Laser strengthening of U71Mn rail steel was performed under different parameters using a narrow line-shaped CO₂ laser beam formed by newly developed binary optics. The microstructure, microhardness and wear resistance of the strengthened layers were investigated. Laser strengthening of PD₃ rail steel was performed using a normal circle-shaped beam, and the contact fatigue resistance of samples obtained by optimized laser processing parameters was investigated. The research results showed that a layer with fine martensite was produced on the surface of the rail steels after laser strengthening. The wear resistance to sliding friction was improved over 1.3-2.5 times than that of original steel U71Mn. And the rolling contact fatigue property was improved over 4-5 times than that of steel PD₃. The results also indicated that the laser strengthening processing parameters should be selected not to melt and overheat the surface.

Date Published: 13 January 2005
PDF: 7 pages
Proc. SPIE 5629, Lasers in Material Processing and Manufacturing II, (13 January 2005); doi: 10.1117/12.577026

Published in SPIE Proceedings Vol. 5629:
Lasers in Material Processing and Manufacturing II
ShuShen Deng; Akira Matsunawa; Y. Lawrence Yao; Minlin Zhong, Editor(s)