Abstract: The production flow sheet for Φ500 mm casting bloom of 0.20% C steel (0.19% ~ 0.23% C) is 70 t BOF-LF-VD-Φ500 mm heavy round caster. The study and optimization work on mechanical equipment and process parameters including secondary water cooling parameter have been carried out. In first pilot production with continuous casting 8 heats of 0.20% C steel, the optimizing parameters including using special mold powder, controlling liquid overheating extent 25 ~35 °C , casting speed 0.30 m/min, secondary water rate 0.14 L/kg, mold electromagnetic stirring 400 A/1.5 Hz are used. The examination results show that the bloom surface has not visible defects including bulging, feather defect； the rating of center line shrinkage is 0.5 and the rating of center porosity is 1 , the carbon segregation is ≤1.12, and the oxygen content in steel ≤15 x 10^-6, nitrogen content in steel ≤65 x 10^-6 to meet the requirement of design.

Key words: Φ500 mm Round Casting Bloom, Pilot Production, 0. 20% C Steel, Production Practice

摘要： 20钢(0.19%～0.23%C)Φ500 mm铸坯的生产流程为70 t转炉-LF-VD-Φ500 mm大圆坯连铸机从机械设备和二冷参数等方面进行研究和优化第1次生产试验连续浇铸8炉20钢,采用的优化工艺包括使用专用结晶器保护渣,控制过热度25～35℃,拉速0.30 m/min,比水量0.14 L/kg,结晶器电磁搅拌400 A/1.5 Hz等。检验结果表明,铸坯表面无可见冷疤、鼓肚等缺陷,中心缩孔0.5级,中心疏松1级,碳偏析≤1.12,钢中氧含量≤15×10^-6,氮含量≤65×10^-6,达到设计要求。

关键词: Φ500 mm圆铸坯, 试生产, 20钢, 生产实践