Hydrogen embrittlement and rock bolt stress corrosion cracking

This paper considers our recent research on rock bolt stress corrosion cracking (SCC) which studied the influence of metallurgy using a range of (1) existing rock bolt steels and (2) commercial steels. The chemical composition, mechanical properties and microstructures of these steels varied considerably. The aim is to understand this failure mechanism and in particular to apply the knowledge gained from the study of SCC and hydrogen embrittlement (HE) of steels. The resistance of 1008, X65, X70 and 4145H to SCC/HE was similar, an effect which could be hardly expected as these steels have different strengths, microstructures and H-trap distributions. Different steel microstructures (pearlitic–ferritic and tempered martensite) had similar resistance to SCC and HE in the most aggressive conditions (pH 2.1 and −1500 mVSCE) and had the same dimple rupture fracture surface.