CAS-LF-VD精炼过程82A帘线钢中夹杂物的转变

研究的0.80%~0.82%C帘线钢的生产流程为80 t:BOF-CAS-LF-VD-150 mm×150 mm CC工艺。通过顶底复吹转炉出钢过程加入300 kg金属锰和200 kg高纯硅进行硅锰复合脱氧,LF过程先造碱度(CaO/SiO2)2.04的精炼渣,再将精炼渣碱度(CaO/SiO2)降至0.86,保持渣中Al₂O₃含量为~5%,来控制钢中非金属夹杂物的塑性转变。结果表明,铸坯平均总氧含量为16×10^-6,氮含量控制在50×10^-6左右,CAS(密封吹氩调成分)过程钢中夹杂物主要是MnO-Al₂O₃-SiO₂;LF、VD过程钢中和铸坯中夹杂物主要是CaO-Al₂O₃-SiO₂-MgO系,该类夹杂物尺寸偏小(2~3μm),分布在1 400℃低熔点区域附近。

Transformation of Inclusions in Steel 82A for Tire Cord during CAS-LF-VD Refining Process

The production flow sheet for studied 0. 80% ~0. 82% C Steel for tire cord is 80 t BOF-CAS-LF-VD-150 mm x 150 mm CC process. With adding 300 kg manganese metal and 200 kg high purity silicon during top and bottom blown converter tapping to silicon-manganese combined deoxidize, during LF refining first slagging refining slag with basicity (CaO/SiO₂ )2. 04 then decreasing the basicity ( CaO/SiO₂) to 0. 86 and maintaining -5% Al₂O₃ content in slag to control the plasticity transformation of nonmetallic inclusions in steel. Results show that the average total oxygen content in casting billet is 16 X 10^-6 and the nitrogen content in billet is controlled about 50 x 10^-6 , during CAS ( Composition adjustment by sealed argon bubbling) process the main inclusions in steel are MnO-Al₂O₃-SiO₂ , in LF and VD process, and in casting billet the main inclusions are CaO-Al₂O₃ -SiO₂ -MgO series, the size of that inclusion series is smaller i. e. 2 ~ 3 μm, which distribute near the 1 400 °C low melting zone.