With excellent resistance to sulfuric acid dew-point corrosion, NAS 155N (UNS S31727) is a stainless steel custom made for the heat exchangers, flues, and chimneys of heavy oil-fired boilers. This alloy is suitable in a wide range of material applications for antipollution equipment and other devices exposed to a sulfuric acid environment. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-1059. Producer or source: Nippon Yakin Kogyo Company Ltd.