UNS S31803 Pipe Supplier. Contact us to get free quote and sample!
S31803 (UNS S31803, also known as 2205 or F51), an austenitic-ferritic duplex stainless steel, achieves an exceptional balance of strength, corrosion resistance, and economic efficiency through precise control of the two-phase ratio (nearly a 50:50 golden ratio), earning it the recognition of the "gold standard" of duplex stainless steel. HT PIPE is a uns s31803 duplex Pipe supplier with 15+ export experience. Contact us for more information and quotes for free!
duplex ss uns s31803 chemical composition
Its unique chemical composition is based on the core design concept of high chromium, medium nickel, molybdenum, and nitrogen synergistic strengthening. Chromium (22.0–23.0%) forms a dense Cr₂O₃ oxide film, providing fundamental corrosion resistance. Molybdenum (3.0–3.5%) and nitrogen (0.14–0.20%) synergistically enhance pitting corrosion resistance. Nitrogen also inhibits the precipitation of harmful intermetallic phases (such as sigma phase), enhancing high-temperature stability. The combination of low carbon (≤0.030%) and nickel (4.5–6.5%) effectively reduces the risk of intergranular corrosion, while stabilizing the austenite phase and improving low-temperature toughness.
astm a240 s31803 Corrosion Resistance
- Sulfide Stress Cracking (SSC) Resistance: Certified to the stringent NACE MR0175/ISO 15156 Level II, it can safely operate in sour oil and gas environments containing H₂S, addressing the sensitivity of traditional austenitic stainless steel in sour environments.
- Pitting and Crevice Corrosion Resistance: In seawater injection systems and submarine pipelines containing high chloride concentrations, its critical pitting temperature (CPT) is ≥35°C, extending its service life by more than three times that of ordinary stainless steel, significantly reducing maintenance costs and environmental risks.
stainless steel 1.4462 High-Temperature and High-Pressure Adaptability
Stable performance in continuous operation below 250°C and can withstand short-term operating temperatures of 300°C, fully covering the majority of oil and gas production and processing temperature ranges (wellhead temperatures are typically ≤180°C).
duplex stainless steel s31803 Submarine Pipeline Systems
Submarine pipelines, the "arteries" of offshore oil and gas field development, are subject to extremely complex corrosive environments and mechanical loads. S31803 resists both external seawater corrosion (Cl⁻ ≈ 19,000 ppm) and internal media corrosion (H₂S/CO₂/Cl⁻ combination).
duplex steel uns s31803 Downhole Tools and Completion Equipment
In downhole environments with H₂S concentrations up to 5,000 ppm and temperatures up to 120°C, S31803's SCC threshold stress is more than three times higher than that of 316L, ensuring 20 years of failure-free service for critical tools such as completion packers and safety valves in sour gas fields.
s31803 stainless steel Platform Process Pipelines and Processing Facilities
Offshore platform topsides are known as "floating chemical plants," and their process pipelines directly handle oil and gas products containing corrosive media. S31803 provides a comprehensive solution, from wellhead manifolds, oil and gas separator inlet and outlet pipelines, to seawater injection systems.
s31803 steel Safety Protection and Specialty Components
Instrument Protection System: S31803 demonstrates excellent formability in processing micro-tubes (e.g., 26.7 x 7.82 mm). It is used for pressure sensor protection tubes and hydraulic control lines, maintaining a 3 mm inner bore accuracy while meeting 69 MPa operating pressure requirements.
