Lean Duplex Stainless Steels (LDSS) have now been used or are being considered as substitutes for several well-established materials, in various applications. Examples include: - Substitution for Types 304L and 316L for increased strength, SCC and general corrosion resistance, and price stability. - Substitution for coated carbon steel in structural applications, for corrosion resistance and low life cycle costs. - Substitution for Super Duplex Stainless Steels in subsea umbilicals via an external Zn coating. - Substitution for 2205 in Oil Gas applications where the need for strength sometimes overrides corrosion resistance requirements, such as top-side piping, down- hole instrumentation tubing and heat exchangers in down-stream refineries. - Substitution for 13Cr Super Martensitic Stainless Steels for mild and moderate (< = 10 mbar H_2S) subsea flow line environments. Alloy substitution is a more important consideration in materials selection than ever before because of: - A greater knowledge of alloy limitations in field environments. - The need to account for both initial and life-cycle cost considerations. - Project planning difficulties resulting from raw material surcharge volatility. - Opportunities for innovative substitution to achieve equivalent performance at a lower cost, via weight reductions, coatings, tooling modifications, lubricants, etc. - High and volatile costs of raw materials. This paper will concentrate primarily on AL 2003~(TM) LDSS (UNS S32003) as a substitute for Type 316L stainless steel. Comparative data will be presented including corrosion test data in various media, mechanical test data, and design strength limits. Examples of applications will be given where S32003 LDSS has displaced Type 316L based on the stated considerations.
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