Hydrogen assisted cracking in progressively drawn pearlitic steel

This paper analyses the hydrogen assisted cracking (HAC) behaviour of cold drawn prestressing steels with different degrees of cold drawing. The experimental results showed a progressively anisotropic behaviour as the degree of cold drawing increases, with an evolution in the fracture behaviour from mode I (isotropic behaviour in slightly drawn steels) to mixed mode propagation (strongly anisotropic behaviour in heavily drawn steels). The fractographic analysis revealed changes in the microscopic topography depending on the fracture propagation mode, with evolution from pure tearing topography surface (TTS) in slightly drawn steels to a kind of very deformed TTS in heavily drawn steels.