120t BOF-LF-RH-CC流程冶炼石油套管钢时TiN的析出和控制  

Precipitation and Control of Titanium Nitride in Oil Casing Tube Steel Steelmaking by 120 t BOF-LF-RH-CC Flow Sheet

作　　者：方忠强[1] 孙彦辉[1] 汪成义[1] 蔡开科[1] 

机构地区：[1]北京科技大学冶金与生态工程学院,北京100083

出　　处：《特殊钢》2014年第5期30-33,共4页Special Steel

基　　金：国家自然科学基金资助项目(51274032)

摘　　要：石油套管用钢(/%:0.26~0.29C,0.25~0.35Si,0.40~0.50Mn,≤0.009P,≤0.004S,0.95~1.05Cr,0.09~0.11V,0.02~0.04Al,0.015~0.020Ti,≤0.006 0N)的生产流程为铁水预处理-120 t BOF-吹氩-LF-喂CaSi线-RH-合金化-喂CaSi线-软吹氩-Φ220 mm圆坯连铸工艺。通过热力学分析得出钢中N含量超过50×10^(-6)以及工业试验得出生产的圆铸坯中的N含量为67×10^(-6)时,在铸坯中易形成2μm以上的TiN夹杂。通过控制BOF终点[N]≤30×10^(-6),LF终点[S]≤25×10^(-6),[O]≤25×10^(-6),[N]≤35×10^(-6),RH合金化后终点[N]≤35×10^(-6),[H]≤1.5×10^(-6),稳定喂CaSi线速度300~400 m/min,控制中间包[N]≤40×10^(-6),严格连铸保护浇铸工艺,则铸坯中的N含量≤50×10^(-6),钢中TiN夹杂数量显著下降,未发现大尺寸TiN夹杂物。The production flow sheet for oil casing tube steel （/% ： 0. 26 -0. 29C, 0. 25 - 0. 35Si, 0. 40 -0. 50Mn, ≤0. 009P, ≤0. 004S, 0. 95 - 1.05Cr, 0. 09 -0. llV, O. 02 -0. 04A1, 0. 015 -0. 020Ti, ≤0. 006 ON） is hot metal pretreat- ment-120 t BOF-argon blowing-LF-CaSi wire feeding-RH-Alloying-CaSi wire feeding-soft argon blowing-Ф200 mm round bloom casting process. By commercial test as the N content in produced round casting bloom is 67 x 10^-6 and by thermodynamic analysis as the N content in steel is more than 50 × 10^-6, the more than 2 μm TiN inclusions easily form in casting bloom. With controlling BOF end [ N] ~〈30 x 10^-6, LF end [ S] ≤25 × 10^-6, [ O] ~〈25 x 10^-6 and [ N] ≤35 x 10^-6, after alloying RH end [N] ~〈35 x 10^-6 and [H]≤1.5 × 10^-6, stably feeding CaSi wire speed 300 -400 m/min and controlling tundish [N] 10^-640 × 10^-6 and strict casting-shielding process, the N content in casting bloom shall be ≤50 × 10^-6 , the a- mount of TiN inclusions in steel decreases markedly and there are not larger size TiN inclusions to be found in steel.

关 键 词：120t BOF-LF-RH-CC 石油套管钢 TIN 热力学计算 氮含量 

分 类 号：TF764[冶金工程—钢铁冶金]