摘要
为了控制26CrMo7S钢中夹杂物,提高钢材机械性能,采用全流程洁净度分析,探究了某厂EAF→LF→VD→CC工艺流程夹杂物演变规律。结果表明,LF进站夹杂物主要是由Al2O3、MgO和CaS结合的成分不均匀、形貌不规则的复合夹杂物。LF、VD精炼处理后,主要是以Al_(2)O_(3)、MgO和CaO、CaS形成不均匀的多边形或近球形复合夹杂物,且CaO含量持续增加。钙处理后,夹杂物进一步球化,主要成分为以CaS包裹的氧化物均匀复合夹杂物。采用EAF-LF-VD-CC工艺,夹杂物数密度呈先降低再升高趋势,在VD工序数密度降至最低16.1个/mm^(2),平均尺寸呈现先增加后减小的趋势,在VD工序尺寸达到最大值2.83μm。LF精炼时间短、钙处理不合理、连铸二次氧化是导致钢液中夹杂物超标的主要原因。适当增加LF处理时间、保证充足的弱搅拌、探明合适的钙处理“窗口”、保证夹杂物变性的同时不会过量引入CaO夹杂、连铸工序采用氩封、中间包氩气吹扫等保护手段可以有效提高钢液洁净度。
In order to control the inclusions in 26CrMo7S steel and improve the mechanical properties of the steel,the cleanliness analysis of the whole process was used to explore the evolution of inclusions in the EAF→LF→VD→CC process of a mills.The results show that the LF pitted inclusions are mainly composed of Al_(2)O_(3),MgO and CaS combined with uneven composition and irregular morphology.After LF and VD refining,Al2O3,MgO,CaO,and CaS form non-uniform polygonal or nearly spherical composite inclusions,and the continuous increase of the CaO content.After calcium treatment,the inclusions were further spheroidized,and the main components were uniform composite inclusions of oxides wrapped with CaS.In the EAF-LF-VD-CC process,the number density of inclusions first decreased and then increased,and the number density decreased to a minimum of 16.1 mm^(-2)in the VD process,and the average size showed a trend of first increase and then decrease,and the size in the VD process A maximum value of 2.83μm is reached.The LF refining time is short,the calcium treatment is unreasonable,and the secondary oxidation of continuous casting is the main reason for the excessive inclusions in the molten steel.Increasing LF processing time appropriately,ensuring sufficient weak stirring,finding out appropriate calcium treatment“window”,ensuring the inclusion denature and not excessive introduction of CaO inclusion,using argon sealing,tundish argon blowing protection means in continuous casting process can effectively improve the cleanliness of liquid steel.
作者
焦傲腾
杨树峰
李京社
宋景凌
李恒华
张福君
JIAO Ao-teng;YANG Shu-feng;LI Jing-she;SONG Jing-ling;LI Heng-hua;ZHANG Fu-jun(School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China;Steelmaking Branch,Hengyang Valin Steel Tube Co.,Ltd.,Hengyang 421001,Hunan,China)
出处
《连铸》
2023年第2期28-33,共6页
Continuous Casting
基金
国家自然科学基金资助项目(51734003,51874024)。
