Abstract: In order to improve the problem of nozzle clogging and poor continuous castability of 55Cr3 spring steel with aluminum deoxidation during continuous casting， the evolution of inclusions precipitation in different adding value of calcium lines are discussed and industrial test are carried out. The experimental results show that the light calcium treatment of 55Cr3 steel by reducing the length of the calcium line from 100 m to 50 m， to control the calcium content of the molten steel to about 0.001 7% and the oxygen content to about 0.002 6%， on the overall， the melting point of the average composition of inclusions at 1 600 ℃ is close to the liquid phase line， the area density of CaS inclusions is less than 0.7 pcs·mm^-2， the problem of nozzle clogging has been improved， the average number of successive pouring heats has been increased from 5-6 to 8-10 heats， and the qualified rate of inclusions grading result is above 98 %， and the light calcium treatment technology has achieved better results.

Key words: Calcium Treatment, 55Cr3 Spring Steel, Thermodynamic Calculations, Industrial Tests, Inclusions, Number of Continuous Casting Heats

摘要： 为改善铝脱氧55Cr3弹簧钢连铸过程水口结瘤和连浇性差问题，讨论了不同钙线加入量时夹杂物的演变规律并开展工业试验。结果表明，将55Cr3钢的喂钙线长度由100 m减少到50 m的轻钙处理，钢液中钙含量控制到0.001 7%左右，氧含量约为0.002 6%，整体上夹杂物平均成分的熔点靠近1 600 ℃液相线，CaS夹杂物的面积密度小于0.7 个/mm²，水口结瘤问题得到了改善，平均连续浇注炉数从5～6炉提高到8～10炉，并且夹杂物评级结果合格率高达98%以上，轻钙处理技术取得了较好的效果。

关键词: 钙处理, 55Cr3弹簧钢, 热力学计算, 工业试验, 夹杂物, 连烧炉数