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为了研究坩埚材质对真空感应炉熔炼镍基合金Inconel 690纯净度的影响，在200、500kg真空感应炉上，分别使用镁质坩埚、钙质坩埚、铝镁质坩埚冶炼了Inconel 690合金，分析了产品中全氧含量、硫含量及氧化物夹杂数量、尺寸。真空感应炉铝镁质坩埚冶炼的产品全氧含量可达到(10~15)×10-6(质量分数，下同)，硫含量55×10-6，合金中存在粒径5~10μm的D类夹杂物和粒径50μm以下的B类夹杂物，产品纯净度较高。钙质坩埚冶炼的产品硫含量可达到10×10-6，全氧含量平均为33×10-6，合金中存在大量的粒径5~10μm的D类细小夹杂物，同时存在少量粒径50~100μm的大型钙硅酸盐夹杂物。镁质坩埚冶炼的合金中全氧、硫含量分别为28×10-6、55×10-6，存在大量粒径50μm以上的B类氧化物夹杂。Inconel 690合金通常采用真空感应炉加电渣重熔的工艺路线生产，不考虑硫含量对纯净度的影响，建议真空感应炉采用铝镁质炉衬冶炼Inconel 690合金。

Experiments of melting Inconel 690 by three different kinds of crucible material MgO, CaO, Al2O3 in 200 and 500kg VIM (Vacuum induction melting) were done. Sulfer and oxygen content ,oxidate sizes and number of the products were analyzed to study the effect of crucible material on purity of Ni-based alloy Inconel 690 melted by VIM. The results show that the oxygen content of product is lowest by melting in Al2O3 crucible, achieving (10-15)×10-6; There are 5-10μm D type oxidates amd less than 50μm B type oxidates in the ingot, the purity is high. The sulfer content of product is lowest by melting in CaO crucible, achieving 10×10-6, the average oxygen content is 33×10-6, there are lots of fine 5-10μm D type oxidates and some 50-100μm Ca-aluminate oxidates; The oxygen and sulfer content in the ingot melted by MgO crucible is 28×10-6 and 55×10-6 respectively. There are lots of B type oxidates larger than 50μm. Therefore, the Al2O3 crucible is the best choice to produce Inconel 690 by VIM.