不同扫描策略下316L/AISI304激光熔覆过程中温度场-应力场的数值模拟  

Numerical Simulation of Temperature Field and Stress Field in 316L/AISI304 Laser Cladding with Different Scanning Strategies

作　　者：吴俣 马朋召 白文倩 陈静青 Wu Yu;Ma Pengzhao;Bai Wenqian;Chen Jingqing(Key Laboratory of Advanced Technologies of Materials,Ministry of Education,School of Materials Science and Engineering,Southwest Jiaotong University,Chengdu Sichuan610031 China)

机构地区：[1]西南交通大学材料科学与工程学院,材料先进技术教育部重点实验室,四川成都610031

出　　处：《中国激光》2021年第22期12-23,共12页Chinese Journal of Lasers

基　　金：国家自然科学基金(51504198,51474178);中央高校基本科研业务费专项资金项目(A0920502051820-48)。

摘　　要：以316L不锈钢粉末为原料,采用激光熔覆技术以单向扫描和往复扫描两种方式在AISI304不锈钢表面进行多层多道熔覆,研究了熔覆层的组织以及熔覆层中的残余应力,并进行了有限元模拟。基于316L不锈钢粉末的激光熔覆层截面形貌,利用ABAQUS有限元软件建立复合热源模型,分别计算熔覆层的温度场及应力场。对熔覆层中的残余应力σ_(x)和σ_(y)进行测试,测试结果与模拟计算结果吻合得较好,验证了有限元模型的可靠性。温度场模拟结果表明,往复扫描路径下的热累积大于单向扫描路径下的热累积。结合温度场结果与微观组织分析了单向扫描路径下熔合线处的晶粒尺寸相比往复扫描路径下更均匀的机理。基于温度场结果分析了熔覆层中的应力分布规律以及往复扫描路径下的熔覆层应力大于单向扫描路径下的机理。Objective During the laser cladding process,the heat input of the laser heat source is not uniform,which will cause an uneven temperature field.The residual stress produced by the uneven temperature field will increase the crack tendency and affect the size,structure,and performance of the cladding layer,thereby considerably reducing the quality of the specimen.The cladding scanning method will affect the heat conduction and accumulation,thus affecting the stress and deformation of the work piece.Furthermore,the heat accumulation of the laser heat source considerably influences the morphology of the solidified structure of the cladding layer.An improved scanning method can produce a small heat-affected zone,stress,deformation and a fine and more uniform microstructure when using the same process parameters of laser cladding,thereby improving the manufacturability of laser cladding.The internal temperature change of the molten pool is difficult to measure using the existing test methods.Using numerical simulations to study the temperature and stress fields in the laser cladding process can greatly reduce the experimental cost and time.The temperature and stress field simulation results can be used to explain the influence of different scanning strategies on the characteristics of the cladding solidification structure and the distribution of residual stress.Methods AISI304 stainless steel and 316 L stainless steel powder are used in this study.The 316 L stainless steel coating is fabricated on the surface of AISI304 stainless steel via coaxial powder feeding laser cladding using codirectional and reciprocating scanning methods.Then,the cladding layer is sampled for metallographic analysis.The metallographic corrosion solution is the Fe Cl3 hydrochloric acid ethanol solution.Furthermore,the temperature and stress fields in the laser cladding process under different scanning strategies are calculated using the finite element simulation software ABAQUS.The influence of scanning strategies on the temperature and stress

关 键 词：激光技术 激光熔覆 有限元仿真 316L不锈钢 温度场 应力场 

分 类 号：TG174.44[金属学及工艺—金属表面处理] TG111.3[金属学及工艺—金属学]