Numerical Simulation and Crack Prediction of TD3 Alloy during Vacuum Arc Remelting
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/(m2·K),it can shorten the air gap width,thereby improving the crack defects.
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