A study on the susceptibility to stress corrosion cracking (SCC) of API X-80 pipeline steel in simulated fuel grade ethanol has been carried out by using slow atrain rate tests, polarization curves and noise in current measurements. Environmental factors included water (0, 1, 5, 10 and 20 vol.%) and chloride content (0, 10 and 32 g/L), whereas heat treatment included water quenched, quenched and tempered, oil quenched and water sprayed. Additionally some tests were carried out in absence of oxygen. Results have shown that X-80 carbon steel in the as-received condition was susceptible only when 5% water and 10 g/L of NaCl were present. Heat treatments suppressed this susceptibility. Conditions that increased the corrosion rate also increased the SCC susceptibility, which, together with metallographic observations and noise in current measurements, indicated that SCC in this environment is caused by a film rupture, dissolution mechanism.
Keywords: Electrochemical Tests Stress; Corrosion Cracking; Bioethanol;