宽厚板连铸坯中间裂纹成因分析及控制

针对某钢厂100t转炉→LF钢包精炼炉→板坯连铸机工艺流程和生产试验数据,探讨了板坯连铸一种内外弧型中间裂纹的发生机制。结果表明,连铸坯鼓肚收缩应变是中间裂纹产生的外因,钢的化学成分决定其高温力学性能,是中间裂纹产生的内因。某钢厂连铸板坯中间裂纹的产生是连铸坯鼓肚收缩应变和钢种的高温力学性能共同作用的结果,而弯曲矫直应变是中间裂纹扩展的重要影响因素,可能导致中间裂纹的扩展。结合钢种和铸坯规格的合理辊缝设计对控制中间裂纹至关重要。

Cause analysis and control of intermediate crack in wide and heavy plate continuous castiong slab

The occurrence mechanism of intermediate crack in slab was discussed on the basis of the experiment data of 100 t ConverterLFCC production line. The results showed that the bulging strain and roller gap shrinking strain were the outer causes of the intermediate crack. The high temperature mechanical property of steel was determined by its chemical component, which caused the intermediate crack. The intermediate crack was the interaction of bulging strain and roller gap shrinking strain and the high temperature mechanical property of steel. And the bending strain and straightening strain had very important effect on the propagation of intermediate crack in CC slab, which may cause the extension of intermediate crack. Reasonable roller gap design combined with the steel grade and specification was very important for the control of the intermediate crack in slab.