Relationship of Microstructure and Stress Corrosion Cracking of Type 410 Stainless Steel

Three heats of AISI Type 410 stainless steel that exhibited different degrees of susceptibility to stress corrosion fracture in pure-water environments were investigated by electron microscopy and diffraction techniques to correlate microstructure with stress corrosion fracture behavior. In the hardened condition and tempered at 650 F, these steels cracked at stresses as low as 40,000 psi along networks of essentially untempered martensite in the prior austenite grain boundaries. Tempering at a temperature (1175 F) high enough to break up the continuous network in the prior austenite grain boundaries reduced stress corrosion susceptibility, but at the expense of a reduction in tensile properties. 3.2.2