无缝线路磨损钢轨激光熔覆自动修复方式的研究

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

由于列车的高速化和重载化,钢轨磨损问题越来越严重,采用修复质量高、修复速度快的激光熔覆技术可以对其进行在线快速修复。为此,采用三维扫描仪首先对磨损钢轨进行扫描,然后将扫描点云数据进行三维重构、路径规划及数据格式转换,最后利用优化的数据驱动机器手臂和激光熔覆装置对磨损钢轨进行自动修复。修复工艺结果表明,对5 mm的磨耗层进行7层修复,利用修复道与道之间和层与层之间的回火作用,修复层的组织马氏体含量少,硬度为330~360 HV;经过600℃回火处理10 min后,加入钒元素的铁基合金粉末激光熔覆修复后钢轨母材、热影响区、修复层硬度均在300~340 HV,组织为回火索氏体;修复钢轨的耐磨性约为钢轨母材的87%,达到修复目的。

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 3 D scanner is used to scan the worn rail firstly, and the scanning point cloud data is used for 3 D 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 5 mm 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.