ASTM A182 F51 UNS S31803 Duplex 2205 Specification

ASTM A182 F51 UNS S31803 Duplex 2205 Specification

ASTM A182 F51 (UNS S31803), commonly known as Duplex Stainless Steel 2205, is a duplex (austenitic–ferritic) stainless steel forging grade used for the manufacture of pipe flanges, forged fittings, valves, and pressure-retaining components.
This page provides the complete ASTM A182 F51 Duplex 2205 Specification, including chemical composition, mechanical properties, heat treatment requirements, standards, and typical applications.

ASTM A182 Standard

ASTM A182 is the standard specification for forged or rolled alloy and stainless steel flanges, forged fittings, valves, and parts for high-temperature and corrosive service.

ASTM A182 F51 Material Specification

  • Material Grade: ASTM A182 F51

  • UNS Number: S31803

  • Common Name: Duplex Stainless Steel 2205

  • Standard: ASTM A182 / ASME SA182

  • Material Type: Duplex Stainless Steel (Austenitic–Ferritic)

  • Service Condition: High-strength and corrosion-resistant applications

ASTM A182 F51 duplex 2205 combines the advantages of austenitic and ferritic stainless steels, offering high strength and superior resistance to stress corrosion cracking.

 ASTM A182 F51 Products

ASTM A182 F51 material is commonly supplied in the following forged forms:

  • Pipe flanges (Weld Neck, Slip-On, Blind, Socket Weld, Threaded)

  • Forged fittings (Elbows, Tees, Reducers, Couplings)

Chemical Composition of ASTM A182 F51 (Typical, %)

Element Requirement
Carbon (C) 0.03 max
Manganese (Mn) 2.00 max
Phosphorus (P) 0.030 max
Sulfur (S) 0.020 max
Silicon (Si) 1.00 max
Chromium (Cr) 21.0 – 23.0
Nickel (Ni) 4.5 – 6.5
Molybdenum (Mo) 2.5 – 3.5
Nitrogen (N) 0.08 – 0.20

Mechanical Properties

Property Requirement
Tensile Strength ≥ 620 MPa (90,000 psi)
Yield Strength ≥ 450 MPa (65,000 psi)
Elongation ≥ 25 %
Hardness ≤ 290 HB

ASTM A182 F51 provides approximately twice the yield strength of austenitic stainless steels such as 304 and 316.

Heat Treatment Requirements

ASTM A182 F51 forgings shall be supplied in the solution annealed condition.

Typical heat treatment:

  • Solution annealed at 1020–1100°C (1870–2010°F)

  • Followed by rapid cooling (water quench or equivalent)

Proper heat treatment is essential to achieve the correct 50/50 austenite–ferrite microstructure and optimal corrosion resistance.

Dimensions & Applicable Standards

ASTM A182 F51 flanges and fittings are manufactured according to the following standards:

  • ASME B16.5 – Pipe Flanges and Flanged Fittings

  • ASME B16.47 – Large Diameter Steel Flanges

  • ASME B16.11 – Forged Fittings

  • ASME B16.34 – Valves

Pressure-temperature ratings are governed by the applicable ASME standard.

Testing & Inspection

ASTM A182 F51 duplex 2205 forgings are typically subjected to:

  • Chemical composition analysis

  • Tensile testing

  • Hardness testing

  • Microstructure verification (when required)

  • Dimensional and visual inspection

  • Non-destructive testing (UT / PT, if specified)

Mill Test Certificates EN 10204 3.1 are normally supplied.

Download ASTM A182 F51 Duplex 2205 Specification PDF

Download the complete ASTM A182 F51 UNS S31803 Duplex 2205 Specification PDF, including:

  • Chemical composition limits

  • Mechanical property requirements

  • Heat treatment conditions

  • Dimensional and pressure references

👉Download astm_a182_f51_uns_s31803_duplex_2205_specification
👉 Download ASME SA182 Standard PDF

ASTM A182 F51 Duplex 2205 FAQ

Q1: Is ASTM A182 F51 the same as Duplex 2205?
Yes. ASTM A182 F51 corresponds to Duplex Stainless Steel 2205 with UNS designation S31803.

Q2: What is the difference between S31803 and S32205?
S32205 (F60) is an enhanced version of duplex 2205 with tighter composition control and improved corrosion resistance.

Q3: Can ASTM A182 F51 be used for flanges and forged fittings?
Yes. It is commonly used for flanges, forged fittings, valves, and pressure-retaining components.

ASTM A182 F51 vs F60 – FAQ

Q1: Can F51 be replaced by F60?
Yes. F60 can generally replace F51, but not vice versa.

Q2: Is F60 stronger than F51?
Mechanical strength is similar; F60 mainly improves corrosion resistance.

Q3: Are F51 and F60 dimensionally interchangeable?
Yes. Both follow the same ASME dimensional standards.

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