TD3真空自耗熔炼过程数值模拟及裂纹预测

Numerical Simulation and Crack Prediction of TD3 Alloy during Vacuum ArcRemelting

利用ProCAST软件对TD3合金真空自耗熔炼过程进行数值模拟,研究了不同条件下熔池形状、温度场和应力场的分布规律,分析了熔速、传热系数和熔炼温度等对铸锭最大等效应力的影响,对裂纹进行预测和试验验证。结果表明,随熔炼进行,熔池形状由扁平状逐渐转变为漏斗状;TD3整锭温度下降至773 K以下时,铸锭圆周表面距底部78 mm处,等效应力最大,达到614 MPa,铸锭外表面处于压缩状态,中心处于拉伸状态,内外应力差较大,易形成裂纹;降低熔速至4 kg/min以下,降低冷却速度使传热系数≤2 000 W/(m^(2)·K),可以减小气隙宽度,从而改善铸锭产生裂纹缺陷情况。

The vacuum arc melting process of TD3 alloy was simulated by the ProCAST software to investigate the distribution law of molten pool shape,temperature field and stress field under different conditions.The influence of pro⁃cess parameters such as melting rate,heat transfer coefficient and melting temperature on the maximum effective stress of ingot was analyzed,and cracks were predicted and verified.The results indicate that the shape of molten pool is gradually deepened from flat shape to funnel shape with the melting proceeding.When the temperature of whole TD3 ingot is decreased below 773 K,the effective stress of ingot circumference surface reaches up to 614 MPa at 78 mm from the bottom.The outer surface of the ingot is in a state of compression,while the center is in a state of tension,and the great difference between internal and external stress leads to cracks.Through reducing melting rate less than 4 kg/min or reducing cooling rate to make the heat transfer coefficient≤2000 W/(m^(2)·K),it can shorten the air gap width,thereby improving the crack defects.