Sandvik SAF 2507~R in service for twenty years in seawater applications

摘要

Sandvik SAF 2507~R, UNS S32750 is a super duplex (austenitic-ferritic) stainless steel with a minimum Pitting Resistant Equivalent, PRE, of 42.5. It was originally developed for seawater cooling and is suited for service in highly corrosive environments, being characterized by excellent resistance to pitting and crevice corrosion, a high resistance to general corrosion, high resistance to corrosion fatigue, high mechanical strength, and physical properties that offer design advantages. Further, it has good weldability and the matching filler metal gives the welds properties close to the base material. The alloy was the first material used for large scale stainless steel tube umbilicals due to its good resistance to crevice corrosion in seawater and high fatigue properties.