The role of carbon level on the stress corrosion cracking characteristics of steel

Abstract

The present study examined the interrelated effects of bulk carbon level, 0.4% to 0.8%, and yield strength on the threshold stress intensity value, K ISCC , of steels in a sea water environment. Significant effects of these parameters on K ISCC were demonstrated. At constant yield strength, the true effect of carbon level was evident, viz., with increasing C level up to 0.4% K ISCC values were dramatically reduced. Above this value, however, K ISCC values again increased up to 0.8% C. This trough in the K ISCC -% C relationship was tentatively explained in terms of microstructural changes. A review of the various SCC models in hydrogen producing environments illustrated that the Nair - Tien approach exhibited excellent commonality with the present data and reported data in the literature. Finally, abrupt changes in the SCC failure mode were evident in the 0.4% steel. Such failure mode changes were readily explained in terms of Hydrogen Assisted Cracking model for SCC phenomena.