304L不锈钢连铸坯表面振痕形貌及宏观偏析成因分析  

Formation Mechanism of Macro-segregation and Surface Oscillation Marks in 304L Stainless Steel Continuous Casting Billets

作　　者：马宁博[1] 雷作胜[1] 金小礼[1] 任忠鸣[1] 

机构地区：[1]上海大学材料科学与工程学院,上海市现代冶金与材料制备重点实验室

出　　处：《特种铸造及有色合金》2009年第9期837-841,共5页Special Casting & Nonferrous Alloys

基　　金：国家自然科学基金资助项目(50604010;50874133);长江学者和创新团队发展计划资助项目(IRT0739)

摘　　要：采用金相显微镜、扫描电镜和能谱分析等手段观察分析了304L不锈钢连铸坯表面振痕附近微观组织形貌,发现了一种新的熔断溢流型振痕形貌和两种表面宏观偏析带:一种出现在凹陷型振痕的底部,另一种位于溢流型振痕底部弧钩线上方的三角区域。能谱分析结果显示,主要偏析元素为Si、Mn和Ni,其偏析率分别为1.1～1.6、1.3和1.1～1.2。研究结果表明,熔断溢流型振痕和偏析带的形成与连铸过程中初始凝固区域的温度变化、弯月面的凝固变形以及结晶器的振动有着密切的关系。Microstructure near oscillation marks (OSM) on 304L stainless steel continuous casting billets was observed by optical microscope (OM),SEM (scanning electron microscope) and EDS (energy dispersive spectrometer). A new type of morphology that is fusing-overflow-type OSM and two types of surface segregation in which one occurs at the bottom of the depression-type OSM,and the other occurs at the end of the overflow region above the hook origin line were observed. The EDS results reveal that the main segregation elements are Si,Mn and Ni,and the segregation rates are 1.1~1.6,1.3 and 1.1~1.2,respectively. It is concluded that the formation of fusing-overflow-type OSM and surface segregation are closely related to the temperature variation in initial solidification region,the deformation of solidifying meniscus,and the oscillation of mould.

关 键 词：连铸 不锈钢 初始凝固 振痕 表面偏析 

分 类 号：TF777[冶金工程—钢铁冶金]