Microstructure evolution and mechanical anisotropy of M50 steel ball bearing rings during multi-stage hot forging

Jiang, Hongwei; Song, Yanran; Wu, Yucheng; Shan, Debin; Zong, Yingying

doi:10.1016/j.cja.2020.05.038

Cited by 20 publications

(4 citation statements)

References 29 publications

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“…Current research on bearing steel focuses on improving their performance, encompassing studies on various failure modes, methods of enhancing performance 19,20 , and precise control of carbides [21][22][23][24] . Simultaneously, simulations at macroscopic [25][26][27] , mesoscopic 10,28 and microscopic scales [29][30][31][32][33] have been conducted to study the operation of bearings, leading to the development of analytical models for various macroscopic failure modes of bearings. These models, in conjunction with theories like Hertz contact mechanics, fracture mechanics, and continuum mechanics, explore the evolution mechanism of failures from inception to eventually leads bearing destruction.…”

Section: Introductionmentioning

confidence: 99%

Multi-scale analysis method for crack damage in 8Cr4Mo4V alloys

Cao,

Ma,

Gong

et al. 2024

Preprint

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8Cr4Mo4V, as an ideal choice for aeroengines bearing materials, involves multi-scale damage mechanisms of the fatigue crack failures. Herein, we propose a multi-scale analysis method to analyze the crack initiation and propagation damage mechanisms of 8Cr4Mo4V alloy. We find that different crystal orientations produce distinctly different damage mechanisms. The second phase doping also has different strengthening effects on the matrix following bypass and cut-through mechanisms. Meanwhile, the study of the polycrystalline model verified the micro-scale inverse Hall-Petch relation, where material strength decreases with grain refinement. Phase transitions caused by dislocations lead to stress concentration at specific grain boundaries, becoming the main inducer for the nucleation of initial voids. To address micro-to-macroscale-crossing issues, we constructed a large-scale mesoscopic molecular dynamics simulation and proposed an analytical formula to predict the relationship between average grain size and yield stress. Finally, we combine macroscopic experiments, crystallographic analyses, and atomic-scale characterization, verifying the combined action of dislocations and stacking faults leads to the failure of the material.

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Section: Introductionmentioning

confidence: 99%

Multi-scale analysis method for crack damage in 8Cr4Mo4V alloys

Cao,

Ma,

Gong

et al. 2024

Preprint

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“…However, M50 material has low hot working plasticity and is vulnerable to forging defects. Because of this performance, M50 subjected to plastic deformation can only be done in restricted hot working conditions [8]. The hot forging process of the bearing ring is a non-uniform deformation process, resulting in a non-uniform distribution of grain size.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Crack Condition in Forging Products of M50 Bearing Steel Based on Processing Map Theory

Park

Han

Kwon

et al. 2023

Metals

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The microstructure of forged products significantly impacts their properties, and defects or carbide distribution are not visible to the naked eye. Isothermal compression tests on M50 steel with a Gleeble 3500 tester were conducted to study microstructure behavior during forging. Tests examined the hot deformation behavior within a temperature range of 900–1200 °C and a strain rate range of 0.01–10 s−1. Power dissipation efficiency (η) and flow instability (ξ), which are crucial processing map parameters, were employed to analyze the high-temperature deformation behavior of M50 steel. The 3D processing map determined the optimum forging conditions, indicating that hot working should start at an initial temperature of 1050 °C or higher and a strain rate of 1 s−1, decreasing the strain rate and temperature as the strain increases. The 3D power dissipation efficiency map displayed an average value of 0.43 or higher at a strain rate of 0.1 s−1 and a temperature of 1150 °C before reaching a strain rate of 0.8. The Finite Element Method (FEM) simulated results, revealing ξ and η distributions, and confirmed that microstructure observation during deformation matched the hot forging parameters. This approach can effectively predict microstructure changes during hot forging.

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“…As a typical molybdenum high speed steel, 8Cr4Mo4V steel has excellent strength and thermal stability and is widely used in aircraft engine main bearings with service temperature below 315℃ [2]. Currently, some researchers have improved the wear resistance of 8Cr4Mo4V bearing materials and components while maintaining their basic mechanical properties by various methods such as deformation [3], heat treatment [4] and surface treatment [5]. However, the process described above can only be applied to manufacturing processes of bearings and may have a detrimental effect on surface quality and dimensional accuracy, making it difficult to exceed their performance limits.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of Electroshock Treatment on Hardness and Wear Resistance of Tempered 8Cr4Mo4V

Song,

Lu,

et al. 2023

Advances in Transdisciplinary Engineering

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In order to further improve the wear resistance of tempered 8Cr4Mo4V steel, an electroshock treatment (EST) was conducted on the material. By means of Vickers hardness and friction-wear tests, the influence of different EST parameters on the wear resistance of materials was analyzed. The result proves that a slight decrease in the Vickers hardness of the sample is caused by EST, but the hardness consistency significantly is improved (44.7%) under appropriate treatment parameter (EST2). Meanwhile, the wear rates of specimens decrease by 42.9%, 50.0% and 71.4% under treatment of EST1-EST3, respectively. The EBSD and XRD indicates that the changes in hardness and wear resistances of 8Cr4Mo4V originates from the comprehensive effect of dislocations and carbides under the regulation of EST. In EST1, the precipitation and aggregation of carbides promotes secondary hardening, thereby reducing the wear rate. Opposite phenomenon occurs in EST2, carbide precipitation is suppressed while the lattice distortion is aggravated, the hardness rebounds slightly compared to EST1. In EST3, the greater decrease in hardness results in the formation of oxide film on the surface, further reducing the friction coefficient and wear rate.

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Microstructure evolution and mechanical anisotropy of M50 steel ball bearing rings during multi-stage hot forging

Cited by 20 publications

References 29 publications

Multi-scale analysis method for crack damage in 8Cr4Mo4V alloys

Multi-scale analysis method for crack damage in 8Cr4Mo4V alloys

Numerical Simulation of Crack Condition in Forging Products of M50 Bearing Steel Based on Processing Map Theory

Mechanism of Electroshock Treatment on Hardness and Wear Resistance of Tempered 8Cr4Mo4V

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