Effect of induced stress on the corrosion rate of medium carbon steel in saline environment

This study investigated how 0.33% medium carbon steel is affected by induced stress in a saline environment. Three geometries namely U-bend, C-ring and I-shape samples were formed representing varying degrees of stress level induced on the samples. The test specimens were subjected to static loading in saline environment containing 15.0 wt.%, 10.0 wt.% and 3.5 wt.% of sodium chloride (NaCl) for a typical exposure time of 31 days at ambient conditions of temperature and pressure. Weight loss method was used to estimate the corrosion rate in mils per year (mpy). The results of the experiment show that corrosion rate is maximum in samples with the highest stress level and in medium containing highest amount of dissolved chloride ions. The least corrosion rate occurred in samples with the least amount of chloride ions and in a non-stressed condition. It was inferred that the corrosion rate of 0.33%C steels increased with increasing tensile stress and chloride ions content of the medium.   Key words: Stress corrosion cracking, medium carbon steel, saline environment, corrosion rate.