低碳钢板表面发裂缺陷分析

针对本钢BG490CL热轧钢板和St02Z镀锌板在生产过程中多次出现的表面发裂缺陷问题，利用光学显微镜和扫描电镜等物理设备对缺陷部位的宏观特征、微观形貌的不同角度的详细观察，以及对金相组织、高倍扫描、夹杂物和冶金质量变化等方面进行了全面的检验分析。最终得出结论，发裂缺陷是由于板坯连铸时产生的较深沟形振痕残余造成，避免方法是合理确定浇铸时钢的液面波动。

Analysis on hairline crack defects on surface of low carbon steel plate

Aiming at the surface hairline crack defects often occurred in the production of the hot rolling plate BG490CL and galvanized steel sheet St02Z in Benxi Iron and Steel (Group) Co., Ltd. The metallographic structure, high scanning, variation of the inclusions and metallurgical quality were comprehensively detected and analyzed by using the physical equipment such as microscope and SEM and observing the macro characteristics and the microstructure of defects from different angles in detail. Eventually, it concluded that the hairline crack was induced by the remained deep vibration mark of casting slab, which can be avoided by determining the reasonable liquid level fluctuation of the steel in casting.