Effects of natural gas impurities on hydrogen embrittlement susceptibility and hydrogen permeation of X52 pipeline steel

The influences of CO/CO2 on the hydrogen embrittlement of X52 steel are investigated by a combination of SSRT tests, fracture morphology analysis, TDS tests, gaseous hydrogen permeation tests. CO/CO2 inhibits hydrogen embrittlement, the inhibitory effect increases with the CO/ CO2 partial pressure, and CO shows a stronger inhibitory effect. TDS and hydrogen permeation tests show that the inhibition is due to the decreases in the subsurface hydrogen concentration and inner hydrogen content. Secondary permeation tests indicate that the adsorption of CO on the steel surface is stronger and more stable, which leads to its stronger inhibitory effect.