末端电磁搅拌对连铸坯低倍及微观组织的影响.pdfVIP

末端电磁搅拌对连铸坯低倍及微观组织的影响1 张志远 曾朝晖 宁 玫 芦居桂 孙梅红 杨翠丽 卢 弘 （天津钢管集团股份有限公司技术中心，天津 300301 ） 摘 要 未开启和开启末端电磁搅拌（F-EMS ）微合金化钢连铸坯低倍试验结果表明，未采用末端 EMS 铸坯柱 状晶区较发达且占比例较大；开启末端 EMS，铸坯芯部有大面积弥散分布的中心疏松，柱状晶部分被打碎，在铸 坯约二分之一半径处有一明显的白亮偏析带。原位分析试验表明，白亮偏析带主要为 C、Mn 、Nb 、Mo 、V 、Cr 等元素的负偏析。铸坯芯部有沿晶微裂纹及成分偏析，成分偏析区碳氮化物呈网状析出，晶界处有由于选分结晶 而形成的块状硫化物夹杂。铸坯球形夹杂物分布与成分偏析无关。连铸坯内弧侧高 Mo 含量区域组织细小，并有 明显的弥散分布的微区成分偏析，而基体部位铸坯贝氏体条束较粗大。微区成分偏析区 Mo、C 含量明显高于基 体部位。 关键词 电磁搅拌 连铸 偏析 碳氮化物 Effect of F-EMS Billet on Macroscopic and Microstructure Zhang Zhiyuan Zeng Zhaohui Ning Mei Lu Jugui Sun Meihong Yang Cuili Lu Hong (Tianjin Pipe (Group) Corporation Technology Center, Tianjin, 300301) Abstract In this paper, the macroscopic test on the No F-EMS and F-EMS micro-alloy steel billet, the results reveal that it has obviously columnar crystal of the billet which no F-EMS treatment. Through EMS treatment, it has large quantity disperse center porosity, some of the columnar crystal has been break. There is a segregated band on one-half radius of the steel billet. The original position analysis of the segregation band results indicate that several elements has segregation, including C，Mn，Nb ，Mo ，V and Cr. There are some micro-crack and segregation in the billet central, and sulfide at grain boundary and some carbonitride along the intergranular. The distribution of the spherical inclusion at random, which has no relative with the chemical segregation. In the higher Mo area of the inner arc billet, there has a finer microstructure and also has micro segregation. However, it has coarse bainite microstructure on the matrix. Compare to the matrix of the billet, Mo and C contents are higher of the micro-segregation area. Key words EMS, CCM, segregation, carbonitride 1 引言 随着市场竞