某批次Q345E钢在进行低温冲击试验时，发现其低温冲击性能不满足标准要求。采用扫描电镜分析、夹杂物评定、金相检验、晶粒度评定等方法，分析了其冲击性能不合格的原因。结果表明：钢材中的硫化物在心部偏聚，夹杂物的存在导致基体连续性被破坏，当受到冲击作用力时，钢材的有效受力面积和冲击吸收面积变小，裂纹在该处萌生并快速扩展；钢材的晶粒尺寸较大，使金属间的结合力变小，最终导致该钢材的低温冲击性能不合格。

During low temperature impact testing of a batch of Q345E steel, it was found that its low temperature impact performance did not meet the standard requirements. The causes of unqualified impact properties were analyzed by means of scanning electron microscope analysis, inclusion evaluation, metallographic examination and grain size grading. The results show that the sulfide in steel concentrated at the center, and the presence of inclusions led to the destruction of the continuity of the matrix. When subjected to impact forces, the effective stress bearing area and impact absorbing area of the steel became smaller, where cracks initiated and rapidly expand. The large grain size of steel reduced the bonding force between metals, ultimately leading to unqualified impact performance of the steel.