This study investigated stress corrosion cracking (SCC) of A588 steel welds
as determined by U-bend immersion tests and slow strain rate tensile (SSRT
) tests to evaluate the steel's cracking susceptibility in various regions
of the weldments, The immersion test results indicated that the fusion zone
(FZ) had better corrosion resistance than the other regions in the weld. I
t was also demonstrated that the columnar grain boundaries exhibited a high
er resistance to corrosion than the grain interior of the FZ, However, the
coarse elongated ferrite in the FZ is susceptible to hydrogen embrittlement
(HE), which results in the formation of microcracks. As a result, a severe
degradation of the weld's tensile properties in the saturated H2S solution
was observed. Scanning electron microscope (SEM) fractographs of tensile s
pecimens reveal a cleavage fracture in the coarse-grained heat-affected zon
e (CGHAZ) and featherlike rupture in the FZ, both indicating a high sensiti
vity to HE.