激光熔覆420不锈钢的热流耦合数值模拟与试验验证  

Numerical simulation and experimental verification on heat⁃flow coupling during laser cladding of 420 stainless steel

作　　者：杜茂华[1] 张振新 毕贵军 曹立超 Du Maohua;Zhang Zhenxin;Bi Guijun;Cao Lichao(Faculty of Mechanical and Electrical Engineering,Kunming University of Science and Technology,Kunming Yunnan 650504,China;Institute of Intelligent Manufacturing,GDAS,Guangzhou Guangdong 510070,China;Guangdong CAS DoFortune Laser Technology Co.,Ltd.,Foshan Guangdong 528000,China)

机构地区：[1]昆明理工大学机电工程学院,云南昆明650504 [2]广东省科学院智能制造研究所,广东广州510070 [3]广东中科德弗激光科技有限公司,广东佛山528000

出　　处：《金属热处理》2024年第8期211-219,共9页Heat Treatment of Metals

基　　金：佛山市科技创新团队项目(FS0AA-KJ919-4402-0101);广东省科学院发展专项资金(2022GDASZH-2022010107,2022GDASZH-2022010108)。

摘　　要：研究主要工艺参数(激光功率、扫描速度、送粉速率)对激光熔覆420不锈钢过程中熔池温度和单道熔覆层几何尺寸的影响,以及熔覆层不同位置处温度、温度梯度、流速的变化规律。建立了在Q235碳钢基板上激光熔覆420不锈钢粉末的热流耦合三维瞬态数值模型,模拟激光熔覆的成形过程;考虑了熔池内的浮力、Darcy阻力以及表面张力驱动的Marangoni效应,采用表观热容法考虑材料的相变潜热,任意拉格朗日欧拉法(ALE)用于追踪熔池的自由表面和模拟熔池的生长。结果表明,熔池温度随着激光功率和送粉速率的增加而增加,随着扫描速度的增加而减小。对熔覆层宽度影响最大的工艺参数是激光功率,激光功率从800 W增加到1000 W,熔覆层宽度增加了175.4051μm;对熔覆层高度和深度影响最大的均是送粉速率,送粉速率从1.49 g/min增加到3.17 g/min,熔覆层高度增加了309.8188μm,熔覆层深度减小了152.0495μm。不同的激光熔覆工艺参数下,从熔覆层顶部到底部硬度均不断减小。经试验验证,该模型能够准确预测不同工艺参数的激光熔覆过程。Influence of the main process parameters(laser power,scanning speed,powder feeding rate)on the molten pool temperature and the geometry of single track clad layer during laser cladding on 420 stainless steel,as well as the variation of temperature,temperature gradient and flow rate at different positions of the clad layer were studied.A heat⁃flow coupled 3D transient numerical model for laser cladding of 420 stainless steel powder on Q235 carbon steel substrate was established to simulate the forming process of laser cladding.The buoyancy force,Darcy resistance and Marangoni effect driven by surface tension in the molten pool were considered.The apparent heat capacity method was used to consider the latent heat of the material phase transition.The arbitrary Lagrangian⁃Eulerian(ALE)method was used to trace the free surface of the molten pool and simulate the growth of the molten pool.The results show that the molten pool temperature increases with the increase of laser power and powder feeding rate,but decreases with the increase of scanning speed.The process parameter that has the greatest influence on the clad layer width is the laser power and when it increases from 800 W to 1000 W,the cladding width increases by 175.4051μm.The powder feeding rate has the greatest influence on the height and depth of clad layer.The powder feeding rate increases from 1.49 g/min to 3.17 g/min,the clad layer height increases by 309.8188μm,while the clad layer depth decreases by 152.0495μm.Under different laser cladding process parameters,the hardness from the top to the bottom of the clad layer decreases continuously.The experimental results show that the model can accurately predict the laser cladding process with different process parameters.

关 键 词：激光熔覆 420不锈钢粉末 热流耦合 MARANGONI效应 硬度 

分 类 号：TG456.7[金属学及工艺—焊接]