Al₂O₃–CaO-(MgO–SiO₂) inclusions are one of the dominant inclusions in Al-deoxidized spring steel, the compositions changes of which are closely related to refining slags and deoxidization process. The Al₂O₃–CaO–SiO₂–MgO system can represent the primary ingredients of the Al₂O₃–CaO inclusions. According to analyzed compositions and predicted liquidus temperature ranges of inclusions and refining slag, equilibra experiments under high temperature, water quenching technique and subsquent electron probe X-ray microanalysis (EPMA) has been conducted to ascertain detailed thermodynamic database for inclusions control. Liquidus temperatures within the dominant phase fields of Ca₃SiO₅, Ca₂SiO₄, CaAl₂O₄, Ca₃Al₄O₉, spinel and MgO with the intervals of 20 °C from 1350 to 1560°C were identified. To further promote inclusions control, the influences of mass ratios of Mass(Al2O3)Mass(Al2O3+SiO2+CaO) and MgO contents on equilibrated phases and liquidus temperature changes have been explored. To further enhance modification levels of Al₂O₃–CaO-(MgO–SiO₂) system inclusions, it is suggested that refining time could be suitably prolonged.

Al ₂ O ₃ -CaO-（MgO-SiO ₂）夹杂物是Al脱氧弹簧钢中的主要夹杂物之一，其成分变化与精炼渣和脱氧过程密切相关。Al ₂ O ₃ -CaO-SiO ₂ -MgO体系可以代表Al ₂ O ₃的主要成分–CaO夹杂物。根据夹杂物和精炼炉渣的成分分析和预测的液相线温度范围，进行了高温下的平衡实验，水淬技术和随后的电子探针X射线显微分析（EPMA），以确定用于夹杂物控制的详细热力学数据库。Ca ₃ SiO ₅，Ca ₂ SiO ₄，CaAl ₂ O ₄，Ca ₃ Al ₄ O ₉的主相场中的液相线温度鉴定出尖晶石和MgO在1350至1560°C之间的间隔为20°C。为了进一步促进夹杂物的控制，探索了质量比（Al2O3）质量（Al2O3 + SiO2 + CaO）和MgO的质量比对平衡相和液相线温度变化的影响。为了进一步提高Al ₂ O ₃ -CaO-（MgO-SiO ₂）系统夹杂物的改性水平，建议可以适当延长精炼时间。