Abstract: An analysis on cracking and perforation defects occurred in 230 ~ 400 mm plates rolled from 28 ~40 t ingot of low carbon steel S355JR and S355J2 (/% ： 0. 17 ~0. 20C, 0. 30 ~0. 55Si, 1.40 - 1.60Mn, W0.020P, W0.015S, 0. 020 ~ 0. 040Al, 0. 020 ~0. 030Nb) is carried out. With the optimum process measures including increasing level of operation crews, controlling ingot body and hot top casting speed according to overheating extent of liquid, controlling refining end [O] ≤ 25 x 10^-6 and aluminum content in steel 0. 020% 〜0. 040%, the ingot qualified ratio by nondestructive testing increases to 96. 8%.

摘要： 分析了S355JR和S355J2低碳钢(/%:0.17～0.20C、0.30～0.55Si、1.40～1.60Mn、≤0.020P、≤0.015S、0.020～0.040A1、0.020～0.030Nb)28～40 t钢锭轧成230～400 mm钢板出现的开裂和穿孔缺陷。通过提高浇钢工操作水平,根据钢水过热度控制本体浇铸和帽口浇铸时问;控制精炼终点[O]≤25×10^-6以及钢中铝含量0.020%～0.040%等优化浇铸工艺措施使钢锭探伤合格率提高到96.8%。

关键词: 低碳钢, 28 ~40 t大型钢锭, 厚板, 轧板开裂, 穿孔缺陷, 工艺优化