摘要
翘皮缺陷是热轧Q235B带钢常见的典型表面缺陷之一,具有分布无规律性且深度较浅等特征,严重影响热轧带钢产品的表面质量.采用金相显微镜、扫描电镜和能谱仪相结合的方法对热轧Q235B带钢翘皮缺陷成因进行了研究分析,并提出了改进措施.结果表明,产生翘皮缺陷的主要原因包括钢坯表面产生裂纹,裂纹处氧化铁皮未除净,Si及Mn的二次氧化物与氧化铁皮在后续轧制过程中被带入钢板表面,部分结晶器卷渣进入铸坯表面.通过采取保护浇铸、优化浸入式水口插入深度、稳定拉坯速度及控制轧制过程中高压除鳞时的表面洁净等措施,可有效降低翘皮缺陷发生率.
Abstract
The warping defect is one of the typical surface defects of hot-rolled Q235B steel strip,which has the characteristics of irregular distribution and shallow depth,and seriously affects the surface quality of hot-rolled steel strip products.In this paper,the causes of warping defects in hot-rolled Q235B steel strip were analyzed by using a combination of metallographic microscope,scanning electron microscope,and energy spectrometer,and improvement measures were proposed.The results showed that the main causes of warping defects were the formation of cracks on the surface of the steel billet,the failure to remove the iron oxide scale completely at the cracks,the introduction of secondary oxides of Si and Mn and iron oxide scale into the steel plate surface during subsequent rolling processes,and the entry of some slag from the crystallizer into the surface of the cast billet,resulting in warping defects.By adopting protective casting,optimizing the insertion depth of submerged nozzle,stabilizing the casting speed,and controlling the surface cleanliness during high-pressure descaling during rolling process,the incidence of warping defects can be effectively reduced.
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