1. 南昌大学 机电工程学院, 南昌 330031; 2. 九江学院 机械与材料工程学院, 九江 332005
发布日期:2020-01-06通讯作者:张华，男，教授，博士生导师，电话（Tel.）：13607005718；E-mail：hzhang@ncu.edu.cn.作者简介:张义福(1984-)，男，江西省上饶市人，博士生，讲师.主要从事异质金属焊接中多相IMCS调控与激光沉积制造研究.基金资助:国家自然科学基金委员会-中国科学院天文联合基金 (U1731118)，江西省轻质高强结构材料重点实验室开放基金（20171BCD40003）资助项目Effect of Deposition Path on Residual Stresses of Laser Additive Manufacturing Structures
ZHANG Yifu 1, 2,ZHANG Hua 1,ZHU Zhengqiang 1,SU Zhanzhan 1, 21. School of Mechanical and Electrical Engineering, Nanchang University, Nanchang 330031, China;2. School of Mechanics and Materials Engineering, Jiujiang University, Jiujiang 332005, China
Published:2020-01-06摘要/Abstract
摘要： 以H13工具钢粉末为原材料，使用激光金属沉积技术快速成形薄壁结构件.采用Fluent开发气体/金属粉末流计算流体动力学(CFD)模型，分析强制对流热损失参数.建立沉积过程热流本构方程，采用生死单元技术模拟金属沉积，基于APDL语言进行编译加载，实现激光金属沉积3D热-力顺序耦合有限元模拟.分析沉积路径对薄壁结构热分布和残余应力场分布不同模式的影响.结果表明：直壁结构拐角局部存在超过工件拉伸强度的残余拉应力，从而导致裂纹生成；与单向沉积路径不同，之字形沉积路径在沉积层中诱导不同符号的残余切应力；单向沉积壁温度梯度相对较低，其残余应力略低于之字形沉积壁，但成形结构件的整体质量较低；残余应力计算结果与实验测量值相吻合，可为特定零件几何形状沉积提供参考.
关键词: H13工具钢； 激光金属沉积； 热流本构方程； 3D热-力顺序耦合有限元； 残余应力场
Abstract: H13 tool steel powder is used as a raw material to rapidly form thin-walled structures using laser metal deposition technology. The gas/metal powder flow computational fluid dynamics (CFD) model was developed using Fluent software to analyze the forced convection heat loss parameters. The heat flow constitutive equations of the deposition process are established, the metal deposition is simulated using the life-and-death element technology, and the 3D thermo-mechanical sequential coupled finite element simulation of the laser metal deposition is performed based on the APDL language. The effects of deposition paths on the thermal distribution and residual stress field distribution of thin-walled structures were analyzed. The results show that there is a local residual tensile stress exceeding the tensile strength of the workpiece in the corners of the straight wall structure, resulting in cracks. Unlike the one-way deposition path, the zig-zag deposition path induces different symbolic residual shear stresses in the subsequent deposition layer. The temperature gradient of the one-way deposition wall is relatively low, and the residual stress is slightly lower than the zig-zag deposition wall, but the quality of the formed structures is low. The residual stress calculation results are in agreement with the experimental measurements, and can provide operation references for the deposition of specific part geometry.
Key words: H13 tool steel; laser metal deposition; heat flow constitutive equations; 3D thermo-mechanical sequential coupling finite element; residual stress field
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