EFFECT OF CARBON SEGREGATION AT GRAIN BOUNDARY ON INTERGRANULAR STRESS CORROSION CRACKING OF CARBON STEEL IN “ETHANOLAMINE + CO2” ENVIRONMENT

ABSTRACT The effect of carbon segregation at grain boundary on the susceptibility to intergranular stress corrosion cracking of 0.1 carbon steel in the environment of 15% ethanolamine aqueous solution aerated with CO 2 gas at 100° C has been studied by slow strain rate tests of = 6.4 × 10 −6 s −1 at a constant controlled polarization potential of −0.65 V(s.c.e.). The concentration of carbon segregation at grain boundary was changed by normalization heat treatment and was detected by scanning electron probe. The results show that the dependence of susceptibility to intergranular stress corrosion cracking for the 0.1 carbon steel upon normalization temperatures is similar to that of relative concentration of carbon segregation at grain boundary. Therefore, the conclusion is drawn that intergranular stress corrosion cracking of 0.1 carbon steel in the “ethanolamine + CO 2 ” environment is related to carbon impurity segregation at grain boundary.