Effect of Long-Term Operation of Gas Pipeline on Stress-Corrosion Cracking under Cathodic Polarization

Keywords

stress-corrosion cracking, pH, hydrogen embrittlement, steel, fracture

Abstract

Stress-corrosion cracking (SCC) of the base metal from the linear section of a main gas pipeline after 40 years of operation was investigated in near-neutral pH solution NS4. It was established that at potentials more positive than -1.050 V, SCC of unexploited pipe specimens occurs primarily through the hydrogen embrittlement (HE) mechanism. For the pipe after 40 years of service, SCC develops via mixed mechanism – anodic dissolution (AD) and HE with dominant the last one. Under these conditions, amount of hydrogen permeating into steel is approximately the same for both the unexploited and the operated pipe – 0.0296 and 0.0241 mol/dm³, respectively.

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