Numerical Simulation of Vacuum Arc Remelting Process for Φ300 mm γ-TiAl Alloy Ingot
The vacuum arc remelting(VAR)process of 300 mm diameter γ-TiAl alloy ingot was studied by numerical simulation methods.The influence of the melting pool shape,temperature field,and stress field during VAR process of TiAl alloy under different conditions was obtained.The results showed that at the initial stage of VAR,the melting pool had a flattened shape,and it became deeper and V-shape during the stable melting stage.During the melting process,there were tensile stress zones on the surface of the solidified region of the ingot,and the tensile stress increased with the progress of melting,reaching a maximum of 430 MPa.During the subsequent cooling process,the tensile stress decreased,and at 400 s after the end of melting,the maximum tensile stress decreased to 180 MPa.The melting process was simulated separately at melting speeds of 3 kg/min,6 kg/min,9 kg/min,and 12 kg/min.As the melting speed increased,the melting pool became deeper,and the shape of the melting pool changed from V-shaped to U-shaped.At 500 s after the end of melting,the maximum tensile stress on the surface of the ingot prepared at a melting rate of 3 kg/min is 120 MPa,and the maximum tensile stress on the surface of the ingot prepared at a melting rate of 12 kg/min is 235 MPa.The heat transfer coefficient had a certain influence on the shape of the melting pool,with the increase of heat transfer coefficient,the shape of bottom of the molten pool changes from wide to shape,but it has little effect on the depth of the melting pool and a relatively small impact on the stress field in the ingot.
γ-TiAl alloyVacuum arc remelting(VAR)Melting pool shapeStress fieldTensile stress
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