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钢锭中形成沟槽偏析的传热条件不仅与凝固冷却速度有关,而且取决于轴向温度梯度G_A与径向温度梯度G_R之比。等比值G_A/G_R增大,形成较好的轴向顺序凝固,则有利于偏析的减轻,可通过不同条件下凝固区域高度H的变化来分析。在液固两相区,表示自然对流特性的每数采用经达西公式修正的G~D_r准则。高度H愈小,G_r~D也愈小,因而形成沟槽偏析的枝晶间液相对流也愈小,对流的减小有利于沟槽偏析的减轻。
The heat transfer conditions for the formation of trench segregation in the steel ingot depend not only on the solidification cooling rate but also on the ratio of the axial temperature gradient G_A to the radial temperature gradient G_R. The ratio G_A / G_R increases to form a better axial order of solidification, which is beneficial to the reduction of segregation, which can be analyzed by the change of the height H of the solidified area under different conditions. In the liquid-solid two-phase region, each number indicating natural convection characteristics adopts the G ~ D_r criterion modified by Darcy’s formula. The smaller the height H is, the smaller the G_r ~ D is, so the smaller the convection between the dendrites forming the trench segregation is, and the smaller the convection is to the reduction of the trench segregation.