材料期刊网

本文探讨了渣面温度对高温合金电渣重熔过程中Al,Ti控制的影响及金属熔池/渣池界面温度分布与锭表面质量的关系。 当结晶器对底水箱不绝缘时,渣面温度较高,熔炼后期氧从大气向渣中转移速度v_(s-g)~(O_2)比绝缘时大2—3倍;熔炼前期增Al倾向比绝缘时大。炉口电压增加,渣面温度升高,Ti烧损量加大。试验条件下,电压增加1V,Ti烧损量约增加0.03％。 金属熔池/渣池界面温度分布可用公式t=ae~(B/d) (B<0)来描述,它对电渣重熔锭表面质量具有决定性影响。文中提出了确定这一分布的方法。锭表面质量可用重熔过程中渣皮厚度的变化来衡量。渣皮厚度δ=B/(1nt_l-1na)。渣池内电流密度分布及结晶器壁附近的热传导条件、渣的液相线温度以及所有影响“高温区间”温度的因素的变化均可导致锭表面质量的改变。

The effect of temperature at slag face on A1 and Ti control and the relation between temperature distribution round liquid metal pool/molten slag pool interface and quality of ingot surface have been investigated during ESR process of superalloy. If the insulation of the mould from its base plate was poor and rather higher temperature appeared at slag face, in the later refining stage the rate of O_2 penetration to slag from atmosphere,ν_(s—g)~(O2),is 2—3 times faster and also in the earlier stage the tendency towards the A1 increasing is greater than that of good insulation. An increase in voltage may cause the temperature at slag face to rise and the Ti loss to accelerate, e.g. every 0.03% more Ti loss at nearly 1 V increased.The temperature distribution round liquid metal pool/molten slag pool interface may be expressed by t=ae~(B/d)(B<0), it has a great influenc upon the quality of ingot surface. The method to ascertain this temperature distribution is presented.The evaluation of quality may be proposed by the change of slag coating thickness, δ=B/(ln t_1—lna). It is shown that the quality of ingot surface is perhaps depended on the electric current distribution in the molten slag pool, the heat conducting conditions at mould wall, the liquidus temperature of slag and the change of all factors affecting the temperature at "high temperature region".