Duplex Stainless Steel (2205 / F51 / S31803)
Engineering definition, metallurgical mechanisms, standard testing specifications, and manufacturing guidelines for closed-die forgings up to 50 kg.
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A dual-phase stainless steel possessing an approximate 50% austenitic and 50% ferritic microstructure, combining twice the yield strength of 316L with supreme chloride pitting resistance.
Technical Explanation & Metallurgical Principles
Duplex stainless steels (principally 22% Cr Duplex 2205 / 1.4462) deliver a Pitting Resistance Equivalent Number (PREN) ≥35. The dual-phase microstructure provides extraordinary immunity to chloride stress corrosion cracking (SCC), high yield strength (≥450 MPa), and excellent erosion-corrosion resistance in seawater.
Key Engineering Specifications & Parameters
| Technical Parameter / Metric | Engineering Benchmark / Value |
|---|---|
| Phase Balance | 40% to 60% Ferrite, balance Austenite (ASTM E562) |
| PREN Rating | ≥ 35 [%Cr + 3.3(%Mo) + 16(%N)] |
| Yield Strength | ≥ 450 MPa (nearly 2x SS 316L) |
Application at Jayesh Forge (Rajkot Plant)
Hot-forged in closed dies up to 50 kg for offshore topsides, subsea trees, and reverse osmosis desalination plants with ASTM A923 intermetallic phase validation.
Related Materials, Standards & Products
Engineered Product Lines
Related Metallurgical & Testing Terms
Super Duplex Stainless Steel (2507 / F53 / S32750)
An ultra-high-alloyed 25% Chromium duplex stainless steel with PREN ≥ 42, engineered for deepwater offshore subsea manifolds and boiling seawater service.
Pitting Resistance Equivalent Number (PREN)
A standardized mathematical formula that rates the localized pitting and crevice corrosion resistance of stainless steels based on their Chromium, Molybdenum, and Nitrogen content.
Ferrite (Alpha-Iron Phase)
The body-centered cubic (BCC) crystalline form of iron, stable at room temperature in unalloyed steels, exhibiting magnetic behavior and low carbon solubility.
Sigma Phase Embrittlement (σ-Phase)
An extremely hard, brittle intermetallic Fe-Cr-Mo phase that precipitates in duplex and high-chromium stainless steels between 600°C and 900°C, destroying impact toughness.
Questions Regarding Duplex Stainless Steel (2205 / F51 / S31803)
Slow cooling through the 600°C–900°C window precipitates brittle sigma (σ) and chi (χ) phases that destroy impact toughness and pitting corrosion resistance.
Request a Forging Quote with Duplex Stainless Steel (2205 / F51 / S31803) Compliance
Our Rajkot metallurgy desk is ready to review your technical drawings, testing protocols, and delivery schedules for custom closed-die forgings strictly up to 50 kg.