Martensitic and ferrite stainless steel in lactic acid are usually very poor, and austenitic stainless steel is widely used in the food industry and dairy industry. 18-8 steel can be used for the processing work, 304 steel under 38 ℃ for storage of lactic acid is the best. Concentrated hot lactic acid solution may cause serious corrosion of non-molybdenum austenitic stainless steel, so 316L stainless steel and 317L stainless steel are the most suitable materials at high temperatures.
In the treatment of the organic acids such as oxalic acid, carbonic acid, citric acid, naphthenic acid, tartaric acid, oleic acid, stearic acid, palmitic acid, benzene dicarboxylic acid and malic acid and handling these acid mixture of austenitic stainless steel is the most commonly used. Generally speaking, 302 and 304 steel are suitable for use at room temperature and are used as storage and processing equipment for these acids. At higher temperatures austenitic stainless steel is durable in such as citric acid and oleic acid, and in some acids, such as malic acid and naphthenic acid, require the use of molybdenum steel 316L or 317L. They are used to make oil and acid distillers and malic acid and benzoate evaporator.
Source: China Steel Pipe Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)