Stainless steel corrosion
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Chloride ions cause severe corrosion in austenitic stainless steels, especially in those used in cooling systems; therefore, it is important to determine the appropriate level of chloride ions in the circulating water.
Materials selection for chloride corrosion rings https://bbs.hcbbs.com/thread-3263253-1-1.html
It is necessary to consider the return temperature of the circulating water; generally, this temperature should not exceed 50°C, as exceeding this limit can lead to corrosion and scaling. Additionally, the chloride concentration in the circulating water should not be higher than 500 ppm – the lower, the better
It is recommended to use polyaniline coatings for corrosion protection; the saturated salt water we use contains 240,000 ppm of chloride ions
At present, many enterprises that have been approved to draw water from downstream rivers and lakes have a chloride content in their raw water or recycled water at levels of 150–200 mg/L. If a concentration ratio of about 5 is maintained during the use of recycled water, then the chloride content in such recycled water rises to 750–1000 mg/L. The corrosion protection and material selection for circulating water pipes, coolers, cooling jackets, etc. are new challenges that have arisen in recent years. In a midstream section of a river where the chloride content in the raw water was only 30–40 mg/L over twenty years ago, it is now as high as 100–120 mg/L.