ASTM A276 UNS S31803 vs ASTM A182 F51
Apr 29, 2026
Leave a message
What is ASTM A276 uns S31803 material bar?
ASTM A276 UNS S31803 bar is a specification for hot or cold-finished Duplex 2205 stainless steel bars. It features a 50:50 ferritic-austenitic microstructure, offering high strength, excellent corrosion resistance, and high resistance to stress corrosion cracking. These bars are widely used in oil/gas, chemical processing, and marine environments.
What material is ASTM A182 F51 equivalent to?
ASTM A182 F51 is primarily equivalent to UNS S31803 (22% Cr duplex stainless steel) and the European standard DIN 1.4462 (X2CrNiMoN22-5-3). Known commonly as Alloy 2205, it is a versatile austenitic-ferritic stainless steel used for high-strength, corrosion-resistant forged products, often dual-certified as F60 (UNS S32205).
Chemical Composition (Typical Weight %)
Both standards follow the same chemistry for the S31803 grade.
| Element | Chromium (Cr) | Nickel (Ni) | Molybdenum (Mo) | Nitrogen (N) | Carbon (C) |
| Value (%) | 21.0 – 23.0 | 4.5 – 6.5 | 2.5 – 3.5 | 0.08 – 0.20 | ≤ 0.030 |
| PREN | 34 - 36 | 34 - 36 | 34 - 36 | 34 - 36 | - |
Mechanical Properties
The requirements are nearly identical, though testing methods may vary by product form.
| Property | A276 S31803 (Bar) | A182 F51 (Forging) |
| Tensile Strength (Rm) | ≥ 620 MPa (90 ksi) | ≥ 620 MPa (90 ksi) |
| Yield Strength (Rp 0.2) | ≥ 450 MPa (65 ksi) | ≥ 450 MPa (65 ksi) |
| Elongation (A50mm) | ≥ 25% | ≥ 25% |
| Hardness (Brinell) | ≤ 290 HBW | ≤ 290 HBW |
| Hardness (Rockwell C) | ~ 30 HRC | ~ 30 HRC |
ASTM A276 UNS S31803 vs. ASTM A182 F51: Applications
ASTM A276 UNS S31803 and ASTM A182 F51 are both 22% chromium duplex stainless steels (often called 2205) with identical chemical compositions, but they serve different purposes. ASTM A276 covers bars and shapes for general manufacturing, while ASTM A182 F51 specifies forged components (flanges, fittings, valves) for high-pressure, high-temperature service.
What is the difference between A479 S31803 and A182 F51?
ASTM A479 S31803 and A182 F51 are the same core 22% Chromium duplex stainless steel (UNS S31803/2205). The primary difference is the product form: A479 covers hot-rolled/cold-finished bar and stock for pressure vessels, while A182 F51 covers forged components like flanges and fittings.
Can I use A276 S31803 round bar to make a flange?
No. Flanges for pressure service must meet ASTM A182. Using a bar to machine a flange might be okay for a decorative part, but for oil & gas or chemical piping, the forging process required by A182 is necessary for grain structure and pressure integrity.
UNS S31803 vs F51: Which one is better for marine use?
Both are equally excellent as they are the same material (Duplex 2205). The choice depends purely on the shape you need: a bar (A276) for a propeller shaft or a flange (A182) for a hull connection.
UNS S31803 vs F51: Are they the same price?
Generally, A182 F51 forgings are more expensive than A276 S31803 bars per kg because of the additional forging and machining labor involved.
In addition to supplying bars, Gnee offers a complementary range of flanges, elbows, and fasteners produced from the same heat number. This resolves the issue of welding process instability,often encountered by end-users that stems from chemical composition discrepancies (such as fluctuations in nickel and nitrogen levels) in materials sourced from different suppliers.
We welcome on-site inspections by authoritative third-party agencies, including SGS, TUV, BV, and Lloyd's. We provide comprehensive Material Test Certificates (MTCs) compliant with EN 10204 3.1, which include detailed results for chemical analysis, tensile testing, impact testing, hardness testing, and 100% Ultrasonic Testing (UT).
GNEE S31803 / F51 Product Forms
| Standard | Product Form | Size Range | Surface / Processing State |
|---|---|---|---|
| ASTM A276 | Round Bar | Diameter: 5.0 mm – 500 mm | Bright, Peeled, Black |
| ASTM A276 | Hex Bar / Square Bar | Across Flats / Side Length: 5 mm – 150 mm | Cold Drawn, Polished |
| ASTM A182 | Forged Flanges | 1/2" – 48" (PN16 – PN420) | WN, SO, Blind, Threaded, SW |
| ASTM A182 | Forged Fittings | 1/2" – 4" (3000#, 6000#) | Elbow, Tee, Coupling, Union |
| ASTM A182 | Custom Forgings | Rings, Stepped Shafts, Disc Forgings | Rough Machined or Finished Machined |
Send Inquiry