Abstract:

In this paper, the stress corrosion cracking （SCC） characteristics of GC-4（40CrMnSiMoVA） ultrahigh strength steel is investigated using the slow strain rate technique. The results of three differently heat-treated specimens show that GC-4 steel is sensitive to SCC in both 3 % NaCl solution and distilled water. The strength, percentage elongation and fracture energy of the material are greatly reduced in the presence of corrosive media. Moreover both anodic and cathodic polarization can promote SCC behavior further. It is shown that both hydrogen assisted cracking and anodic dissolution are important factors of SCC of GC-4 steel in 3 % NaCl solution.

Key words: stress corrosion cracking, slow strain rate technique, electrode potential