Super Duplex S31803 Spiral Wound Gasket NACE MR0175 STANDARD

Super duplex S31803 spiral wound gasket is made of V-shape Uns S31803 tape and soft PTFE filler or graphite filler, it has superior resistance to chloride pitting and crevice corrosion as compared to SS 317L spiral wound gasket. The S31803 spiral wound gasket has outstanding corrosion resistance to seawater and most concentrations of sulphuric acid. In addition, it is also resistant to sulphide stress corrosion cracking.

UNS S31803 also called 2205 Duplex, it is a duplex grade with a ferritic-austenitic microstructure. The alloy consists of around 40-50% ferrite in the annealed condition. The duplex microstructure has the high strength of the ferritic grades whilst retaining the corrosion resistance of the austenitic grades. It is not uncommon to see the metal used as a practical solution to chloride-induced stress cracking.

The Resistance of S31803 to Corrosion

UNS S31803 is resistant to intergranular corrosion. It has better corrosion resistance than that of other austenitic stainless grades such as 316, with higher resistance to stress corrosion cracking to that of either 304 or 316 stainless grades. Pitting corrosion and crevice corrosion is higher than that of 316. Due to its higher corrosion resistance UNS S31803 has better fatigue strength in corrosive environments than that of other austenitic stainless steel specifications.