Resistance of stainless steels to crevice corrosion, SCC and corrosion of welded joints

A critical factor in improving the efficiency and longevity of geothermal systems is the careful selection of materials capable of withstanding extreme environmental conditions, including high temperatures, corrosive fluids, and mechanical stresses. This paper aims to provide insights into various grades of stainless steel that are particularly suitable for geothermal energy applications, with a focus on their corrosion resistance in brine.
For well construction it is paramount to assess the influence of design features, such as crevices, bends and weldments, in the corrosion resistance of the materials, reason why we also included those assemblies in our study. The tested grades were S31603, N08904, S32205, S32750, S31254 and N08935.
This study combines historical and new data to obtain an overview of how various stainless steel grades behave in different brines. Recognizing that the risk of corrosion in brines is influenced by various factors, this research evaluates the performance of stainless steels against localized corrosion in chloride concentrations of 20,000, 100,000 and 200,000 ppm, solutions at a temperature of 90°C, pH 4 and 8, with and without aeration.
The findings of this study outline the localized corrosion performance of stainless steel, offering valuable insights for material selection in geothermal applications. Furthermore, the discussion thoroughly explores the factors affecting the corrosion resistance of stainless steel, including chloride content, oxygen levels, and solution pH, thereby contributing to a deeper understanding of the materials best suited to withstand the challenges posed by geothermal environments.