Engineering Critical Assessment of nickel-based clad pipeline girth welds in a wet H2S-containing environment

Abstract

Specimens from nickel-based clad pipeline girth welds were tested in H2S solution. The results of the fatigue crack growth rate curve at higher ΔK values were about 4 times higher than the in-air values. The rate at 180°C was generally higher than the in-air data for flaw assessments found in the British Standard BS7910 by a factor of up to 3 times. From the analyses of the diffusible hydrogen, the backing steel of such pipelines are predominantly protected from the sour environment by the corrosion-resistant alloy clad layer. The results from this study are relevant for desktop Engineering Critical Assessment of girth welds of such pipelines.