prediction accuracy of the adaptive thermal model is between 1.4% and 15.0%.…”

“…The peak temperature prediction accuracy is between 1.2% and 6.1%. In comparison, other researchers state that their thermal models predict the peak temperature of the LHT process with an accuracy between 3.5% and 7% [9,[44][45][46]. Hence, the prediction accuracy of the thermal model developed in Chapter 3, even without adaptation, is already better compared to these other models.…”

Comparison of Effects of Laser, Ultrasonic, and Combined Laser-Ultrasonic Hardening Treatments on Surface Properties of AISI 1045 Steel Parts

“…The laser transformation hardening process consists of high-speed local heating of the surface layer by a laser beam above critical temperature points for the austenitic structure formation and subsequent rapid cooling of the treated surface using heat transfer in the inner layers of the material [4,12]. As a consequence, the fine-grained martensitic structure is formed due to phase transformations, which are characterized by a high wear resistance for AISI 1045 steel [13], R260 grade rail steel [14], and AISI 8620 steel [15], corrosion resistance for AISI 1045 steel [16], and fracture resistance for AISI 1040 steel [17]. It should also be noted that the martensiticaustenitic structure formation depends on the laser surface hardening regimes and the carbon concentration in the alloy.…”

An Optimal Genetic Algorithm for Fatigue Life Control of Medium Carbon Steel in Laser Hardening Process

“…In this context, the development of predictive models appears to be a virtual solution in order to reduce time and costs in finding the optimal operational process conditions. To this end, many research studies have focused on the development of relationships between process parameters and process responses [21][22][23]. Thus, research in laser hardening process development, optimization, modelling and simulation plays a critical role in advancing surface engineering science and technology [24].…”