Q345B�����ִ�������ѳ��򼰽������

 通过对比分析Q345B热轧钢带冷弯断裂试样和合格试样的力学性能、金相组织、微观夹杂物数据及对应连铸板坯试样的化学成分和低倍检验数据，并借助扫描电镜及能谱分析异进行断口分析，得出连铸板坯横截面1/4～1/5位置中间裂纹是造成此次钢带冷弯断裂的主要原因，并提出了通过优化连铸工艺、增加电磁搅拌等措施有效控制铸坯中间裂纹的形成，从而解决Q345B热轧钢带冷弯断裂问题的方法，取得了显著效果。

Reasons and Solutions of Cold Bending Fracture of Q345B Hot-Rolled Strip

Through comparative analysis on mechanical properties,microstructure,microscopic inclusions and che-mical compositiom and macro-inspection data of cold bending fracture sample of Q345B hot-strip and eligible sample with scanning electron microscope（SEM） and energy spectrum.The results shows that crack at 1/4-1/5 position in center of casting slab cross section is the main reason for cold bending fracture.And,by optimizing continuous cas-ting process to effectively control formation of crack in the slab.Significant result has been achieved to solve Q345B cold bending fracture.