Product Code: ICA13_1605

Study on the Friction and Wear Behavior of Laser Surface Strengthened Railway Steel
Authors:
Yinlan Zheng, Huazhong University of Science and Technology; Wuhan Peoples Republic of China
Qianwu Hu, Huazhong University of Science and Technology; Wuhan Peoples Republic of China
Xiaoyan Zeng, Huazhong University of Science and Technology; Wuhan Peoples Republic of China
Presented at ICALEO 2013

It is known that the rail-wheel mechanical system serving in rolling contact conditions can get damaged such as friction and wear, contact fatigue and so on. In this report, laser surface hardening of a wheel-shaped high carbon manganese rail steel (U71Mn) was studied under laboratory experiments on a friction and wear tester. The tester has simulated rolling speed, the experiment cycles, the axial loads of the friction discs, and the contact spot size were calculated based on the theory of Hertz elastic contact. Hardened depth and abrasion loss including weight and diameter in multi-parameters were detected. Microstructure, plastic deformation layer characters, fatigue cracking growth and extension path were analyzed. The experimental results indicated that micro-hardness was raised from 300HV to approximately 800HV due to the martensitic zone on the surface produced by laser surface strengthening. The wear resistance was enhanced by laser surface hardening, and the grinding depth decreased with the increasing of the hardening depth. Untreated specimen got the maximum abrasion. Under the same experiment cycles, less abrasion occurred in larger Rockwell hardness values. It is also found that there is a competition relationship between the wear resistance and the fatigue-cracking resistance for rail steels, and the wear resistance and the fatigue-cracking resistance should be optimally matched.