Lean Duplex Stainless Steel within the Oil and Gas Industry

摘要

Lean duplex stainless steels, such as LDX 2101~R, have an attractive combination of high mechanical strength and good corrosion properties, and can be candidates for use in oil and gas applications. In this paper data are presented for lean duplex steels in various types of tests and environments of relevance to such applications. They include not only sour service conditions, but also environments which can give rise chloride-induced stress corrosion cracking or pitting. The results show that LDX 2101~R has a resistance to localised corrosion above austenitic grade 4301 and superior resistance to stress corrosion cracking compared to standard austenitic grades. Testing in H2S environments shows no cracking of LDX 2101~R at 90°C and 0.15 bar H2S. However, as other types of corrosion can occur, such as selective corrosion, it is important to investigate the limits for lean duplex grades (PREN < 30) in regard to H2S, pH, chloride content and temperature so this important group of alloys can be included in NACE MR0175 / ISO15156-3 in the future.