Enhancement of Fatigue Endurance Limit through Ultrasonic Surface Rolling Processing in EA4T Axle Steel
Autor: | Liqin Chen, Xiaodi Wang, Peng Liu, Xuechong Ren, Guobiao Lin |
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Rok vydání: | 2020 |
Předmět: |
lcsh:TN1-997
Materials science microstructure residual stress 02 engineering and technology ultrasonic surface rolling processing 01 natural sciences Indentation hardness Residual stress fatigue endurance limit 0103 physical sciences Surface roughness General Materials Science Composite material lcsh:Mining engineering. Metallurgy 010302 applied physics Metals and Alloys 021001 nanoscience & nanotechnology Microstructure Fatigue limit Axle Transmission electron microscopy microhardness axle steel Ultrasonic sensor 0210 nano-technology |
Zdroj: | Metals, Vol 10, Iss 830, p 830 (2020) Metals Volume 10 Issue 6 |
ISSN: | 2075-4701 |
DOI: | 10.3390/met10060830 |
Popis: | Fatigue property is a key evaluation index for the service reliability of railway axle. In this work, the effect of ultrasonic surface rolling processing (USRP) on the surface characteristic and fatigue property was investigated in an EA4T axle steel used on high speed trains by several characterization techniques and the staircase method fatigue testing. The surface characteristics were initially studied in EA4T axle steel under different static loads of 1.0 kN, 1.5 kN and 2.0 kN, and served as the important USRP parameter. It was found that the larger static load greatly improved the surface microstructure, microhardness and compressive residual stress, but also increased the surface roughness. Furthermore, the rotating bending fatigue endurance limit of the USRP specimen with a static load of 1.5 kN was obviously enhanced by ~14% (from ~352 MPa to ~401 MPa) relative to the untreated specimen. The enhanced fatigue limit induced by USRP was attributed to the synergistic effect of the grain refinement, as evidenced by transmission electron microscope (TEM) observation, work-hardening, the increased compressive residual stress and the reduced surface roughness. Moreover, the fatigue limit of the USRP specimen was ~4% higher than that of the rolling specimen with turning off the ultrasonic system, ~386 MPa, which showed that the role of the ultrasonic impact could enhance the fatigue property. These findings demonstrate the validity of this technique in modifying the surface characteristics and thus improving the fatigue resistance of axle material, further ensuring its service safety and reliability. |
Databáze: | OpenAIRE |
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