隧道掘进机滚刀涂层的激光熔覆修复实验与仿真研究

Experimental and Simulation Research on the Laser Cladding Repair of Tunnel Boring Machine Cutters’Coating

隧道施工中,隧道掘进机(TBM)的滚刀磨损严重,对更换下来的滚刀直接做报废处理造成了资源浪费、施工成本增高。针对滚刀磨损的再制造修复策略这一问题,本文开展了激光熔覆仿真及新型涂层激光熔覆实验研究,对提高滚刀的磨损质量进行了相关的探索与实践.首先通过有限元仿真建立了双椭球体热源激光熔覆仿真模型,探究激光熔覆对滚刀基层及熔覆层材料残余应力的影响,并为熔覆实验提供了工艺参数优化的依据;在此基础上,利用相关实验条件,将激光熔覆技术与新型材料石墨烯相结合,开展了滚刀新型涂层的激光熔覆实验.利用正交试验的方法将石墨烯含量、激光功率、扫描速度和送粉盘转速作为试验因素,将表面硬度和耐磨性作为评价依据,分别设置4组不同水平进行比较,从而优选具有更高耐磨性的材料配比与工艺参数.结果表明,石墨烯的加入对涂层的耐磨性具有大幅的提高,与基体材料相比,加入石墨烯的涂层,其磨损程度较传统涂层最大可减少91.32%,较基体材料最大可减少99.86%.本文通过对激光熔覆技术和新型材料石墨烯的研究,采取仿真与实验相结合的手段,为提高TBM滚刀的磨损质量、选择其再制造策略提供了方法指导与数据支持.

Heavily worn cutters of a tunnel boring machine(TBM)are scrapped during tunnel construction,resulting in waste of resources and increased construction costs.To address the lack of remanufacturing and repair strategies for cutters,a laser cladding simulation and new coating lasers have been carried out.The cladding experiment research carried out relevant exploration and practice on the remanufacturing research of cutters.This paper established a double ellipsoid heat source laser cladding simulation model through finite element simulation.Moreover,the influence of laser cladding on the residual stress of the cutter base and cladding layer material was investigated.The basis of process parameter optimization for the cladding experiment was provided by finite element simulation.Combining the laser cladding technology with graphene,the laser cladding experiment of the new cutter was carried out.Using the orthogonal test method,the graphene content,laser power,scanning speed,and speed of the powder feeding plate were taken as test factors,while the surface hardness and wear resistance were taken as the evaluation basis.Four groups of different levels were set for comparison to select the material ratio and process parameters with higher wear resistance.The laser cladding experiment of the coating shows that the addition of graphene can greatly improve the wear resistance of the coating compared with the base material.Coating with graphene can reduce the wear quality by 91.32%when compared with traditional coating,which can be reduced by 99.86%when compared with the base material.In this paper,through the study of laser cladding technology and graphene,the combination of simulation and experiment provides method guidance and data support for improving the wear quality of the TBM cutter and selecting a remanufacturing strategy.