Corrosion fatigue lifetime assessment of high-speed railway axle EA4T steel with artificial scratch

0544864 - ÚFM 2022 RIV GB eng J - Journal Article
Hu, Y. - Wu, S. - Withers, P.J. - Cao, H. - Chen, P. - Zhang, Y. - Shen, Z. - Vojtek, Tomáš - Hutař, Pavel
Corrosion fatigue lifetime assessment of high-speed railway axle EA4T steel with artificial scratch.
Engineering Fracture Mechanics. Roč. 245, MAR (2021), č. článku 107588. ISSN 0013-7944. E-ISSN 1873-7315
Institutional support: RVO:68081723
Keywords : High cycle fatigue * Defect-tolerant design * Crack initiation and propagation * Stress corrosion cracking * High-speed railway axles
OECD category: Materials engineering
Impact factor: 4.898, year: 2021
Method of publishing: Open access
https://www.sciencedirect.com/science/article/pii/S001379442100059X?via%3Dihub

The effects of environment (in air and 3.5 wt% NaCl solution) and artificially-induced surface scratches are investigated on the fatigue properties of railway EA4T (also called 25CrMo4) alloy steel. This steel is found to be markedly sensitive to the chloride-containing environment, with cracking at stresses two thirds of the in-air fatigue limit (+/-326 MPa) under rotating bending (Wohler) tests. The scratched specimens show even shorter lifetime at stresses below 300 MPa and no fatigue limit is found down to 100 MPa. The fracture surfaces are characterized by the initiation of cracks from multiple sources and intergranular cracking. The fatigue failure of smooth specimens tends to initiate from localized corrosion pitting, while the corrosive environment facilitates crack initiation without pitting for scratched specimens. The fatigue crack growth rate in NaCl solution is slightly higher than that in air. Within the framework of defect-tolerant design, El-Haddad modified Kitagawa-Takahashi (KT) diagrams are constructed to explore the variation in fatigue strength and the defect assessment for both conditions. The modified KT model, which takes the short crack behavior into account, is in better agreement with the experimental results than the original KT diagrams.
Permanent Link: http://hdl.handle.net/11104/0321663