Stress Corrosion Cracking of X-70 Steel in Carbonates, Solutions

The aim of this work was to study the effect of different heat treatments on the stress corrosion cracking (SCC) resistance of X-70 pipeline steel in diluted solutions of NaHCO3 (0.1 M, 0.05 M, 0.01 M, and 0.005 M), and in solutions of NaHCO3 with addition of KCl, CaCl2 and MgSO4-7H2O, using the slow strain rate testing (SSRT) technique,and some heat treatments.The results obtained indicated that the quenched and quenched+tempered conditions are the only ones susceptible to HE and the mechanism of SCC in X-70 pipeline steel increased in most diluted solution of NaHCO3 at 50 C, and was dominated by film rupture an anodic dissolution.