Study on Realization Method of Automatic Repair Wear Rail by Laser Cladding

Abstract

The rail abrasion is getting more and more serious due to the high speed and heavy load of the train. Laser cladding technology can repair worn rails online with high quality and high speed. For this reason, a 3D scanner is used to scan the worn rail firstly, and the scanning point cloud data is used for 3D reconstruction to form a solid model. Then the repair path planning and data format are transferred to adapt the robot arm. Finally the optimized data which could drive the machine arm and laser cladding device to repair the worn rail is obtained. The results show that: the 5mm high wear of the rail is repaired by 7 layers, and the microstructure of the repaired layers has little martensite due to the tempering between scanning path by path, layer by layer. The hardness of the alloy is 330-360 HV. After a tempering treatment at 600℃ for 10 min, the microstructure of the Fe based alloy powder for the addition of vanadium after cladding is tempered sorbite, and the hardness of rail parent metal, heat affected zone and repaired layers of the alloy are both between 280 HV to 340 HV. The wear resistance of the repair zone is superior to the rail material, and the abrasion loss of the repair rail is 87% of the rail body, which indicated the rail repair purpose is achieved.