10B21含硼冷镦钢轧后结疤成因分析及工艺改进

通过实验及热力学分析得出，轧制10B21钢结疤形成主要原因为钢中平均N含量为127×10^-6,导致铸坯角部冷却过程中在奥氏体晶界析出细小的BN和AlN夹杂，增加了铸坯的裂纹敏感性，形成铸坯裂纹。通过提高铁水比≥920 kg/t、转炉终点C-T-P(碳-温度-磷)命中率≥85%、出钢口圆流出钢以及LF加热次数≤3次，时间≤25 min等措施可将钢中的氮含量稳定控制在≤50×10^-6,有效避免10B21钢轧后盘条结疤，提高成材率，降低成本。

Forming Reason and Process Improvement of Seab Defects Rolled Boron-bearing Cold Heading Steel 10B21

Through experiments and thermodynamic analysis, it is obtained that the main cause of the scab forming of rolled 10B21 steel is the average nitrogen content in steel being 127 x 10^-6 , lead to the precipitation of fine BN and AIN inclusions at the austenite grain boundary at the comer of cast billet during cooling, increasing the crack sensitivity of the billet and forming the billet crack, the nitrogen content in steel can be stably controlled below 50 x 10^-6 by increasing the consumption of molten iron ≥ 920 kg/t, increasing the C-T-P ( Carbon-Temperature-Phosphorus) hit rate ≥ 85% at the end of die converter, discharging steel from the outlet round, healing number of times of LF ≤ 3 time, and ≤ 25 minutes casting. It can effectively prevent wire rod scarring of 10B21 steel after rolling to improve the yield of rolled steel and to reduce the production cost.