针对我公司生产的Z向钢板出现超声波探伤不合，通过低倍、金相、裂纹分析、Z向拉伸及扫描电镜等检验，分析探讨了缺陷产生的原因及机理。结果表明钢板中心裂纹为白点缺陷，钢中氢含量高是造成钢板探伤不合的主要原因。目前通过采取有效的措施，减少了钢板白点缺陷的产生，使Z向钢板探伤合格率提高到97%以上。

The causes and the mechanism of ultrasonic test defects in Z-direction steel plate in ShouGang were investigated by means of macroscopic test, metallographic inspection, crack analysis, Z-direction tensile and electron microscopy, ect. The results show that central crack in the defect plate is flake and high hydrogen content induces the ultrasonic test defects. Thereby the valid measures have been taken to reduce the flake defects and percent of ultrasonic test pass is up to 97%.