Evaluation of the susceptibility to stress corrosion cracking of 304 steel in 0.002M Thiosulphate solution by three methods of tests

Abstract

Cracking in materials is a serious problem, which occurs when the material is subjected to extreme conditions or when phenomena such as stress corrosion cracking (SCC) occur. These cracks tend to grow over time due to the sensitization that the material presents once the phenomenological factors such as stresses and a specific environment are combined.
Thiosulfate can be found in many situations as a consequence of aerial oxidation of sulfates, produced by sulfate-reducing bacteria in anaerobic parts of systems or particularly from the degradation of ion exchange resins in the nuclear industry. The cracking system of thiosulfate-sensitized stainless steel is interesting for many reasons. Very dilute neutral solutions have been shown to induce cracking. Velocities of the order of 8 μms-1 are much higher than the highest current densities measured on the bare surface, implying that thiosulfates stimulate anodic dissolution of Chromium-depleted regions.
In the present work, the effect of sensitization in 304 stainless steels in the presence of sodium thiosulfate 0.002M was studied, using the slow strain rate test technique, (SSRT), compact tension (CT) tests and cantilever beams (CB). finding that 304 steel presents susceptibility to SCC.