连铸板坯中心裂纹对钢板分层形成的影响

Influence of Continuous Casting Slab Center Crack on Forming Lamination Plate

对断面中心有裂纹缺陷的铸坯进行了探测和解剖分析,并对轧制后钢板进行探伤,依照探伤图谱,选择分层缺陷明显的部位,用扫描电镜等对其金相组织、缺陷形态和微区成分进行分析,得出分层部位的缺陷组织主要为沿轧向分布的铁素体带,在其内部沿轧向分布有条状或片状硫化物,是中厚板分层产生的主要原因。通过分析得出轧制时铸坯内部焊合及修复的边界条件:硫化物尺寸控制在5μm以下,硫含量降低到0.02%以下。

The casting slabs which there are cracks on their section center were detected and anatomized,then the plates which the casting slabs were rolled were probed,according to the micrograph,the parts which have obvious delaminating defect were analyzed to their metallographic phase organization,detects morphology and compositions in micro area with scanning electron microscopy.It is conclusion that the cause of delaminating of medium plate is the detect organization of delaminating position being mostly ferrite strip along rolled direction,in which there are some strip or flaky sulfides.At the same time the boundary conditions seamed and mended of continuous cast slab were educed.Control size of sulfide is below 5 μm,sulfur content is less than 0.02%.