Q235B热轧带钢冷弯开裂原因分析及措施  

Reason Analysis and Measures for Cold Bending Cracking of Q235B Hot Rolled Strip

作　　者：李晓冬 李亮[1] 赵文 金柱元 Li Xiaodong;Li Liang;Zhao Wen;Jin Zhuyuan(Rizhao Iron and Steel Holding Group Co.,Ltd.,Rizhao Shandong 276806)

机构地区：[1]日照钢铁控股集团有限公司,山东日照276806

出　　处：《山西冶金》2023年第5期22-25,共4页Shanxi Metallurgy

摘　　要：针对客户在使用Q235B热轧带钢的过程中频繁出现分层开裂的问题,对带钢分层开裂原因进行分析调查,并对开裂试样进行高倍、夹杂物和能谱检测分析,调查厂内工艺执行情况,进行成分控制。结果表明:开裂位置存在带状偏析,且硫化物夹杂含量较高,形成裂纹源,恶化了钢带延展性能,导致在拉伸或折弯过程中开裂。通过控制钢水过热度12~25℃、提升m(Mn)/m(S)≥10、精炼出站w[Ca]≥20×10^(-6)、优化铸坯冷却工艺及轧制工艺等措施,铸坯厚度1/4位置C偏析及Mn S夹杂物聚集得到控制,有效解决了因厚度1/4位置开裂造成的质量异议问题。In response to the frequent occurrence of delamination cracking during the use of Q235B hot rolled strip steel by customers,the causes of delamination cracking in the strip steel were analyzed and investigated.High magnification,inclusion,and energy spectrum detection analysis were conducted on the cracked samples to investigate the process execution in the factory and control the composition.The results indicate that there is banded segregation at the cracking location,and the content of sulfide inclusions is high,forming a crack source that deteriorates the ductility of the steel strip and leads to cracking during stretching or bending.By controlling the superheat of molten steel 12~25℃,increasing m(Mn)/m(S)≥10 and refining outlet w(Ca)≥20×10^(-6),optimizing the billet cooling process and rolling process,C segregation and MnS inclusion accumulation at 1/4 of the slab thickness were controlled,and the quality objections caused by cracking at 1/4 of the slab thickness were effectively resolved.

关 键 词：Q235B 带状偏析 1/4厚度 硫化物 冷弯开裂 

分 类 号：TG142[一般工业技术—材料科学与工程]