Stress Corrosion Cracking in 18% Ni (250) Maraging Steel

The susceptibility of 18% Ni (250) maraging steel to stress corrosion cracking in 3.5% NaCl solution has been investigated. Metallographic and fractographic examinations show distinct differences between specimens broken under free corrosion conditions and those broken under hydrogen charging conditions. It is proposed that stress corrosion cracking occurs by anodic path dissolution at potentials more noble than about -600 mV (SCE), that hydrogen embrittlement cracking occurs at potentials more active than about -800 mV, and that a mixture of anodic path dissolution and hydrogen embrittlement cracking occurs in the intervening potential range of -600 mV to -800 mV. Stress corrosion cracking in freely corroding maraging steel (potential ≈-580 mV) is thought to occur by anodic path dissolution.