激光熔覆过程残余应力的数值模拟

Numerical Simulation of Residual Stress during Laser Cladding

在考虑热传导系数、比热容、热膨胀系数和弹性模量等热物性参数随温度变化的条件下,采用MSC.Marc软件对同步送粉激光熔覆2Cr13粉末的温度场、应力场进行了直接耦合分析,并进一步模拟得到了不同扫描速度下的应力场分布情况。考察工件表面和深度方向两条路径上的应力分布。结果表明,平行于激光扫描方向拉应力值远大于垂直激光扫描方向的拉应力值。由此推测,激光扫描方向上拉应力的存在是造成熔覆层裂纹的主要原因。随着扫描速度的增大,熔覆层表面的VonMises等效应力峰值也随之增大,曲线变得更陡。

Considering the thermal physical properties such as heat transfer coefficient,heat capacity,thermal expansion coefficient,and elastic modulus change with temperature,the temperature field and stress field of the synchronous powder feeding laser cladding process are conducted with direct coupled analysis using the software MSC.Marc.The residual stress distributions under different scanning speeds are studied.The stress distribution along the two paths with one on the surface of the workpiece and the other along the depth of the workpiece is measured,and the results show that the longitudinal stress is much greater than the value of transversal stress.It can be speculated that,along the laser scanning direction,the existence of the residual tensile stress caused by laser cladding is the main reason for cladding layer cracks.When scanning speed increases,the VonMises equivalent peak stress on the surface of the cladding layer also increases,and the curve becomes steeper.