The potential for suppressing rail defect growth through tailoring rail thermo-mechanical properties
Thermal damage of rails can occur through brake lock-up, or traction control system failure to prevent wheel spin. In most cases the damage produced is shallow and takes the form of a “white etching layer”, usually thought to have a martensitic structure, formed as the steel is heated above its eute...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier Science Ltd
2016
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| Subjects: | |
| Online Access: | http://eprints.uthm.edu.my/3704/ http://eprints.uthm.edu.my/3704/1/AJ%202017%20%2894%29%20The%20potential%20for%20suppressing%20rail%20defect.pdf |
| Summary: | Thermal damage of rails can occur through brake lock-up, or traction control system failure to prevent wheel spin. In most cases the damage produced is shallow and takes the form of a “white etching layer”, usually thought to have a martensitic structure, formed as the steel is heated above its eutectoid tem-perature and then rapidly cooled as the wheel moves away. In many cases such layers are benign, but there is evidence of crack initiation at their interface with the sub-surface layers of the rail in “stud” defects. The metallurgical transformation during the formation of white etching layers leads to a volume change for the steel, leaving not only a transformed microstructure, but also locked-in stress. The influence of this additional locked-in stress on development of an initiated crack is studied in this paper, and the work extended to consider how alternative materials which react differently to the thermal input may offer a means to suppress crack development through locking in beneficial rather than problematic stresses. |
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