Hydrogen-induced Cracking Behavior of Bainite Pipeline Steel

NACE TM2048-2005 standard was used to test the hydrogen induced cracking sensitivity of hot rolled X120 pipeline steel.The crack morphology and microstructure were observed with optical microscopy(OM),scanning electron microscopy(SEM) and transmission electron microscopy(TEM).The hydrogen induced cracking behavior of the bainite pipeline steel was discussed based on the hydrogen pressure theory.The results showed that the cracks mainly nucleated from the large size inclusions.The type of crack propagation was intergranular along the prior austenitic grain boundaries.The lath bainite microstructure had good hydrogen induced cracking resistance.