Scanning photoelectrochemical analysis of hydrogen permeation on ASTM A516 grade60 steel welded joints in a H2S containing solution

Evaluation of Thiosulfate as a Substitute of Hydrogen Sulfide in Sour Corrosion Fatigue Studies

“…Environmental variables of interest here include the concentration of hydrogen sulfide, salts, pH and temperature. Sour corrosion fatigue tests are usually performed at the free corrosion potential [4][5][6][7][8] in an effort to simulate internal pipeline service conditions. Experimental approaches to study corrosion fatigue include endurance based and crack growth rate based tests, which will be contrasted below.…”

“…A usual way of characterizing corrosion fatigue involves the use of acceleration factors, which is the ratio of crack growth rates in the corrosive environment over that in air. Reported values for acceleration factors for H 2 S saturated seawater range between 20 and 100, depending on K [4,7,8,10]. A typical corrosion fatigue da/dN curve vs. K has three stages.…”

“…Hydrogen sulfide increases corrosion and hydrogen absorption [6], causing embrittlement [7]. Therefore, standards like NACE MR0175 [8] establish limits for use of carbon steels in sour service. For static loads applied on parts designed with conventional elastic design criteria, sulfide stress cracking (SSC) is not a problem for partial pressures of H 2 S lower that 0.3 kPa (0.05 psi) [8].…”

“…At higher partial pressures, SSC-resistant carbon and low alloy steels are required. The aggressiveness of the environment is specified by pH and H 2 S partial pressure [8]. Required composition, heat treatment, hardness and manufacturing procedures are detailed in the standard [8] for the different regimes of pH and H 2 S partial pressure.…”

“…The aggressiveness of the environment is specified by pH and H 2 S partial pressure [8]. Required composition, heat treatment, hardness and manufacturing procedures are detailed in the standard [8] for the different regimes of pH and H 2 S partial pressure. However, with cyclic loads applied at low frequency, SSC-resistant steels can exhibit sour corrosion fatigue even in the regime of pH and partial pressure of H 2 S of SSC immunity [9].…”