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Abstract Abstract：With the increasing of high-speed railway mileage, the wheel webs are subjected to long-term exposure to humid and even marine atmospheres, making corrosion pits be one of the main causes of wheel failure. To more closely match the actual working conditions, in this paper, high-cycle fatigue specimens of ER8C wheel steel are firstly subjected to a 180-day pre-corrosion test under atmospheric conditions. That is different from the artificial accelerated corrosion condition employed in many other studies. Then, the surface morphologies, sizes, and distribution of corrosion pits are characterized by scanning electron microscope (SEM), followed by the high-cycle fatigue tests. The results show that the fatigue limit of pre-corrosion steel is 387 MPa, which is 12% lower than that of the uncorroded steel. This is mainly due to the local stress concentration caused by the corrosion pits on the specimen surface, which accelerates the fatigue crack initiation. And then, laser confocal microscopy is used to measure the pit sizes at the specimen surface and the mean pit size, including depth, width and shape ratio, are obtained. Finally, the equivalent initial flaw size (EIFS), calculated from the mean pit depth and width, is used to predict the remaining life of the wheel steel. This method avoids the difficulties of fatigue crack initiation and short crack growth modeling on the prediction of fatigue life. The calculated remaining life of the wheel steel is more in line with the experimental results and proves the feasibility of the method. In this paper, the main conclusion is that the EIFS can be obtained by counting the mean pit depth and width of the specimen surface pit size . And the method of EIFS allows the calculation of the remaining life of wheel steel after atmospheric pre-corrosion. This verifies the applicability of the EIFS method in fatigue life of materials under atmospheric pre-corrosion.
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Received: 20 September 2022
Published: 19 June 2023
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Corresponding Authors:
Ao Ni无
E-mail: aoni@swjtu.edu.cn
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2023, Vol. 44 
