Effect of inhomogeneous microstructure on the stress corrosion cracking behavior of 316LN stainless steel weld joint under high-temperature and high-pressure water small punch test.

The stress corrosion cracking (SCC) behavior of 316LN stainless steels (SS) weld joint in high-temperature and high-pressure (HTHP) water were investigated by the newly developed HTHP water small punch test. The results indicated that SCC behavior of weld joint were strongly influenced by the inhomogeneous microstructure. Intergranular fracture dominated the SCC process of heat affected zone (HAZ) and partial hardening was believed to be the main reason for the increased sensitivity of HAZ to SCC. All samples exhibited cleavage fracture characteristics, indicating that film-induced cleavage dominated the SCC process of SS and its welded joints in HTHP water. • The SCC behavior of weld joint were strongly influenced by the inhomogeneous microstructure. • Film-induced cleavage dominated the SCC process of SS and its welded joints. • Partial hardening was believed to be the main reason for the increased sensitivity of HAZ to SCC. [ABSTRACT FROM AUTHOR]