37Mn5钢中宏观大尺寸夹杂物形成机理及控制  

Formation mechanism and control of macro large-size inclusions in 37Mn5

作　　者：万文华 李世健 成国光 任振海 徐必靖 苗志奇 WAN Wenhua;LI Shijian;CHENG Guoguang;REN Zhenhai;XU Bijing;MIAO Zhiqi(Zenith Steel Group Co.,Ltd.,Changzhou 213011,Jiangsu,China;State Key Laboratory of Advanced Metallurgy,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]中天钢铁集团有限公司,江苏常州213011 [2]北京科技大学钢铁冶金新技术国家重点实验室,北京100083

出　　处：《江西冶金》2021年第6期1-7,共7页Jiangxi Metallurgy

基　　金：国家自然科学基金资助项目(51374020)。

摘　　要：以EAF-LF-VD-钙处理-CC实际生产工艺路线为背景,利用超声波探伤检测方法,研究37Mn5热轧棒材中毫米级宏观大尺寸夹杂物形貌特征、尺寸大小及成分特点,通过对实际精炼过程中的棒材进行取样分析,探明钢液、炉渣成分和夹杂物的演变规律,同时提出了对应的改进措施。研究结果表明:热轧棒材中造成探伤不合格的宏观大尺寸夹杂物主要由小于10μm细小的CaO-MgO-Al_(2)O_(3)类夹杂物堆集而成,纵截面尺寸长约20 mm,这类夹杂物大都位于高熔点区(非液相区),在连铸过程碰撞、合并、聚集、长大而成。系统的工艺研究表明:这类探伤缺陷形成的主要原因,是电炉出钢和VD真空精炼过程所生成的氧化铝夹杂物没有被有效去除,以及真空后的钙处理工艺没有使其完全低熔点化。控制电炉出钢氧化程度、LF炉氧化铝高效去除以及VD过程较低的铝损失,可显著降低这类探伤缺陷的发生率,并在生产实践中得到了成功应用。Based on the EAF(Electric Arc Furnace)-LF(Ladle Furnace)-VD(Vacuum Degassing)-Calcium treatment-CC(Continuous casting)process of actual production,the morphology,size and composition characteristics of macro large-size inclusions found in 37Mn5 hot-rolled bar by ultrasonic test were studied.The slag and liquid steel were sampled systematically during the actual refining process and their compositions were detected.The evolution of inclusions was studied and the corresponding improvement measures were put forward.The results indicate that the macro inclusions in the hot-rolled bar which lead to unacceptable ultrasonic test results are composed of a large number of CaO-MgO-Al_(2)O_(3) inclusions with size less than 10μm and is about 20 mm long in longitudinal section.Most of these inclusions are located in the high melting point region(non-liquid region)and formed by collision,coalescence,aggregation and growth during continuous casting.The systematic process research shows that the main reasons for the formation of such defects are that the alumina inclusions generated in the process of EAF tapping and VD are not removed effectively,and the calcium treatment process after vacuum does not change alumina inclusions into completely low melting point inclusions.The effective ways to solve this kind of defect problem are to reduce the degree of over-oxidation in EAF tapping,to remove alumina efficiently in LF,to reduce aluminum loss during vacuum degassing,which have been successfully applied in practice.The occurrence frequency of large-size inclusions leading to unacceptable ultrasonic test results is significantly reduced.

关 键 词：37Mn5 钢液精炼 夹杂物 钙处理 洁净度 

分 类 号：TF769[冶金工程—钢铁冶金] TG142[一般工业技术—材料科学与工程]