This work aims to clarify the evolution and formation mechanisms of non-metallic inclusions during protective argon gas atmosphere electroslag remelting (ESR) of a low-aluminum 9 mass pctCr heat-resistant steel. The pickup degree of both boron and aluminum in liquid steel during protective argon gas atmosphere ESR was lowered with increasing the SiO₂ content of the slag through inhibiting steel–slag reactions. A kinetic model for describing and predicting oxide inclusion removal by slag adsorption was developed. The oxide inclusions from the steel electrode (quaternary MnO-SiO₂-Al₂O₃-CaO) were fully removed through dissociating into their specific chemical species in liquid steel in parallel with absorbing those undissociated inclusions into molten slag before liquid metal droplets enter into the liquid metal pool. The critical sizes of the oxide inclusions through different removal ways in the ESR process were determined. A part of patch-type MnS inclusions was dissociated into soluble sulfur and manganese in liquid steel, whereas the others dissolved into oxide inclusions during the ESR. The inclusions in the liquid metal pool and ingots are the newly born Al₂O₃ (around 80 pct in number fraction) and CaO-Al₂O₃. The formation of oxide inclusions during the cooling and solidification of liquid steel leads to an increase in both the size and number density of inclusions.

本工作旨在阐明低铝 9 质量 pctCr 耐热钢在保护性氩气气氛电渣重熔 (ESR) 过程中非金属夹杂物的演变和形成机制。通过抑制钢渣反应，随着渣中SiO ₂含量的增加，在氩气保护气氛ESR中钢液中硼和铝的吸收度降低。建立了描述和预测通过炉渣吸附去除氧化物夹杂物的动力学模型。来自钢焊条的氧化物夹杂物（四元MnO-SiO ₂ -Al ₂ O ₃-CaO) 在液态金属液滴进入液态金属熔池之前，通过在钢液中解离成其特定的化学物质，同时将那些未解离的夹杂物吸收到熔渣中来完全去除。确定了ESR工艺中不同去除方式的氧化物夹杂物的临界尺寸。部分斑块型 MnS 夹杂物在钢液中解离为可溶性硫和锰，而其他部分则在 ESR 过程中溶解为氧化物夹杂物。液态金属熔池和铸锭中的夹杂物是新生的 Al ₂ O ₃（数量分数约为 80%）和 CaO-Al ₂ O ₃. 钢液冷却和凝固过程中氧化物夹杂物的形成导致夹杂物尺寸和数量密度的增加。