ASTM A182 F51 Weld Neck Flanges Manufacturer
We are a professional manufacturer in producing high-performance ASTM A182 F51 weld neck flanges Our ASTM A182 F51 weld neck flanges are manufactured from duplex stainless steel F51 (UNS S31803), offering a perfect combination of high strength, resistance to stress corrosion cracking, and resistance to pitting — even in aggressive environments.
Weld Neck Flanges are high-strength flanges designed to be butt-welded to piping systems, offering excellent stress distribution and leak-proof performance. They are widely used in critical applications involving high pressure, high temperature, or repeated thermal cycles.
A Weld Neck Flange also called WN Flange,is a flange with a long tapered hub that gradually transitions to the wall thickness of the pipe or fitting. It is butt-welded to the pipe, providing a strong and permanent connection.
ASTM A182 F51 Weld Neck Flanges specification:
- Material: ASTM A182 F51 (UNS S31803) — duplex stainless steel
- Type: Weld Neck Flanges
- Face:Raise Face,Ring Joint type
- Size: 1/2” to 48” (or custom sizes upon request)
- Pressure Rating: 150#, 300#, 600#, 900#, 1500#, 2500#
- Standard: ASME, ANSI, ASTM
- Applications: Oil and Gas, Petrochemical, Chemical, Paper & Pulp, Power Generation, Water Treatment
ASTM A182 F51 also called F51 or S31803,it is duplex stainless steel and is also called “duplex 2205” or “alloy 2205”.
DUPLEX STEEL UNS S31803 FLANGES / A240 UNS S32205/S31803 /
EURONORM: 1.4462 X2CrNiMoN 22.5.3 / AFNOR: Z3 CrNi 22.05 AZ / DIN: W.Nr 1.4462 :
Chemical Composition of ASTM A182 F51 flanges
| Element | Min | Max |
|---|---|---|
| Carbon (C) | 0 | 0.030 |
| Silicon (Si) | 0 | 1.0 |
| Manganese (Mn) | 0 | 2.0 |
| Phosphorus (P) | 0 | 0.030 |
| Sulfur (S) | 0 | 0.015 |
| Chromium (Cr) | 21 | 23 |
| Nickel (Ni) | 4.5 | 6.5 |
| Molybdenum (Mo) | 2.5 | 3.5 |
| Nitrogen (N) | 0.08 | 0.20 |
| Iron (Fe) | balance | balance |
ASTM A182 F51 Flanges Mechanical Properties
| Requirement | |
|---|---|
| Tensile Strength | 620 MPa (90 ksi) minimum |
| Yield Strength (0.2%) | 450 MPa (65 ksi) minimum |
| Elongation in 2 inch | 25% minimum |
| Hardness (Brinell or Rockwell) | HB 293 max (or) HRC 31 max |
| Impact Energy (Charpy V-Notch) | 27 J minimum at -40°C |
Heat Treatment of F51 Flanges
✅ Solution Annealing at 1040°C (1900°F) or higher, followed by rapid quenching in water or air.
Test Requirement of our ASTM A182 F51 Flanges
Chemical Tests
Mechanical Tests
Tensile Test
Hardness Test
Impact (Charpy V-Notch) Test
Why Choose our ASTM A182 F51 Flanges?
ASTM A182 F51 flanges are widely used in demanding industries such as oil and gas, chemical processing, marine, and seawater applications. Thanks to their duplex stainless steel composition, they provide:
- High tensile strength and durability, with a minimum tensile strength of 620 MPa (90 ksi)
- Excellent corrosion resistance, particularly against chloride-induced stress corrosion and pitting
- Good weldability and toughness, making them suitable for extreme conditions
- Resistance to thermal fatigue and cracking, ideal for high-pressure and high-temperature environments
Applicable Standards for A182 F51 Flanges
Our ASTM A182 F51 flanges comply with international standards such as ASME B16.5 for pipe flanges and ASME B16.47 for large diameter flanges. They are available in various types, including weld neck, slip-on, blind, threaded, and socket weld flanges, across a wide range of sizes and pressure classes (150# to 2500#).
