Bar and Rod
Plate and Sheet
Strip
Pipe and Tube
Wire
Welding
Powder Material
Cast Products
Forged Products
Fittings
Fastening
Round Bar:
φ2–500 mm, 1–6 m length
Flat/Square Bar:
4–100 mm thickness/width
Hex Bar:
A/F 3–100 mm
Hollow Bar:
OD 20–300 mm
Sheet:
0.3–6 mm thickness
Medium Plate:
6–25 mm thickness
Heavy Plate:
25–100 mm thickness
Standard Strip:
0.05–3 mm thick,
10–600 mm wide
Precision strip:
0.01–0.5 mm thick,
tight tolerance ±0.005 mm
Foil:
0.005–0.1 mm thick
Seamless Tube:
OD 6–450 mm,
WT 1–50 mm,
1–12 m length
Welded Tube:
OD 10–600 mm,
WT 1–20 mm
Capillary Tube:
OD 1–10 mm,
WT 0.1–2 mm
Wire Form:
Cold Drawn Wire,
Bright Wire,
Spring Wire,
Fine Wire,
Ultra-fine Wire
General Diameter:
φ0.1–10 mm
Coil Weight:
50–500 kg,
customizable tolerance
Solid Wire:
φ0.8–4.0 mm
Flux-cored Wire:
φ1.2–4.0 mm
Welding Rod:
φ2.0–5.0 mm
Powder Form:
AM 3D Printing Powder,
Spherical Powder,
Gas-atomized Powder,
Water-atomized Powder
Particle Size:
10–150 μm
Sphericity:
≥90% for AM grade
Cast Ingot:
φ200–800 mm
Precision Casting:
min wall 0.5 mm
Cast Pipe:
OD 100–600 mm,
WT 10–50 mm
Forged Bar:
Φ35–500 mm
Forged Ring:
OD 200–2000 mm
Forging Weight:
1–5000 kg
Fittings Form:
Elbow, Tee, Reducer, Flange, Cap, Outlet, Lap Joint
Size range:
1/2''–24'' (DN15–DN600)
Wall thickness:
Sch10–Sch160, STD, XS, XXS
Pressure Class:
150–2500 LB
Fastening Form:
Bolt, Nut, Screw, Stud, Washer, Pin, Rivet
Metric: M3–M64
Imperial: #4–2.5''
Length: 6–500 mm
S31803 is the most widely used ferritic-austenitic (duplex) stainless steel, with a microstructure of roughly equal ferrite and austenite. This datasheet presents the material within the American standard system.
With about 22% chromium, 5.5% nickel, 3.2% molybdenum and a deliberate nitrogen addition (0.08-0.20%), S31803 offers roughly twice the yield strength of standard austenitic grades, together with excellent resistance to chloride pitting, crevice corrosion and chloride stress-corrosion cracking, to which austenitic grades are prone. Its PREN is typically 34-38. The S32205 composition is a refined (higher minimum Cr/Mo/N) range of the original S31803, giving more consistently guaranteed corrosion resistance.
Typical applications include oil-and-gas equipment and subsea pipelines, pressure vessels, chemical-process heat exchangers and reactors, marine and desalination equipment, and pulp-and-paper digesters and bleaching plant.
Values for the solution-annealed condition.
| Property | Value | Unit |
|---|---|---|
| Density | 7.8 | g/cm³ |
| Melting range | 1385-1445 | °C |
| Young's modulus (20 °C) | 200 | GPa |
| Thermal conductivity (20 °C) | 16 | W/m·K |
| Coefficient of thermal expansion (20-100 °C) | 13 | µm/m·°C |
| Specific heat (20 °C) | 450 | J/kg·K |
| Magnetic response | Ferromagnetic (duplex) | — |
Composition per ASTM A240.
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Iron | Fe | Balance | — | Base element |
| Chromium | Cr | 21.0 | 23.0 | Ferrite former; corrosion resistance |
| Nickel | Ni | 4.5 | 6.5 | Austenite former; phase balance |
| Molybdenum | Mo | 2.5 | 3.5 | Pitting + crevice resistance |
| Nitrogen | N | 0.08 | 0.20 | Austenite former; strength; pitting |
| Manganese | Mn | — | 2.0 | Deoxidiser |
| Silicon | Si | — | 1.0 | Deoxidiser |
| Carbon | C | — | 0.030 | Low (intergranular resistance) |
| Phosphorus | P | — | 0.030 | Residual impurity |
| Sulphur | S | — | 0.020 | Residual impurity |
Nominal: 22Cr-5.5Ni-3.2Mo-N duplex. PREN ~34-38. (S32205 uses tighter minima: Cr 22-23, Mo 3.0-3.5, N 0.14-0.20.)
