| ZHU Shou-dong,ZHANG Ji-wang,LU Qi,ZHANG Hao-nan.Research on the Fatigue Strengthening Influencing Factors of Micro Shot Peened High Speed Railway Axle Steel[J],50(12):140-148, 166 |
| Research on the Fatigue Strengthening Influencing Factors of Micro Shot Peened High Speed Railway Axle Steel |
| Received:April 20, 2021 Revised:May 26, 2021 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2021.12.014 |
| KeyWord:shot peening EA4T residual stress roughness microstructure strengthening |
| Author | Institution |
| ZHU Shou-dong |
State-Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu , China |
| ZHANG Ji-wang |
State-Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu , China |
| LU Qi |
State-Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu , China |
| ZHANG Hao-nan |
State-Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu , China |
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| Abstract: |
| In this study, the effects of the residual stress, the microstructure strengthening layer and the surface roughness on the fatigue performance of micro shot peened EA4T axle steel were evaluated. Two tempering treatments of 250 ℃ for 2 h and 550 ℃ for 4 h were applied on the micro shot peened specimens, and the fatigue effects of the residual stress and the microstructure strengthening layer of shot peened specimens were carefully studied. The surface roughness, 3D morphology, residual stress distribution, X-ray diffraction peaks, full width at half maximum of X-ray diffraction profiles and surface hardness of the peened and tempered specimens were tested and analyzed, and the rotating bending fatigue test was performed to determine the fatigue performance. The results showed that the micro shot peening treatment increased the surface roughness, and introduced the compressive residual stress and work hardening with the depth of about 80~100 μm on the surface. Micro shot peening process improved the fatigue limit of the material from 365 MPa to 470 MPa. The surface microstructure of the tempered specimens recovered, the micro hardness decreased, and the residual stress released. And the tempering treatments of 250 ℃ for 2 h and 550 ℃ for 4 h reduced the fatigue limit of shot peened specimens to 450 MPa and 430 MPa, respectively. According to the test results, the fatigue strength influencing factors of micro shot peened EA4T axle steel are quantitatively evaluated, and the results show that the residual stress and the surface microstructure strengthening layer increase the fatigue strength by about 16% and 23.8% respectively, while the surface roughness reduces the fatigue strength by about 10%. |
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