材料期刊网

探讨了铸坯中一次枝晶间距的变化规律及其“鼓肚”量对枝晶间距的影响。通过确定凝固速度的表达式，定量计算了连铸过程中一次枝晶间距。结果表明，“鼓肚”的存在，使柱状晶生长初期一次枝晶间距出现增大、减小、再增大的周期性变化趋势，当固液界面向正弦波的波峰处运动的过程中，一次枝晶间距逐渐增大，当固液界面向正弦波的波谷处运动的过程中，一次枝晶间距逐渐减小。“鼓肚”量增加时，一次枝晶间距变化的幅度增大。在凝固的中后期，波峰和波谷处的一次枝晶间距基本相等，表明枝晶进入稳定生长的阶段，此时“鼓肚”对枝晶间距的影响基本可以忽略。计算结果与实验结果基本吻合。

The variation rule of the primary dendritic spacing in the casting blanks and the effect of the bulge size on dendritic spacing were studied. Based on the conformation of the solidification rate expression, the quantitative calculation of the primary dendritic spacing in the continuous casting was done. The results show that the bulge makes the primary dendritic spacing generate the periodic change of the increase and the decrease in the first stage of the columnar crystal growth. The primary dendritic spacing increased gradually as the solidliquid interface moved to the wave crest of the sine wave, and the primary dendritic spacing decreased gradually as the solidliquid interface moved to the wave hallow of the sine wave. The amplitude of variation added as the increase of the bulge size. The effect of the bulge on the primary dendritic spacing could be ignored in the intermediate stage and in the late stage of the solidification, the primary dendritic spacing was equal at the positions of the wave crest and the wave hollow, indicating that the dendrite started the stable growth. The calculated results basically agreed with the experimental results.