A pragmatic approach for assessment of laser-induced compressive residual stress profiles

Fischer, Andreas; Dewi, Handika Sandra; Volpp, Jöerg; Tranchero, Jacobo Otero; Arias, J.L.; Grela, Javier Souto; Köcher, David; Krooß, P.; Kaplan, Alexander; Niendorf, Thoralf

doi:10.1016/j.jmapro.2021.05.063

Cited by 3 publications

(1 citation statement)

References 28 publications

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“…In 2021, Han et al 10 did a numerical simulation of the thermal–force coupling during the laser quenching for the SUS301L-HT stainless steel, and studied the effect of grain inhomogeneity on the distribution for quenching stresses. In the same year, Fischer et al 11 established a prediction method of residual stress through multiple experiments and accurately evaluated the surface residual stress. Although a large amount of research has been conducted on laser quenching, most of them is focused on the characterization for terminal materials, and cannot obtain the coupling effects and transient laws of multiple physical fields during the quenching.…”

Section: Introductionmentioning

confidence: 99%

Optimization of laser irradiation process parameters for 40Cr steel based on back propagation neural network and genetic algorithm

Chang

Deng

Sun

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part L:

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40Cr is a significant material in the manufacturing of gears. However, this process is plagued by uneven distribution of quenching layers and excessive residual stress, leading to a decline in the precision of the workpiece, deformation, and cracking. Relying solely on the trial-and-error method in experiments is inadequate for effectively revealing the evolution mechanism of the laser quenching process. This approach is detrimental to improving research and development efficiency. In this study, a multi-field coupled numerical model for the multi-track overlapping laser quenching of the 40Cr gear steel is established. This model quantitatively reveals the coupling evolution laws of the temperature field, stress field, and phase transformation field during the laser quenching. The focus is on calculating the size of the tempering zone under different overlapping rates and conducting correlation analysis between parameters. Based on the artificial neural networks and genetic algorithms, the width and depth of the tempering zone are selected as target values for parameter optimization. The aim is to find the nonlinear relationship between the laser power, spot diameter, scanning speed, laser overlapping rate, and the size of the tempering zone, which can accurately predict the size of the tempering zone. The material microstructure of 40Cr gear steel was characterized by the scanning electron microscope, microhardness tester and friction and wear tester. The results show that the training error and testing error of the output parameters in genetic algorithm optimized back propagation network can accurately predict the size of the tempering zone. It is found that the higher the lap rate, the more uniform the hardness of the phase transformation hardening layer surface, and the tempering softening zone becomes larger. The parts surface is easy to produce defects, which can provide a theoretical basis for optimizing the laser quenching process parameters.

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Section: Introductionmentioning

confidence: 99%

Optimization of laser irradiation process parameters for 40Cr steel based on back propagation neural network and genetic algorithm

Chang

Deng

Sun

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part L:

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Influence of complex geometries on the properties of laser-hardened surfaces

Volpp

Dewi

Fischer

et al. 2020

Int J Adv Manuf Technol

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Laser surface hardening provides for many advantages in terms of flexible production due to very localized and controlled energy input into the material. Laser processing offers the possibility to treat surfaces in order to locally strengthen the areas that are prone to fatigue cracking. It is well known that laser energy absorption depends on many parameters, e.g., the surface structure and the surface orientation. The incident angle of the laser beam plays a key role in this regard. When complex geometries like crankshaft fillets are treated, the surface cannot be considered a series of flat surfaces. Obviously, this leads to locally varying degrees of energy absorption. In the present work, curved surface structures were chosen in order to analyze the impact of the geometrical characteristics on surface and subsurface material properties after laser treatment. Microstructure evolution generally was found to be similar for flat and curved geometries. However, even if higher absorption in the groove due to the illumination at larger incident angles was expected, the outer parts of the curved geometry were not fully hardened. Thus, the increased effective length of the complex geometry-treated and the larger heat-affected volume are expected to have a more dominant influence on the final appearance of the subsurface microstructure. Eventually, for austenitization of the complete illuminated surface volume, the energy density needs to be increased.

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Numerical simulation and correlation research of multi-track overlapping laser quenching process for 40Cr steel

Chang

Deng

Gao

et al. 2023

Journal of Laser Applications

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Laser quenching has a short process cycle and high production efficiency, and it plays an important role in automobile, ship, machinery manufacturing, and other fields. The surface hardness of 40Cr steel laser quenching parts is uneven by unreasonable set on the quenching overlap zone. This will affect the microstructure of the quenched layer, resulting in cracking, corrosion during service, and other hazards that ultimately reduce reliability. Numerical simulations provide an effective way to quantitatively reveal the transient evolution of the multi-field coupling between temperature field, stress field, and phase transition field in quenching, which directly determines the extent of the overlap zone and quenching properties. The quenched phase transition layer profile is predicted to effectively determine the extent of the secondary tempering softening zone and solve the bottleneck problem of uneven surface hardness in quenching. The innovation of this paper is to establish a multi-field coupled numerical model of the 40Cr steel multi-track laser quenching process. The transient quenching temperature, phase transition hardening, and stress distribution were numerically calculated, and the size of the tempering zone under different overlapping rates was evaluated, revealing the internal coupling mechanism and correlation between multi-fields during the laser quenching. The quenching temperature, microstructure, and hardness distribution of 40Cr steel were tested by an infrared thermometer, Axio Vert A1 Zeiss microscope, Thermo ScientificTM Apreo scanning electron microscope, and Q10M microhardness tester, which verified the effectiveness of numerical simulation. The research can provide an important theoretical basis for optimizing quenching process parameters in production.

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A pragmatic approach for assessment of laser-induced compressive residual stress profiles

Cited by 3 publications

References 28 publications

Optimization of laser irradiation process parameters for 40Cr steel based on back propagation neural network and genetic algorithm

Optimization of laser irradiation process parameters for 40Cr steel based on back propagation neural network and genetic algorithm

Influence of complex geometries on the properties of laser-hardened surfaces

Numerical simulation and correlation research of multi-track overlapping laser quenching process for 40Cr steel

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