comparison between ASTM A182 F51 and A182 F60
| Feature | ASTM A182 F51 | ASTM A182 F60 |
|---|---|---|
| Material Type | Duplex Stainless Steel (Standard Duplex) | Super Duplex Stainless Steel |
| UNS Number | S31803 | S32550 |
| Chemical Composition | – Cr: ~21-23% | – Cr: ~24-26% |
| – Ni: ~4.5-6.5% | – Ni: ~6-8% | |
| – Mo: ~2.5-3.5% | – Mo: ~5-6.5% | |
| – N: ~0.08-0.20% | – N: ~0.24-0.32% | |
| Mechanical Properties | – Tensile Strength: min 620 MPa (90 ksi) | – Tensile Strength: min 758 MPa (110 ksi) |
| – Yield Strength: min 450 MPa (65 ksi) | – Yield Strength: min 620 MPa (90 ksi) | |
| Corrosion Resistance | Good resistance to chloride stress corrosion cracking | Superior resistance to chloride stress corrosion cracking and pitting |
| Typical Applications | Chemical processing, oil & gas, seawater handling | More aggressive environments like offshore drilling, chemical plants with strong chloride presence |
| Cost | Lower compared to F60 | Higher due to higher alloy content |
| Microstructure | Balanced ferrite & austenite (~50/50) | Balanced, but higher alloy content enhances phase stability |
| Heat Treatment | Solution annealed | Solution annealed |
Conclusion
- F51 is your standard duplex stainless steel, suitable for many corrosive environments but with moderate corrosion resistance.
- F60 is a super duplex grade with higher Cr, Mo, and N content, giving it much higher strength and enhanced corrosion resistance, especially against chlorides and stress corrosion cracking.
⬇️ Download ASTM A182 Lastest Edition standard Now (PDF)
⬇️ Download ASTM A182 F51 specification Now (PDF)
Download the Dimension of ASME B16.5 Weld neck Flange
A typical enquiry/order description for A182 F51 WN FLANGE
Name: A182 F51 WN FLANGE, 8IN, CL 600, RF, ASME B16.5
Type: WN Flanges.
Material: ASTM A182 F51.
Size: 8 Inch.
Pressure: CL 600.
Standard: ANSI B16.5.
Ends: RF.
We manufacture ASTM A182 F51 Weld Neck Flanges in compliance with ASME B16.5, EN 1092-1, DIN, and other global standards. Each flange is 100% tested and certified, with full traceability, PMI test reports, MTC EN 10204 3.1/3.2, and third-party inspection if required.
ASTM A182 F51 vs ASTM A182 F60
Both A182 F51 and A182 F60 are forged stainless steel grades used for flanges, fittings, and pressure components in corrosive environments.However there are slightly difference between those 2 grades
ASTM A182 F60 also known as Duplex stainless 2205 (UNS S32205) is a chromium-nickel- molybdenum-nitrogen stainless steel. UNS S32205 has high strength and corrosion resistance at temperatures up to 316°C. UNS S32205 is a duplex grade with a ferritic-austenitic microstructure. The alloy consists of around 40-50% ferrite in the annealed condition.
Chemical Composition Comparison (wt%) Comparison
| Element | F51 | F60 |
|---|---|---|
| UNS Designation | S31803 | S32205 |
| Material Description | 22% Cr, 5.5% Ni, modified with nitrogen | 22% Cr, 5.5% Ni, 3% Mo, modified with nitrogen |
| Carbon (C), max | 0.030 | 0.030 |
| Manganese (Mn), max | 2.00 | 2.00 |
| Phosphorus (P), max | 0.030 | 0.030 |
| Sulfur (S), max | 0.020 | 0.020 |
| Silicon (Si), max | 1.00 | 1.00 |
| Nickel (Ni) | 4.5 – 6.5 | 4.5 – 6.5 |
| Chromium (Cr) | 21.0 – 23.0 | 22.0 – 23.0 |
| Molybdenum (Mo) | 2.5 – 3.5 | 3.0 – 3.5 |
| Nitrogen (N) | 0.08 – 0.20 | 0.14 – 0.20 |
| Other Elements | — | — |
Related Products
- ASTM A182 F51 Blind Flange
- ASTM A182 F53 Weld Neck Flange
- ASTM A815 UNS S31803 Pipe Fittings
- ASTM A790 UNS S31803 Seamless Pipes
- Duplex 2205 Round Bars
