【摘要】：以A356回爐料為對象,研究了熔煉溫度和保溫時間對Ca含量的變化規(guī)律。結果表明:Ca含量隨著保溫時間延長以二次曲線規(guī)律逐漸下降,低溫時下降速率線性增大,高溫時下降速率線性減小。當熔煉溫度升高,Ca含量下降速率加快,在760℃熔煉時只經過3h就能達到最低含量6×10~(-6)。通過熱力學和動力學分析可知,[Ca]主要通過前期被氧化和中后期擴散至熔體表層還原氧化鋁的方式降低。溫度越高,[Ca]與氧化鋁開始反應的時間越短。在660~720℃熔煉初期,Ca氧化速率隨溫度變化滿足K=578 749exp[-176 500/(RT)]規(guī)律。
[Abstract]:The effect of melting temperature and holding time on the content of Ca was studied by taking A356 recharging material as an object. The results showed that the content of Ca decreased gradually with the prolongation of the holding time, the decrease rate increased linearly at low temperature, and decreased linearly at high temperature. When the melting temperature is increased, the decrease rate of Ca content is accelerated, and the lowest content of 6 脳 10 ~ (- 6) can be achieved only after 3 hours of melting at 760 鈩，

本文編號：2468252