镍基高温合金真空自耗数值模拟

摘要：基于某特钢厂生产过程，对镍基高温合金的真空自耗过程进行数值模拟，研究了不同电流强度、熔速和通入氦气对铸锭Nb元素宏观偏析、黑斑形成的影响规律。铸锭在顶部和1/4处产生较为严重的宏观偏析。随着熔炼电流强度增加，铸锭顶部的磁场增加，顶部宏观偏析和1/4处黑斑逐渐加重。随着熔速的增加，熔池深度增加，铸锭顶部的Nb元素偏析加重，铸锭1/4处黑斑增加。熔炼时通入氦气，铸锭冷却速率大幅度提高，铸锭的元素偏析程度和黑斑明显减少，且最大偏析部位向铸锭顶部移动。

Numerical simulation of vacuum arc remelting nickel based superalloy

Abstract：Based on the process in a special steel plant, the vacuum arc remelting process of nickel based superalloys was simulated to investigate the effect of current intensity, melting rate, and helium gas cooling on macrosegregation of Nb and formation of freckles. The ingot has severe macrosegregation in the upper and 1/4 part of the ingot. With the current intensity increasing, the magnetic field in the upper part of the ingot increases, and macrosegregation and freckles increase gradually both in the upper and 1/4 part of the ingot. With the melting rate increasing, the depth of the molten pool increases, the macrosegregation of Nb increases in the upper part of the ingot, and the freckles increase significantly in the 1/4 part of the ingot. When helium is introduced into the ingot during smelting, the cooling rate increases greatly, the macrosegregation and freckles reduce significantly in the ingot, and the maximum segregation position moves to the top of the ingot.