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对铝镇静钢LF精炼钙处理后不同时期取钢样,通过SEM-EDS观察钢样中夹杂物,分析钙处理后铝镇静钢中夹杂物变性机制,并提出了一种夹杂物变性的碰撞机制:在钙处理后,由于钙浓度在钙气泡周围较高形成了CaO类夹杂物,其与钢液中已有的Al2O3类夹杂物相互碰撞结合在一起,然后二者发生化学反应变性为低熔点的液态夹杂物。通过相图分析从理论上指出:Al2O3类夹杂物可与CaO通过碰撞变性,且其变性机制和控速环节与Al2O3类夹杂物通过与钙发生还原反应的变性不同。夹杂物碰撞使变性速率大大加快,几分钟之内即可良好变性。在本次试验中,约有21%的Al2O3类夹杂物通过与CaO碰撞发生变性。实验室试验和其他研究者的工业试验结果均证明:在二次精炼过程中,通过往钢包中喂入CaO类粉末可以使Al2O3夹杂物变性。
The steel samples were taken from LF refined calcium-treated aluminum-killed steel at different periods and the inclusions were observed by SEM-EDS. The mechanism of inclusions degeneration in Al-killed steel after calcium treatment was analyzed and a collision mechanism of inclusions degeneration : After calcium treatment, CaO-like inclusions are formed around the calcium bubbles due to the calcium concentration, and they collide with the existing Al2O3-based inclusions in the molten steel, and then both chemically denature to a low melting point Of liquid inclusions. By phase diagram analysis, it is pointed out theoretically that Al2O3-based inclusions can be denatured by collision with CaO, and its denaturation mechanism and speed-controlling step are different from denaturation of Al2O3-based inclusions through reduction reaction with calcium. Impacts of inclusions so that the rate of degeneration greatly accelerated, within a few minutes to good degeneration. In this experiment, about 21% of Al2O3-based inclusions were denatured by collisions with CaO. Laboratory tests and industrial tests by other investigators have demonstrated that Al2O3 inclusions can be denatured by feeding CaO-based powders into ladle during secondary refining.