水冷条件下WAAM温度场的数值模拟研究

Numerical Simulation of WAAM Temperature Field Under Water Cooling

针对熔化极丝材电弧增材制造(Wire arc additive manufacturing,WAAM)过程基板散热条件差导致热积累严重的问题,采用基板背面加水冷铜板的散热方式改善增材过程的散热,利用Abaqus软件分别模拟了有无水冷两种条件下增材时温度场的变化规律,并对模拟过程进行实验验证。结果显示,实验条件下基板测量点热循环曲线与模拟结果基本一致。有无水冷两种条件下基板温度均在第七层时达到最大;基板上高温区域扩展面积最大,基板在水冷条件下的冷却速率远大于无水冷条件下的冷却速率,且“双峰”效应较为明显。堆积第一层至第七层时,有无水冷两种条件下各层平均温度梯度逐渐减小,但前者始终大于后者,熔池体积不断变大。第七层至第十层时,成型件热积累接近饱和状态,此阶段成型件最易发生严重塌陷。

In order to solve the problem of serious heat accumulation caused by the poor heat dissipation condition of the substrate during the process of gas metal wire arc additive manufacturing(WAAM),the heat dissipation method of the substrate with water⁃cooling copper plate was used to improve the heat dissipation condition of the additive process.The temperature field change of additive manufacturing under the conditions of water cooling and without water cooling are simulated respectively using Abaqus software,and the simulation process is verified experimentally.The results show that the thermal cycle curve of the measurement point of the substrate under the experimental conditions is basically consistent with the simulation result.In both conditions with and without water cooling,the substrate temperature reached the maximum at the seventh layer,and the expanding of the high temperature area on the substrate was the largest.The cooling speed of the substrate under water cooling was much faster than that without water cooling,and the“double peak”effect was more obvious.When the first layer to the seventh layer are stacked,the average temperature gradient distribution of each layer with or without water cooling gradually decreases,but the former is always greater than the latter,and the volume of the molten pool continues to increase.During the seventh to tenth layers,the heat accumulation of the formed part is close to saturation,and it is most prone to severe collapse at this stage.