Effect of electrolyte composition on crack growth rate in pipeline steel

Effect of temperature on the crack growth in pipe steel X70 in a weakly acidic electrolyte

“…The stress intensity factor at the crack tip K (MPa·m 0.5 ) was carried out according to [15][16][17]. The initial value, K = 45 MPa·m 0.5 , was chosen on the plateau of the kinetic curve of X70 steel fracture curve, i.e., under the conditions where the crack growth rate nearly does not depend on K [14,17].…”

“…Moreover, the assumption on the synergistic effect of local metal dissolution and hydrogen absorption was often made [1]. It has been shown that the nature of the predominant mechanism of pH-neutral SCC of pipe steel X70 depends on the cyclic mechanical strain mode and on the electrode potential [14][15][16][17]. In fact, local dissolution of the metal is the predominant mechanism of SCC at relatively small amplitudes of cyclic strain variation and at the steel corrosion potentials in NS4 solution (pH 6.8).…”

“…In a weakly acidic buffer electrolyte with pH = 5.5 (i.e., at the threshold of the solution acidity corresponding to type II SCC), the crack growth occurs not only under cyclic strain by also under constant tensile stress. It was established that local metal dissolution is the predominant mechanism of transgranular crack growth [14][15][16][17][18]. Apparently, SCC in a weakly acidic buffer electrolyte is a special case of transgranular SCC of pipe steels and may demonstrate a number of specific features.…”

Modification of bituminous coatings to prevent stress corrosion cracking of carbon steel

“…In view of this, development of an efficient SCC inhibitor is a task of current interest. It is known that SCC in major and field gas pipelines occurs by the local anodic dissolution mechanism [3]. Therefore, the CI should be of passivating type and should form nanosized passivating surface layers that suppress electrochemical processes on pipe steel surface.…”

Peculiarities of corrosion degradation of steel of oil pipelines

“…The problems of corrosion and corrosion fatigue of pipeline steels are dealt with in the works of A. Marshakova [13] and P. Marcus [14], where physical, chemical and electrochemical fundamentals associated with this problem are provided. G. Nykyforchyn [15] and co-workers proposed a method for evaluating the operational degradation of materials of conduits operated on continuous bases.…”