Q235连铸板坯角部裂纹形成机理及控制  

Mechanism analysis and control on corner crack for Q235 continuous casting slab

作　　者：周业连 张才贵[1] 江中块[1] 李玉娣[1] 赵建强[1] 左康林[1] ZHOU Yelian;ZHANG Caigui;JIANG Zhongkuai;LI Yudi;ZHAO Jianqiang;ZUO Kanglin(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,江苏南京210039

出　　处：《宝钢技术》2024年第1期66-72,共7页Baosteel Technology

摘　　要：为了解决Q235连铸坯角部裂纹缺陷,采用缺陷微观形貌分析和工艺参数影响规律统计分析相结合的方法研究了缺陷形成原因。结果表明:铸坯矫直前AlN大量析出是其产生角部裂纹的主要原因。基于AlN析出热力学分析,随着钢中铝和氮含量降低,AlN开始析出的温度下降,矫直温度范围内AlN析出量显著减少。考虑实际生产,确定了降铝措施作为改善铸坯角部裂纹缺陷的控制措施,现场应用后,Q235连铸板坯角部裂纹指数由3.59下降到0.19,钢中铝的质量分数平均下降126.64×10^(-4)%,合金使用成本降低。To solve the corner crack of the Q235 continuous casting slab,the cause of the defect formation was studied by combining the analysis of the microstructure of the defect and the statistical analysis of the influence law of the process parameters.The results show that a large amount of AlN precipitation before straightening was the main reason for the occurrence of corner cracks.Based on the thermodynamic analysis of AlN precipitation,with the aluminum content and nitrogen content decreasing,the initial precipitation temperature of AlN decreases,and the amount of AlN precipitation significantly decreases during the straightening temperature range.Based on production control,aluminum reduction measures have been determined as a control measure to improve corner cracks in the casting slab.After the on-site application of aluminum reduction measures,the corner crack index of the Q235 continuous casting slab decreased from 3.59 to 0.19,the mass fraction of the average aluminum in steel decreased by 126.64×10^(-4)%,and the alloy use cost was decreased.

关 键 词：包晶钢 连铸板坯 角部裂纹 氮化铝析出 降铝控制 

分 类 号：TG333[金属学及工艺—金属压力加工]