高压锅炉管用钢P11 Φ250～350mm连铸圆坯的开发

开发的P11钢(/%:0.08~0.14C,0.65~0.85Si,0.40~0.60Mn,≤0.010P,≤0.010S,1.10~1.30Cr,0.46~0.60Mo,≤0.015Alt)连铸圆坯的生产流程为KR铁水预处理-70 t顶底复吹转炉-LF-VD-圆坯连铸工艺。通过控制/%:0.09~0.11C,1.15~1.20Cr,0.07~0.08P,0.002~0.005S,0.008~0.015Als,中间包钢液温度(1 538±5)℃,连铸拉速0.70~1.05 m/min,二次冷却比水量0.35~0.40 L/kg,矫直温度≥900℃,缓冷坑温度≥500℃等工艺措施,检验结果表明,铸坯表面质量合格,缩孔≤0.5级,中心疏松≤1.0级,钢P含量为0.007%~0.008%,S含量0.002%~0.005%,该钢在工作温度下有较好的耐流动加速腐蚀性(FAC)。