Stress Corrosion Cracking Behavior of X90 Pipeline Steel and Weld in Air and Near-neutral NS4 Solution

Stress corrosion cracking (SCC) behavior of weld and base metal of X90 pipeline in air and near-neutral NS4 solution was investigated by using slow strain rate test. The results indicate that the base metal and weld were sensitive to SCC to a certain degree in near-neutral NS4 solution. The sensitivity of weld was higher than that of base metal and there was mainly plastic loss. The tensile fracture of base metal and weld in air exhibited typical dimple-microvoid ductile fracture, and the tensile fracture in NS4 solution exhibited mixed fracture characteristics.