Numerical study of aluminum segregation during electron beam cold hearth melting for large-scale Ti-6％Al-4％V alloy slab ingots
A three-dimensional multi-physics coupled numerical model was established and validated to study the control mechanism of aluminum segregation in large TC4(Ti-6％Al-4％V)titanium alloy slabs during electron beam cold hearth melting(EBCHM).It qualitatively predicts the macroscopic segregation trends of aluminum under different casting conditions in the melting and solidification zones.The results indicate that the increase in casting speed has little effect on controlling aluminum segregation due to the longitudinal evolution trend of the melt pool shape near the overflow port.Lowering the liquid surface temperature is an effective solution to limit aluminum evaporation loss and control aluminum segregation.For the EBCHM process with a casting speed of 8 mm/min,as the liquid surface temperature decreases from 2 273 K to 2 073 K,the segregation degree of aluminum in the melt pool,φ1,increases from 0.78 to 0.96,and the corresponding segregation degree of aluminum on the solidification cross-section,φc,increases from 0.67 to 0.93.
electron beam cold hearth meltingTi-6％Al-4％V slabaluminum evaporationmacroscopic segregation
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