利用光学显微镜、扫描电镜及能谱仪对Q345B钢板拉伸性能不合格的原因进行了分析。结果表明: 试样中心的白点缺陷、微裂纹和硫化物夹杂, 是引起该批次Q345B钢板拉伸性能不合格的主要原因; 偏析带上的魏氏组织也会对钢板的延伸性能产生不利影响。最后针对钢板拉伸性能不合格原因提出了工艺改进措施。

By using optical microscope, scanning electron microscope and energy dispersive spectrometer, the tensile properties disqualification reasons of Q345B steel plates were analyzed. The results show that the existence of a large number of flake defects, tiny cracks and sulfide inclusions at the center segregation band, was main reason for the disqualification of tensile properties of Q345B steel plates. At the same time, the Widmanstatten structure also had a negative impact on the extension of the steel plates. Finally, according to the disqualification reasons, improvement measures were put forward.