摘要
连铸过程中的点状偏析是后续轧材中带状缺陷的源头,对产品服役过程抗腐蚀性能有重要影响。为了控制管材中的带状缺陷,以C110级石油套管钢为对象,研究了其铸态组织对后续热轧管和调质管中粗大带状缺陷的影响。结果表明,点状偏析主要存在于铸坯中心粗大等轴晶区,其内部存在细小的枝晶结构,但却伴随较严重的斑块状溶质元素偏析,遗传到热轧管中则表现为粗大的带状组织缺陷。这类带状组织很难通过热处理工艺消除,会保留在调质管中,从而影响产品服役性能。浇铸工艺研究表明,当前管坯连铸条件下,控制铸坯中心等轴晶区可有效抑制这类半宏观点状偏析的形成,明显减少热轧管和调质管中的粗大带状缺陷;随着铸坯等轴晶区的缩小,热轧管和调质管壁厚方向的显微硬度均匀性均获得显著提高。
As-cast spot segregation is the origin of banded defects in oil tube products,which will be harmful to the corrosion resistance of the tubes in service.The influence of solidified structure on the large banded defects in hot rolled and QT tubes was studied based on the C110 steel for controlling the banded defects.The results show that the spot segregation exists in the center equiaxed crystal region,which has a fine secondary dendritic structure but with severe speckle like segregation.The spot segregation will be inherited into the hot rolled tubes and appear as wide band defects.Such banded defects are difficult to remove by heat treatment and therefore inherited into the final QT products.Reducing the equiaxed crystal zone in the round castings is beneficial to control the formation and growth of the spot segregation,thereby significantly reducing the large band defects in the hot rolled and QT tubes.The hardness measurement results show that the hardness uniformity of both hot rolled and QT tubes can be obviously improved with the decrease of the as-cast center equiaxed crystal area.
作者
李博
杨飞飞
刘华松
罗明
张忠铧
张家泉
LI Bo;YANG Fei-fei;LIU Hua-song;LUO Ming;ZHANG Zhong-hua;ZHANG Jia-quan(School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China;Tube and Pipe Department,Baosteel Research Institute,Baoshan Iron and Steel Co.,Ltd.,Shanghai 201900,China)
出处
《钢铁》
CAS
CSCD
北大核心
2020年第3期87-95,共9页
Iron and Steel
基金
国家自然科学基金资助项目(U1860111)。
关键词
石油套管
凝固组织
点状偏析
带状缺陷
硬度
oil tube
solidification structure
spot segregation
banded defect
hardness
作者简介
李博(1993-),男,硕士生,E-mail:libo0910@foxmail.com;通讯作者:张家泉(1963-),男,博士,教授,E-mail:jqzhang@metall.ustb.edu.cn。