Solution-annealed condition, per ASTM A240 for UNS S31803.
| Property | Value | Unit |
|---|---|---|
| Tensile strength | >=620 | MPa |
| 0.2% yield strength | >=450 | MPa |
| Elongation at break | >=25 | % |
| Brinell hardness | <=293 | HB |
| Rockwell hardness | <=31 | HRC |
Confirm against the mill test report.
| Environment | Performance | Notes |
|---|---|---|
| Chloride SCC | Excellent | Key duplex advantage over austenitics |
| Chloride pitting | Very good | Cr + Mo + N (PREN ~34-38) |
| Crevice corrosion | Very good | Better than 316L |
| General (oxidizing) | Very good | High chromium |
| Sulphide / sour | Good | Listed in NACE MR0175 |
Far better chloride-SCC resistance than austenitic 304/316, with roughly double the strength.
Not hardenable by heat treatment; properties are set by solution annealing and phase balance.
Solution Anneal approximately 1020-1100 °C, followed by rapid water quench to retain the balanced ferrite-austenite structure and avoid embrittling intermetallic phases. Avoid prolonged exposure in the 300-1000 °C range (sigma-phase / 475 °C embrittlement).
Good weldability by common fusion methods; use 2209 (over-alloyed) filler and control heat input (typically <=1.5 kJ/mm) to maintain phase balance.
| Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG | Excellent | ER2209 (over-alloyed duplex) |
| GMAW / MIG | Good | ER2209 |
| SMAW / stick | Good | E2209 electrode |
No preheat; control interpass temperature and heat input; balanced weld retains corrosion resistance and toughness.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Machinability | Duplex; carbide tools, low cutting speeds, rigid setup |
| Work hardening | Significant; positive feeds, avoid dwelling |
| Coolant | Ample flood coolant |
Forming Processes
| Process | Notes |
|---|---|
| Hot forming | ~1230-950 °C; solution anneal + quench afterward |
| Cold forming | Higher forces than austenitics (high duplex strength) |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Oil & gas | Subsea pipelines, pressure vessels | Sour-service + SCC resistance |
| Chemical processing | Heat exchangers, reactors | Pitting + SCC resistance |
| Marine | Propeller shafts, desalination plants | Chloride SCC resistance |
| Pulp & paper | Digesters, bleaching equipment | Chloride + caustic resistance |
| Product Form | Standard | Notes |
|---|---|---|
| Plate, sheet and strip | ASTM A240 / ASME SA-240 · UNS S31803 / S32205 | — |
| Forgings / fittings / flanges | ASTM A182 / F60 | — |
| Bar and shapes | ASTM A276 / A479 · UNS S31803 | — |
| Seamless / welded tube | ASTM A789 · UNS S31803 | — |
| Seamless / welded pipe | ASTM A790 · UNS S31803 | — |
| Sour service | NACE MR0175 / ISO 15156 | Acid-gas applications |
Standard 22Cr ferritic-austenitic (duplex) stainless steel. UNS S31803 / S32205.
| UNS | Cr % | Ni % | Mo % | N % | Best Used For |
|---|---|---|---|---|---|
| S31803 | 21-23 | 4.5-6.5 | 2.5-3.5 | 0.08-0.20 | Standard duplex; broad chloride service |
| S32950 | 26-29 | 3.5-5.2 | 1.0-2.5 | 0.15-0.35 | N-bearing duplex (high Cr) |
| S31200 | 24-26 | 5.5-6.5 | 1.2-2.0 | 0.14-0.20 | N-bearing duplex |
| S32750 | 24-26 | 6.0-8.0 | 3.0-5.0 | 0.24-0.32 | Super duplex (higher PREN) |
| S31603 | 16-18 | 10-14 | 2.0-3.0 | — | Austenitic general service |
021-33556635
13371897780
651280525@qq.com
No. 600, Si Chuang Road, Songjiang District, Shanghai
