Abstract: The effects of process and different calcium treatment methods on Ca/S and inclusions in steel and the effects of low superheat match and dynamic soft reduction technology on macrostructure quality of billets of acid resistant steel Q345R smelting by “BOF-LF-RH-CC" process are analyzed. Research shows that"LF + RH + calcium treatments" process can significantly increase the Ca/S in molten steel and reduce the size of A and B inclusions in steel. As calcium treatment is carried out after RH breaking vacuum, the class 2. 0 Ds inclusions appear in finished plate, but the size and quantity of these inclusions can be reduced by prolonging the soft blowing time. With LF/RH two steps calcium treatments process and soft blowing time for 16 ~20 min after RH calcium treatments, the inclusion size of B, Ds, D can be controlled ≤1.0 rating and the inclusion size of A,C can be controlled ≤0.5 rating in steel plates. Core segregation of billet macrostructure rating is C type 1.0 by 5 〜12℃ superheat casting match and dynamic soft reduction technology, the segregation rating of each elements is low. Using the process, the composition, inclusions and macrostructure quality can meet the acid resistant steel Q345R requirements.

摘要： 分析了"BOF-LF-RH-连铸"生产Q345R抗酸钢的工艺和不同的钙处理方式对钢Ca/S、夹杂物的影响,以及低过热度结合动态轻压下浇铸对铸坯低倍质量的影响。研究表明:采用"LF+RH+钙处理"工艺冶炼,可提高钢中Ca/S,降低钢中A类和B类夹杂物尺寸。RH真空后进行钙处理,成品钢板中出现2.0级的Ds类夹杂,延长钙处理后软吹时间,可减少该类夹杂的尺寸和数量。采用LF/RH双步钙处理工艺,RH钙处理后软吹时间16～20 min,可达到钢板B类、Ds和D类夹杂尺寸控制在≤1.0级,A类和C类夹杂尺寸控制在≤0.5级。利用5～12℃过热度结合动态轻压下技术浇铸,铸坯低倍评级中心偏析达到C类1.0级,各元素偏析度较低。采用该工艺,可实现Q345R抗酸钢成分、夹杂物、低倍质量满足标准要求。