Large-Scale Wet Hydrogen Sulfide Cracking Performance: Evaluation of Metallurgical, Mechanical, and Welding Variables

Abstract

The serviceability of welded steel equipment in wet hydrogen sulfide (H2S) service was studied. Large-scale exposure tests were conducted using a steel pressure vessel containing various welded test plates. Effects of variables including steel base plate composition, metallurgical processing, welding, applied stress, and orientation were examined. Particular attention was given to large-scale behavior vs behavior for small-scale laboratory test specimens under an applied tensile stress; performance of conventional carbon steels (CS) vs advanced CS designed for enhanced resistance to hydrogen-induced cracking (HIC); and the interrelationship of stress, welding, and plate orientation on susceptibility to wet H2S cracking. Results provided insight on the role of steel quality and microstructure in susceptibility of CS to HIC, stress-oriented hydrogen-induced cracking (SOHIC), and sulfide stress cracking (SSC).