The crack growth rate, C, for Type 304 stainless steel was measured in-situ in 1N H2SO4+0.5M NaCl solution at 25°C, 40°C and 80°C. In this electrolyte, the steel suffers SCC even at lower temperatures than the critical temperature for SCC in neutral chloride solutions, Tc, thus allowing C to be measured at the lower temperatures. At more noble potentials, the observed cracking rate, Cob, was found to exhibit electrode potential dependency it was found that this measured Cob was equal to the dissolution rate measured via the polarization curve measurement. The crack growth rate, C, of SCC was determined at less noble potentials where Cob remained independent of potential. This rate was found to be equal to the rate measured in the neutral chloride solutions and is therefore applicable for use as the crack growth rate in the competition concept which states that SCC will not occur when dissolution rate excesses cracking rate. Based on the competition concept, the estimated Tc for Type 304 steel was 40°C which was nearly equal to 50°C measured in the previous work.
Keywords stress corrosion cracking, stainless steel, cracking rate, dissolution rate, critical temperature