Si对高Si／C比灰铸铁奥氏体枝晶数量的影响规律

Effect of Si on the Quantity of Austenite Dendrite in High Ratio Si/C Grey Iron

本文运用定向凝固方法，在不同冷却条件下对不同成分灰铸铁的凝固过程运用微分仪进行热分析．结果表明：在碳当量相同的条件下，随着Ｓｉ／Ｃ比的提高，Ｆｅ－Ｃ－Ｓｉ合金的最小共晶凝固温度升高．并进一步分析了Ｓｉ使高Ｓｉ／Ｃ比灰铸铁奥氏体枝晶数量增加的原因，提出了Ｓｉ促使灰铸铁共晶共生区向右偏移的一论断，并利用出现奥氏体枝晶的临界冷却速度，半定量地描绘出了硅使得共晶共生区向右偏移的曲线．

In this paper the directional solidified grey iron of various carbon equivalent were thermodynamically analyzed, and the results show:under the condition of similar carbon equivalent, as the Si/C ratio increases the minimum eutectic solidification temperature of Fe-C-Si alloy rises,and the quantities of austenite dendrite are increased.Further analysis shows:the mechanism of increased quantities of austenite dendrites is that silicon makes the eutectic coupled zone move to the right in the Fe-C phase diagram.