Stress corrosion cracking of LDX 2101~® duplex stainless steel in chloride solutions in the presence of thiosulphate

摘要

SCC behaviour of a LDX 2101~® stainless steel was studied through SSRT in a 20% NaCl solution at 80 ℃ and in the standard NACE TM-0177 solution at 25 ℃ in the presence of S_2O_3~2. Some tests were also performed in the NACE solution at various pH or temperatures. The LDX 2101~® was susceptible to SCC in the presence of small thiosulphate concentrations. The selective corrosion of the ferrite phase became the main cause of failure when the thiosulphate concentration was increased to 0.1 M in the 20% NaCl at 80 ℃ or when NACE solution temperature was raised to 80 ℃.