Abstract: In order to control the serious loss of Ti element during electroslag remelting of NiCrMoV alloy steel， the effect law of different slag systems on the chemical composition of ESR ingot， the number， composition， and size distribution of inclusions in electroslag ingots were investigated through laboratory experiments and thermodynamic calculation. The results showed that the content of total oxygen in ESR ingots obviously increased after electroslag remelting and it was increased from 15.1×10^-6 in consumable electrode to （31.3-42.1）×10^-6 in ESR ingots. The number density of inclusions was increased to 6.54-15.95 PCS/mm². However， the content of nitrogen was almost unchanged. When the slag systems 70%CaF₂-30%Al₂O₃ and 55%CaF₂-25%Al₂O₃-17%CaO-3%MgO were adopted， the Ti loss in ESR ingots became serious and the inclusions were mainly Al₂O₃. Furthermore， the Ti loss in ESR ingots could be controlled when a certain amount of TiO₂ was added to the slag. The types of inclusions were mainly composed of Al₂O₃， Al₂O₃-CaO-TiO₂， and other oxides. The content of TiO₂ in inclusions was obviously increased. Besides， the mechanism of stabilizing Ti content in ESR ingots by adding TiO₂ to the slag was revealed through thermodynamic calculation. Based on the cleanliness of ESR ingots after electroslag remelting， the composition of the appropriate slag system （50%CaF₂-25%Al₂O₃-17%CaO-3%MgO-5%TiO₂） was determined.

Key words: NiCrMoV Alloy Steel, Electroslag Remelting （ESR）, Slag System, Cleanliness, Thermodynamic Calculation

摘要： 针对NiCrMoV合金钢电渣重熔过程中Ti元素的烧损严重问题，通过实验室实验和热力学计算研究了不同渣系对电渣锭化学成分及夹杂物数量、成分和尺寸分布的影响规律。结果表明，电渣重熔后电渣锭中总氧含量明显增加，由自耗电极的15.1×10^-6增加至（31.3～42.1）×10^-6，夹杂物数密度增加至6.54～15.95个/mm²，而氮含量变化不大；采用渣系70%CaF₂-30%Al₂O₃和55%CaF₂-25%Al₂O₃-17%CaO-3%MgO时，电渣锭中Ti元素的烧损严重，夹杂物以Al₂O₃为主，渣相中添加一定量的TiO₂能较好地控制重熔后Ti的烧损，夹杂物类型主要由Al₂O₃、Al2O₃-CaO-TiO₂、其他氧化物夹杂组成，且夹杂物中TiO₂含量明显增加；通过热力学计算，揭示了渣相中添加TiO2对稳定电渣锭中Ti元素含量的作用机理；综合考虑重熔后电渣锭的洁净度水平，确定了合适的电渣重熔渣相成分（50%CaF₂-25%Al₂O₃-17%CaO-3%MgO-5%TiO₂）。

关键词: NiCrMoV合金钢, 电渣重熔, 渣系, 洁净度, 热力学计算