The Effect of Microstructure on Stress Corrosion CrackingGrowth Rates of LowAlloy High Strength Steel Welded Joint

Abstract

The correlation of multi-microstructure and stress corrosion sensitivity based on the low alloy high strength steel welded joint was systematically studied in NaCl solution at the hightemperature. Through comparatively measuring the stress corrosion crack (SCC) rate in the different area of base metal (BM) and weld metal (WM) respectively, the SCC resistance in welded joint was evaluated and analysed. The SCC test indicated that the WM presented a lower crack growth rate (CGR) compared to the BM. The reason for that was mainly ascribed to the columnar of WM that impeded the crack growth in the vertical direction of stress. Meanwhile, the interwoven microstructure of nonparallel ferrite strips and fine acicular ferrite in the WM led to the zigzag propagated path and decreased the CGR.