Abstract: Based on analyzing the effect of calcium treatment on inclusion modification and combined commercial pilot production of pipeline steel X80 (%： ≤0.08C, ≤1.85Mn, ≤0.060Als) in steelworks, the limits of calcium content required for modifying Al₂O₃ to low-melting-point calcium aluminate and the limits of sulphur content to avoid single phase CaS precipitation are analyzed and calculated by using the metallurgical thermodynamics principle, and after RH treatment of liquid containing ≤0.002% S and 0.025%~0.035% Al and calcium treated by feeding Ca-Si wire according finishing [Ca]_Tot = (40 ~50) x 10^-6 calculation, the examination of inclusions in liquid of tundish and in casting billet has been carried out. Results show that the average [Ca]_Tot for test heats of pipeline steel X80 is 41 x 10^-6 and [S] is 23 x 10^-6 that are within the limits calculated by theory, and the most inclusions in calcium treated steel are compound inclusion CaO- CaS-Al₂O₃ to get better result of calcium treatment.

Key words: Inclusion, Modification, Pipeline Steel, Calcium Treatment

摘要： 在钙处理对夹杂物变性作用进行分析的基础上,结合钢厂生产X80管线钢(%:≤0.08C、≤1.85Mn、≤0.060Als)的工业性试验,利用冶金热力学原理,分析计算了Al₂O₃变性为低熔点钙铝酸盐所需钙含量的范围和避免单相CaS析出硫含量的范围,同时对≤0.002%S和0.025%～0.035%Al的RH处理钢水按出站[Ca]_Tot=(40～50)×10-6计算喂Ca-Si线进行钙处理,并对中间包钢水和铸坯中的夹杂物进行了检测。结果表明,X80管线钢试验炉次平均[Ca]_Tot为41×10^-6,[S]为23×10^-6,均在理论计算范围内;同时经钙处理后,钢中绝大部分夹杂物CaO-CaS-Al₂O₃复合夹杂,钙处理效果良好。

关键词: 夹杂物, 变性, 管线钢, 钙处理