超低碳电池壳砂眼缺陷冶金诱因与钢液洁净度的影响研究  

Study on the initiations of pinhole defects in ultra-low-carbon battery shells and the influences of molten steel cleanliness

作　　者：王瑞刚 姜敏[1] 王新华[1] WANG Ruigang;JIANG Min;WANG Xinhua(School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京科技大学冶金与生态工程学院,北京100083

出　　处：《炼钢》2020年第6期49-53,77,共6页Steelmaking

基　　金：中央高校基本科研业务费项目(FRF-TP-18-004B1)。

摘　　要：对超低碳电池壳冷冲压"砂眼"缺陷的冶金原因进行了分析,扫描电镜下发现缺陷部位和周围的钢基体中存在较多Al2O3颗粒,推测"砂眼"为大型Al2O3夹杂物在钢基体冲压变形中破碎所导致。因此,对超低碳电池壳钢的冶炼过程和连铸坯进行了系统取样分析。结果表明,RH精炼过程炉渣改质处理后,渣中w(FeO)=11.12%,而浇铸结束后钢包顶渣w(FeO)=5.85%,说明浇铸中氧化性炉渣对钢液存在持续的二次氧化。相应的,RH精炼结束后钢液静置10 min时,夹杂物数量密度由28.1个/mm2减小至10.5个/mm^2,w(T.O)、w(N)分别由43.4×10^-6、32×10^-6降低至29.6×10^-6、28.5×10^-6;在浇铸前期,中间包内钢水夹杂物数量密度从10.5个/mm^2增加至45.2个/mm^2,w(T.O)、w(N)分别由29.6×10^-6、28.5×10^-6增加至57.8×10^-6、56.1×10^-6,钢中w(Als)降低220×10^-6。热力学计算表明,为减少钢中大型Al2O3,降低电池壳中"砂眼"缺陷发生率,钢包渣中w(FeO)应降低至5%以下。In this study,the metallurgical cause of battery shell pinhole defect during the cold stamping was analyzed and determined firstly.The pinhole defects were detected by ASPEX scanning electron microscopy.A lot of Al2O3 inclusion particles were found in the defect portion.It was considered that the large-size Al2O3 inclusions were broken and resulted in pinhole defects during the cold stamping process.Therefore,a systematic sampling analysis was performed on the smelting process and slab of battery shell steel.The results showed that the mass fraction of FeO in the ladle slag decreased to 11.12% after slag modification during RH refining,and further decreased to 5.85% at the end of the casting,which indicated that the oxidizing slag continuously transferred oxygen to the molten steel during the casting.The number density of inclusions in the molten steel was reduced from 28.1 pcs/mm^2 to 10.5 pcs/mm^2 by holding 10 minutes after RH treatment.The T.O and[N]mass fraction in the molten steel were reduced from 43.4×10^-6 and 32×10^-6 to 29.6×10^-6 and 28.5×10^-6.It was found that the number density of inclusions in the molten steel increased from 10.5 pcs/mm^2 to 45.2 pcs/mm2 at the beginning of casting,and the mass frction of T.O and[N]increased from 29.6×10^-6 and 28.5×10^-6 to 57.8×10^-6 and 56.1×10^-6 respectively,while the[Als]mass fraction in the molten steel reduced by 220×10^-6.It is necessary to improve the slag adjustment effect to reduce the incidence of pinhole defects in the battery shell,and the mass fraction of FeO in the slag should be reduced to less than 5%.

关 键 词：电池壳钢 砂眼缺陷 洁净度 夹杂物 二次氧化 

分 类 号：TF762[冶金工程—钢铁冶金]