Аналіз впливу комбінації стрес-корозійних чинників на корозійне розтріскування від напруження трубної сталі при рН, близьких до нейтральних

Abstract

Corrosion-mechanical properties of pipe steel Х70 in model soil electrolyte (MSE) under influence of different combination of factors were investigated. It was established that factors which led to stress-corrosion cracking (SCC), are corrosion environment, applied loads (stretching and cyclic) and cathodic potential. The presence of local corrosion defect (LCD) and variable moistening may promote in some extent SCC process. For example, under variable moistening by MSE at corrosion potential the pipe steel specimens with accumulated cyclic stress and LCD demonstrate the inclination to SCC, which don’t not occur at full immersion. At applied cathodic potential -1,0 V both at full immersion and at variable moistening pipe steel specimens in the initial state, with accumulated cycle stress without LCD and with accumulated cycle stress and LCD show the inclination to SCC. It should be noted that inclination to SCC of pipe steel with accumulated cyclic stress and in the presence of LCD is practically identical both at full immersion and at variable moistening, that indicate on prevail influence of cathode potential and LCD over variable moistening.