Experiment of stainless steel corrosion and scaling in geothermal water supply pipeline

The corrosion and scaling on the surface of the 304 stainless steel (SS) pipe in the flowing geothermal water at 50°C were studied using the circulating-water environment simulator.The effects of corrosion and scaling on mass concentration of ions in geothermal water, corrosion potential and mass of the SS pipe were discussed.The results show that the needlelike scales were accumulated on the surface of the sample.The pitting corrosion also occurs.With time increasing, the density of corrosion pits increases. Due to the corrosion, scaling and descaling on the surface, the concentrations of Ca²⁺ and Mg²⁺ decline significantly in the first 600 h, after that they keep constant. The corrosion potential of the SS pipe increases in the first 350 h, then it is stable at 0.044 V. The quality keeps increasing during the whole soaking process.