摘要
对X70管线钢进行了六炉钙处理实验.结果表明:钙处理后管线钢生产的后续工序中钢中钙含量显著下降,夹杂物组成和形貌发生显著变化;二次氧化会降低管线钢钙处理效果,但钢中溶解钙和较高CaO含量的CaO-Al2O3复合夹杂可对钢水二次氧化产生的Al2O3发生改性作用;高级别管线钢钙处理效果与钢中钙含量、氧含量、硫含量、钢水二次氧化程度以及钙处理后续时间等有关,采用钢中Ca含量、[%Ca]Tot/[%Al]s、[%Ca]Tot/T[O]、ACR和[%Ca]Tot/[%S]作为钙处理效果的评判标准均存在缺陷.本文建议钙处理效果评判标准为:①铸坯中心部位或轧后板带中心部位不存在单纯的MnS夹杂;②中间包和结晶器中夹杂的nCaO/Al2O3应该与12CaO.7Al2O3相近;③钙处理后夹杂的nCaO/Al2O3应稍高于12CaO.7Al2O3的夹杂.同时还必须注意钙处理应在最后精炼工序的后期进行,尽量防止钢水的二次氧化.
Calcium treatment experiments were carried out on six heats of X70 pipeline steel.The results show that the Ca content of the steel dropped a lot and the composition and morphology of inclusions varied obviously in producing the steel after calcium treatment.Reoxidation deteriorates the effect of calcium treatment,but dissolved calcium and CaO-Al2O3 compound inclusions with high CaO content can play a role of modification on Al2O3 caused by reoxidation.The calcium treatment effect of high grade pipeline steel is related with the concentrations of calcium,oxygen and sulphur,reoxidation degree,and time after treatment,but evaluating calcium treatment with calcium content,[%Ca]Tot/[%Al]s,[%Ca]Tot/T[O],ACR and [%Ca]Tot/[%S] is improper.A evaluation standard is put forward as the following：（1） pure MnS inclusions do not exist in the central area of slabs or rolled plates,（2） nCaO/Al2O3 of inclusions in the tundish and mould is controlled around that of 12CaO·7Al2O3,and （3） nCaO/Al2O3 of inclusions after calcium treatment is higher than that of 12CaO·7Al2O3.It is also be careful that calcium treatment is carried out at the end of the final refining procedure so as to prevent reoxidation of liquid steel.
出处
《北京科技大学学报》
EI
CAS
CSCD
北大核心
2010年第3期312-318,共7页
Journal of University of Science and Technology Beijing
基金
"十一五"国家科技支撑计划资助项目(No.2006BAE03A06-1)
关键词
钙处理
管线钢
夹杂物改性
二次氧化
评价标准
calcium treatment
pipeline steel
inclusion modification
reoxidation
evaluation standard
