Q345A(厚)钢板表面微裂纹产生原因分析  

Analysis of surface micro-crack on thick plate of Q345A

作　　者：杨浩 陈文满 何宇明 潘时松 潘咏忠 苏刚 

机构地区：[1]重庆钢铁股份有限公司总工程师办公室,重庆401258

出　　处：《钢铁》2015年第8期39-44,共6页Iron and Steel

摘　　要：钢板表面微裂纹严重影响产品质量。通过微裂纹特征分析、观察铸坯和钢板金相及能谱(EDS)检测、梳理生产过程参数,得出Q345A(厚)钢板表面微裂纹产生的主要原因是连铸结晶器铜板镀层脱落。这一方面会导致铜渗透入坯壳的奥氏体晶界,产生晶界裂纹;另一方面会因热应力不均而产生裂纹,并在含钛等裂纹敏感性强的钢中表现尤其明显。控制措施为:提高结晶器铜板质量,杜绝露铜;加强生产前对镀层铜板和生产后铸坯质量的检查;通过做好保护浇注等措施,提高钢水洁净度。Surface micro-crack on plate seriously deteriorates the product quality. After metallographic observ ation and EDS teste on slab and plate,the characteristics of the micro-crack and production parameters analyzed,the reason producing surface micro-crack on thick plate Q345 A was that the falling coating of mold copper plate. For one hand,this situation caused copper element to infiltrate into the austenite grain boundary through slab surface which makes the crack along the grain boundary easy to happen. For the other hand,crack was also generated by thermal stress disproportionation after coating exfoliated,and the crack was more serious on slab containing Ti,which is sensitive to crack. Therefore,some control measurements were proposed. Firstly,the quality of mold copper plate is needed to be improved and avoiding copper wall be exposed. Secondly,the inspection of mold copper plate is enhanced before production and same measurements for the surface quality of slab after production. Finally,the protective casting is proposed to improve the steel cleanliness.

关 键 词：板坯 表面微裂纹 结晶器铜板露铜 二次氧化 

分 类 号：TG142.15[一般工业技术—材料科学与工程]