提高RH真空处理的精炼效率

INCREMENT OF REFINING EFFICIENCY FOR RH VACUUM TREATMENT

在８０ｔ的ＲＨ装置上采用增大上升管氩气流量（４００Ｌ／ｍｉｎ→６６０Ｌ／ｍｉｎ）的方法进行真空精炼工艺试验。结果表明：［Ｃ］达到２０ｐｐｍ的脱碳时间缩短３ｍｉｎ；［Ｈ］降至１ｐｐｍ；添加５ｋｇ／ｔ熔剂，脱硫效率为６０％。用环流模型分析了钢水循环流量的变化。增大插入管内径和氩气流量都能明显改善钢水环流，但氩气流量接近１０００Ｌ／ｍｉｎ时，环流趋于饱和；进一步提高循环流量需要扩大插入管内径。为稳定操作并考虑耐火材料有效厚度，插入管内径选择０．３５ｍ，６６０Ｌ／ｍｉｎ的氩气流量可获得４０ｔ／ｍｉｎ钢水循环流量，比设计指标提高３３％。

The vacuum refining process tests at a 80 t RH unit have been carried out using the method of increasing argon flow rate (from 400 L/min to 660 L/min) in the upleg.The results show that decarburization time can be shortened by 3 min with carbon content up to 20 ppm,hydrogen content can be lowered to 1 ppm and desulphurisation efficiency is at 60% by adding 5 kg/t flux.The changes of circulation rate have been analysed using a circulation flow model. Enlarging the snorkel inner diameter and increasing the argon flow rate can improve the circulation rate of molten steel remarkably.However,the circulation rate will tend to saturation when argon flow rate is close to 1000 L/min.Enlarging the snorkel inner diameter is needed for farther increasing the circulation rate. In order to stabilize the operations and consider the effective thickness of refractory,it is possible to obtain the circulation rate of molten steel at 40 t/min by selecting snorkel inner diameter of 0.35 m with argon flow rate up to 660 L/min, which is 33% higher as compared with the design index.