Effect of laser cladding Fe-based alloy on wear performance of wheel and rail steels

Laser clad Fe-based alloy coatings were prepared on surface of wheel and rail materials by a CO2 multimode laser.Microstructure and micro-hardness of the coatings were analyzed. The rolling wear properties of the untreated and laser clad specimens were investigated on a MMS-2A testing apparatus. The results show that the microstructure of Fe-based alloy coatings is composed of dendrite structure and eutectic structure. Affected by the solidification conditions,the coarse crystal structure is observed in the binding region while the cellular dendrite and dendrite structure forms in the middle and the surface regions of the coatings.( Fe,Ni) solid solution and high-hardness chromium carbide are defected. The hardness of laser clad wheal and rail specimens is increased by 122. 6%and 141. 6% compared with the untreated specimens,respectively. The wear rates of untreated wheel and rail specimens are higher and the wear mechanism is dominated by fatigue wear with obvious plastic deformation and fatigue cracks. The lower wear rates of the laser clad wheel and rail specimens are observed and the main wear mechanism is fatigue wear.