Premium
SCC of X‐52 and X‐60 weldements in diluted NaHCO 3 solutions with chloride and sulfate ions
Author(s) -
GonzalezRodriguez J.G.,
EspinosaMedina M.A.,
AngelesChavez C.,
ZeferinoRodriguez T.
Publication year - 2007
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.200604047
Subject(s) - stress corrosion cracking , chloride , sulfate , corrosion , bicarbonate , dissolution , hydrogen , sodium sulfate , ion , chemistry , inorganic chemistry , sodium , nuclear chemistry , materials science , metallurgy , organic chemistry
Stress corrosion cracking tests were performed in both X‐52 and X‐60 weldments in sodium bicarbonate (NaHCO 3 ) solutions at 50°C using the Slow Strain Rate Testing (SSRT) technique. Solution concentrations varied between 0.1 to 0.0001 M, and to simulate the NS‐4 solution, chloride (Cl − ) and/or sulfate ( $\rm SO_{4}^{2-}$ ) ions were added to the 0.01 M solution. Tests were complemented with hydrogen permeation measurements and polarization curves. It was found that the corrosion rate, taken as the corrosion current, I corr , was maximum in 0.01 M NaHCO 3 and with additions of $\rm SO_{4}^{2-}$ ions. Higher or lower solution concentrations or additions of Cl − alone decreased the corrosion rate of the weldment. The SSC susceptibility, measured as the percentage reduction in area, was maximum in 0.01M NaHCO 3 . Higher or lower solution concentrations of additions of Cl − or $\rm SO_{4}^{2-}$ decreased the SCC susceptibility of the weldment. The amount of hydrogen uptake for the weldment was also highest in 0.01 M NaHCO 3 solution, but it was minimum with the addition of Cl − or $\rm SO_{4}^{2-}$ ions. Thus, the most likely mechanism for the cracking susceptibility of X‐52 and X‐60 weldments in diluted NaHCO 3 solutions seems to be hydrogen‐assisted anodic dissolution.