An experimental study on the effects of loading mode and hydrogen charging sequence on the hydrogen-assisted cracking (HAC) of quenched and tempered AISI 4135 steel were conducted to determine the mechanism of hydrogen embrittlement (HE). The cracking susceptibility and fracture mode were greatly affected by the loading mode and hydrogen charging sequence. Although the results revealed a complicated dependence on the testing condition, most phenomena could be explained by (1) the increase in hydrogen concentration resulting from the interaction of hydrogen with shear stresses and (2) the crack-opening normal stress acting on a plane with a high hydrogen concentration. Hydrogen transport by dislocation and embrittlement by decohesion are also invoked to explain the observations. A discussion aimed at elaborating the mechanism of stress corrosion cracking (SCC) for a given metal/ environment system by the loading mode effect is included.

Subject
Dislocation, Hydrogen concentration, Notches, Fracture surfaces, Stress cracking, Hydrogen charging, Mechanical properties, Stress, Tensile stress, Fracture, Grain boundary, Stress corrosion cracking, Hydrogen
National Association of Corrosion Engineers
1986
You do not currently have access to this content.