高速激光熔覆平板和外/内轴熔池动态演化研究  

Dynamics of Molten Pool Evolution on Flat Plates and Outer/Inner Shaft Surfaces in High-Speed Laser Cladding

作　　者：付延昭 顾衡 钱黎黎 任旭东[1] Fu Yanzhao;Gu Heng;Qian Lili;Ren Xudong(School of Mechanical Engineering,Jiangsu University,Zhenjiang 212013,Jiangsu,China;School of Energy and Power Engineering,Jiangsu University,Zhenjiang 212013,Jiangsu,China)

机构地区：[1]江苏大学机械工程学院,江苏镇江212013 [2]江苏大学能源与动力工程学院,江苏镇江212013

出　　处：《激光与光电子学进展》2024年第23期294-308,共15页Laser & Optoelectronics Progress

基　　金：国家自然科学基金(52205370);江苏省自然科学基金(BK20210757);江苏大学科研启动金(20JDG057)。

摘　　要：采用计算流体动力学仿真模型分别在平板、外轴和内轴上进行高速激光熔覆,探究扫描工艺参数对熔覆层形貌和熔池的影响,同时分析在不同工件上进行单道和多道扫描时熔池动态演化过程的差异。结果表明:随着扫描速度的增加,熔池逐渐减小。在相同的工艺参数下,平板上的熔池最大,并且熔覆层的宽度和高度随着扫描速度的增加而逐渐减小。在工艺参数相同时,平板上的熔覆层宽度最小,高度最大,外轴上的熔覆层宽度和高度均小于内轴。在进行多道熔覆的过程中,随着扫描道数的增加,熔池也随之增大。值得注意的是,从第二道开始,每一道扫描都导致熔覆层宽度的增加大于设定的搭接偏移量,并且随着扫描道数的增加,每一道扫描后熔覆层增加的宽度也逐渐增大。在外轴和内轴上,由于重力的作用效果,熔池产生了不同的动态流动,而在平板上,重力对熔池流动的影响较小。在平板、外轴和内轴上熔覆层中心纵向截面的熔池动态演化过程中,熔池的流动方式相同,熔池内的液体在马兰戈尼力和表面张力的共同作用下朝着熔池的末端流动。熔池的最大流速分别是0.931 m/s、0.964 m/s和1.385 m/s,其中平板上的熔池流速最小,内轴上的熔池流速最大。温度梯度随熔覆速度的增大而减小,当熔覆速度相同时,平板上的温度梯度最大,内轴上的温度梯度最小。This study utilizes a computational fluid dynamics(CFD)model to conduct high-speed laser cladding on flat plates,outer shafts,and inner shafts.The research aims to investigate the influence of process parameters on the clad morphology and molten pool.The differences in the dynamic evolution of molten pools during single and multi-pass cladding on different workpieces are analyzed.The results indicate that as the cladding speed increases,the molten pool gradually decreases in size.With the same process parameters applied,the molten pool on the flat plate is the largest,and the width and height of the clad layer decrease with the increase in cladding speed.With identical process parameters,the clad layer on the flat plate has the smallest width and the highest height;meanwhile,the clad layer width and height on the outer shaft are both smaller than those on the inner shaft.During the multi-pass cladding process,the molten pool increases in size with the addition of cladding passes.It is noteworthy that starting from the second pass,each scanned pass leads to an increase in the clad layer width greater than the set hatch spacing,and this increase further grows with the increase in the number of scanning passes.On the outer and inner shafts,the molten pool exhibits flow in different flow dynamics due to the effect of gravity,while on the flat plate,gravity has a relatively minor impact on molten pool flow.In the longitudinal section of the clad layer center on flat plates,outer shafts,and inner shafts,the dynamic evolution of molten pools follows a similar flow pattern.The liquid inside the molten pool flows towards the end of the pool under the combined effects of Marangoni force and surface tension.The maximum flow velocities of the molten pool are 0.931 m/s,0.964 m/s,and 1.385 m/s,with the lowest flow velocity observed on the flat plate and the highest on the inner shaft.The temperature gradient decreases as the cladding speed increases.Under equivalent cladding speeds,the highest temperature gradient is observed

关 键 词：高速激光熔覆 计算流体动力学 轴类零件 多道扫描 熔池演化 重力影响 

分 类 号：TN249[电子电信—物理电子学] TG665[金属学及工艺—金属切削加工及机床]