Q235板坯角部裂纹缺陷的成因分析与控制措施  

Analysis and control measures of the corner crack defects in Q235 slab

作　　者：赵建强[1] 苏瑞先 ZHAO Jianqiang;SU Ruixian(Steel-making Plant,Shanghai Meishan Iron&Steel Co.,Ltd.,Nanjing 210039,Jiangsu,China)

机构地区：[1]上海梅山钢铁股份有限公司炼钢厂,江苏南京210039

出　　处：《宝钢技术》2024年第6期46-49,共4页Baosteel Technology

摘　　要：对梅钢板坯连铸机生产的热轧结构钢Q235角部裂纹缺陷进行了分析,研究表明该缺陷形成的主要原因为Q235钢种碳元素含量设计不合理及氮化物析出降低了基体的高温塑性。原成分设计中,氮化铝易在奥氏体晶界析出,导致铸坯经过矫直区时产生应力集中破坏钢基体的连续性,从而形成裂纹。通过对Q235钢种成分设计优化、降低连铸二冷强度、优化保护渣性能、铸机设备精度提升等措施,Q235板坯角部裂纹缺陷得到有效控制,缺陷发生指数由4.3下降到0.9。The crack defects at the corners of the hot-rolled structural steel Q235 produced by Meishan Iron&Steel Co.,Ltd.were investigated.The research result shows that the main reasons for the formation of this defect are the unreasonable carbon content of Q235 steel and the influence of aluminum nitride precipitation on the high-temperature plasticity of the matrix.In the original composition design,aluminum nitride tends to precipitate at the austenite grain boundary,causing stress concentration and damage to the continuity of the steel matrix when the slab passes through the straightening zone,thereby forming cracks.Through measures such as optimizing the composition design of Q235 steel,reducing the secondary cooling strength of continuous casting,optimizing the performance of protective slag,and improving the precision of casting equipment,the corner crack defects of Q235 steel slabs have been effectively controlled,with the defect occurrence index dropping from 4.3 to 0.9.

关 键 词：结构钢 连铸 Q235 角部裂纹 

分 类 号：TF777.1[冶金工程—钢铁冶金]