Stress corrosion cracking of stainless steel used in drill collars

The present work, studies the stress corrosion cracking behavior in austenitic Fe-Cr-Mn-N stainless steel, in as received, solubilized and sensitized conditions, submitted to several chlorides environments. To evaluate the stress corrosion cracking susceptibility, double cantilever beam specimens, fatigue precracked, side grooved and wedge loaded were used. The environments employed were boiling solution of 45wt.% of MgCl2 at 154 deg. C and synthetic marine environment at ambient and boiling temperature. The susceptibility to stress corrosion cracking has been evaluated in terms of the corrosion stress intensity limit factor, KISCC, applying the fracture-mechanics concept. The results showed that only the specimens in the as received and sensitized conditions, were susceptible to the stress corrosion cracking effect in the boiling solution of 45wt.% of MgCl2 at 154 deg. C, and mean values of the stress corrosion intensity limit factor, KISCC, of 15MPam and 7.8MPam, respectively