35CrMnSi表面激光熔覆残余应力场数值分析

Numerical Analysis of Residual Stress Field of Laser Cladding on 35CrMnSi Surface

为选择合适的熔覆工艺参数,降低修复后零件的残余应力,利用ANSYS软件对熔覆件进行瞬态热分析,将得到的节点温度转换为温度载荷进行热力耦合计算,并采用“生死单元”技术模拟熔覆层,分析了沿熔覆层深度方向上残余应力的分布规律。结果表明,X方向残余应力大于其他2个方向的应力,在熔覆层和熔合区均表现为拉应力,拉应力最大值出现在距熔覆层顶部1.7 mm处;Y方向残余应力在熔覆层和熔合区都为拉应力,在基材热影响区由拉应力逐渐变为压应力;Z方向残余应力在熔覆层内表现为轻微的拉应力,在基体内逐渐变为压应力。熔覆层残余拉应力随激光功率增加而增大,随扫描速度增加而减小,相较于扫描速度,激光功率的变动对残余应力的影响更大。研究表明,在模拟工况下,最优工艺参数组合为P=500 W,v=8 mm/s。

In order to select appropriate cladding process parameters and reduce the residual stressof repaired parts,the transientnodetemperature obtained from thermal analysis was converted into temperature load by ANSYS software for thermo-mechanical calculation,and the formation of cladding layer was simulated by the"Birth and Death element"technology,and thedistribution law of residual stress along the depth direction of cladding layer was analyzed.The results show that the residual stress in the X direction is larger than the stress in the other two directions,and it is tensile stress in cladding layer and the fusion zone,the maximum stress appears 1.7 mm from the top of the coating;the residual stress in Y direction is tensile stress in both the cladding layer and the fusion zone and gradually changes to compressive stress in the heat affected zone;Z-directional stress is tensile stress in the cladding layer and gradually changes to compressive stress in the substrate.The residual tensile stress of cladding layer increases with the increase of laser power and decreases with the increase of scanning speed.The change of laser power has a greater effect on the residual stress than the scanning speed.The study show that the optimal process parameter combination is P=500 W,v=8 mm/s undersimulated conditions.