Environment assisted cracking of 308L weld metal in high temperature water

The environment assisted cracking (EAC) behavior, including stress corrosion cracking (SCC) and corrosion fatigue (CF), of a low carbon 308 L stainless steel weld metal was evaluated in high temperature water. The effects of thermal aging (400 degrees C for 10,0 00 h) on the crack growth rate (CGR) are discussed. Experimental results reveal an environmental acceleration effect on CGRs with decreasing loading frequency, and the environmental enhancement factor reached a value of 50 when the frequency was decreased to 0.00001 Hz. The 308 L weld metal showed excellent SCC resistance regardless of the thermal aging or water chemistry, which is related to the low carbon content and well-controlled duplex microstructure. After thermal aging, the ferrite/austenite (gamma/delta) phase boundaries show negligible sensitization, consistent with the low carbon concentration. No preference of the gamma/delta crack path and no elevated EAC either with thermal aging or in oxidizing water was attributed to the no sensitization of the gamma/delta boundaries before and after thermal aging. (C) 2021 Elsevier B.V. All rights reserved.