中厚钢板分层缺陷的形成机制分析

为降低中厚钢板产生分层缺陷的几率、提高控轧控冷钢材的质量性能,对试验的中厚钢板进行无损探伤,依照探伤图谱选择分层缺陷严重的部位,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.结果表明,分层部位的缺陷组织主要为沿轧向分布的铁素体带中条状或片状硫化物是中厚板分层产生的主要原因.当钢中的含硫质量分数降低到0.02%以下、硫化物临界尺寸小于5μm时,可有效防止分层缺陷产生.

Analysis of Forming Mechanism of Lamination Defect of Steel Plate

To reduce the probability of lamination defect formed during plate steel rolling and improve its quality and mechanical properties specimens of the cold rolled steel plates were nondestructively detected. Then, according to the positions of severe lamination defect found from spectural patterns as the result of detection, the defect, morphologies and compositions of the specimens were analyzed by SEM, etc.. The results showed that the microstructure of lamination defects formed in steel plates are mainly the component of strip/plate sulfides in ferrite bandings distributed along the rolling direction, which is typically the reason why the lamination defects formed. It was concluded that lamination defects can be prevented efficiently if the sulfur content in steel is reduced to below 0.02% and the critical size of sulfides is less than 5 μm.