Evaluation of environment-assisted cracking susceptibility of a grade X100 pipeline steel

摘要

Susceptibility of as-received grade X100 steel was compared to that of simulated and seam-weld heat-affected zone microstructures by slow strain rate testing in a sodium hydrogen carbonate-sodium carbonate solution at 75 ℃ over a potential range of -500 to -1100 mV vs. standard calomel electrode (sce). Heat treatment has an effect on the resistance of the steel to environment-assisted cracking. Stress corrosion cracking at anodic potentials was intergranular (IG) and became transgranular (TG) as the free corrosion potential of -890 mV (sce) was approached. At cathodic potentials, transgranular hydrogen embrittlement occurred with faster growth rates up to 1.4 ℃ 10~(-5) mm/s and less secondary cracking.