Effect of Heat Treatment on the Stress Corrosion Cracking Susceptibility of a Dual-Phase Steel

The stress corrosion cracking (SCC) susceptibility of a microalloyed steel under different heat treatments in 3.5% sodium chloride (NaCl) solution with different pH values (3, 7, and 12) using the slow strain rate testing (SSRT) technique has been evaluated. Heat treatments include the as-received condition (with a martensitic/perlitic microstructure), a quenched from 750°C condition (producing a dual-phase microstructure consisting of martensite/ferrite), and a quenched from 950°C condition (producing an almost pure martensitic microstructure). The as-received and quenched from 950°C conditions were highly susceptible to SCC whereas the steel with the dual-phase microstructure was only mildly susceptible. A direct correlationship was found between the corrosion rate and the SCC susceptibility. The SCC mechanism seems to be hydrogen embrittlement.