某预应力混凝土用钢棒在静置过程中发生了延迟断裂,采用宏观观察、化学成分分析、硬度测试、扫描电镜和能谱分析、金相检验等方法对其断裂原因进行分析,结果表明:预应力混凝土用钢棒断裂的主要原因为30MnSi材料表面存在结疤及微裂纹等缺陷,这些缺陷为氢致延迟断裂提供了条件。

The delayed fracture of a prestressed concrete steel bar occurred in the process of standing. The fracture reasons were analyzed by means of macroscopic observation, chemical composition analysis, hardness test, scanning electron microscopy and energy spectrum analysis, metallographic examination and other methods. The results show that the main reason for the fracture of the steel bar for prestressed concrete was the scarring and micro-cracks on the surface of 30MnSi material. These defects provided conditions for hydrogen-induced delayed fracture.