Duplex Steel UNS S31803 / S32205 Flanges Supplier in Mumbai, India | ASTM A182 F51 & F60
Nicorex Alloys is an ISO 9001 and ISO 14001 certified importer, stockist, and supplier of ASTM A182 F51 and F60 duplex flanges based in Mumbai, India. We provide these flanges manufactured according to the ASTM A182 standard.
Both grades cover the same base alloy: Duplex 2205 (Werkstoff 1.4462), but F60 (UNS S32205) has tighter composition controls that guarantee a PREN of 35 or above on every production heat. F51 (UNS S31803) is the original forging specification; its broader composition lets PREN go as low as 30 on heats at the lower end. Each of our stocks comes with dual-certified F60/F51, removing the need to verify PREN on individual mill test certificates. The 50/50 austenite-ferrite microstructure gives these flanges a minimum yield strength of 450 MPa (65 ksi). This strength allows thinner wall sections, lighter flanges, and reduced support steel (a crucial advantage on offshore platforms under strict weight budgets). PREN for F60 starts at 34.1 (calculated as %Cr + 3.3×%Mo + 16×%N at minimum composition) and typically reaches 36 at mid-range chemistry. Available types include WNRF, SORF, BLRF, SWRF, Threaded, Lap Joint, Long Weld Neck, RTJ, Spectacle Blind, and Reducing. Sizes range from NPS 1/2″ to 24″ as per ASME B16.5 and NPS 26″ to 60″ as per ASME B16.47. Pressure classes span 150 through 2500.
Every shipment includes EN 10204/3.1B mill test certificates, PMI reports, ASTM A923 intermetallic phase detection results, and full heat traceability. All flanges meet NACE MR0175/ISO 15156 for sour gas service. Key industries include offshore oil & gas production, chemical & petrochemical processing, desalination & water treatment, and more applications, as explained below.
ASTM A182 F51 / F60 Flanges Specifications
The specifications for ASTM A182 F51 and F60 duplex flanges, covering standards, sizes, pressure classes, and marking requirements, are listed below.
| Specifications | ASTM A182 / ASME SA182 |
|---|---|
| Standards | ANSI/ASME B16.5, B16.47, B16.48, MSS SP-44, EN-1092, DIN 2633/2635 |
| Grades | F51 (UNS S31803, 1.4462), F60 (UNS S32205, 1.4462) |
| Pressure Classes | 150# to 2500#, PN6 to PN64 |
| Size Range | 1/2″ to 48″ NB (DN15 to DN1200) |
| Face Types | RF, FF, RTJ, LJF, Tongue & Groove |
| Types | Weld Neck, Slip-On, Blind, Socket Weld, Threaded, Lap Joint, Long Weld Neck, Spectacle Blind, Orifice, RTJ, Reducing |
| Testing | Tension, hardness, ASTM A923, impact, PMI, ultrasonic |
| Certification | EN 10204/3.1, radiography reports |
Chemical Composition of ASTM A182 S31803 & S32205 Flanges
The chemical composition of F51 and F60, and their key alloying elements, as per ASTM A182, is provided in the table below.
| Element | Carbon (C) | Chromium (Cr) | Nickel (Ni) | Molybdenum (Mo) | Nitrogen (N) | Manganese (Mn) | Silicon (Si) | Phosphorus (P) | Sulfur (S) | Iron (Fe) |
|---|---|---|---|---|---|---|---|---|---|---|
| F51 (S31803) | ≤0.030 | 21.0–23.0 | 4.5–6.5 | 2.5–3.5 | 0.08–0.20 | ≤2.0 | ≤1.0 | ≤0.030 | ≤0.020 | Balance |
| F60 (S32205) | ≤0.030 | 22.0–23.0 | 4.5–6.5 | 3.0–3.5 | 0.14–0.20 | ≤2.0 | ≤1.0 | ≤0.030 | ≤0.020 | Balance |
F51 and F60 share the same base chemistry, but F60 raises the minimum Cr from 21.0% to 22.0%, Mo from 2.5% to 3.0%, and N from 0.08% to 0.14%. Those three shifts push the guaranteed PREN above 34, removing heat-to-heat variability that can drop S31803 to a PREN of 30.5 at worst-case composition. Specifying F60 removes the need to verify PREN on individual mill test certificates (a significant quality review advantage for EPC contractors managing large flange quantities).
Mechanical Properties of ASTM A182 F51 / F60 Flanges
F51 and F60 share identical mechanical minimums as per ASTM A182, except for tensile strength. Values for strength, elongation, hardness, and more are covered below.
| Property | Tensile Strength (min) | Yield Strength, 0.2% (min) | Elongation (min) | Hardness (max) | Charpy Impact at -46°C |
|---|---|---|---|---|---|
| F51 | 620 MPa (90 ksi) | 450 MPa (65 ksi) | 25% | 293 HB (31 HRC) | 54 J min (supplementary) |
| F60 | 655 MPa (95 ksi) |
Equivalent Grades of Duplex S31803/S32205 Flanges
| UNS | EN | Werkstoff | AFNOR | JIS | ISO |
|---|---|---|---|---|---|
| S31803/S32205 | 1.4462 | X2CrNiMoN22-5-3 | Z3CND22-05Az | SUS 329J3L | ISO 15156-3 Table A.3 |
Types of Duplex 2205 Stainless Steel Flanges Available
ASTM A182 F51/F60 duplex flanges are hot forged at 950–1150°C, solution annealed above 1020°C, and water quenched to achieve the balanced 50/50 austenite-ferrite microstructure. All standard flange configurations as per ASME B16.5 and B16.47 are available.
Duplex S31803 Weld Neck Raised Face Flange (WNRF)
Duplex F60 Blind Raised Face Flange (BLRF)
UNS S32205 Slip-On Raised Face Flange (SORF)
ASTM A182 F51 Socket Weld Raised Face Flange (SWRF)
DSS UNS S32205 F60 Threaded Flange
ASTM A182 F60 Lap Joint Flange
Duplex Steel UNS S31803 Orifice Flange
DSS S32205 Spectacle Blind Flange
Duplex UNS S31803 Ring Type Joint Flange ( RTJ)
Duplex F51 Reducing Flange
Duplex F60 Long Weld Neck Flange
Get Duplex Steel S31803 / S32205 Flanges at Competitive Prices
Pressure-Temperature Ratings for ASTM A182 F51 / F60 Flanges
F51 and F60 are both duplex 2205 grades, one under UNS S31803 and the other S32205, and ASME B16.5 groups them together in Material Group 2.8 for pressure ratings across Class 150 to 2500. You won’t find these flanges rated above 600°F (316°C) in the code because sigma phase embrittlement kicks in beyond that point, making them unsafe for higher temperature service.
| Temp (°F) | Temp (°C) | Class 150 | Class 300 | Class 400 | Class 600 | Class 900 | Class 1500 | Class 2500 |
|---|---|---|---|---|---|---|---|---|
| −20 to 100 | −29 to 38 | 290 | 750 | 1000 | 1500 | 2250 | 3750 | 6250 |
| 200 | 93 | 260 | 750 | 1000 | 1500 | 2250 | 3750 | 6250 |
| 300 | 149 | 230 | 720 | 960 | 1440 | 2160 | 3600 | 6000 |
| 400 | 204 | 200 | 665 | 885 | 1330 | 1990 | 3325 | 5540 |
| 500 | 260 | 170 | 605 | 805 | 1210 | 1815 | 3025 | 5040 |
| 600 | 316 | 140 | 555 | 740 | 1110 | 1665 | 2775 | 4625 |
Industrial Applications of 2205 Duplex Steel Flanges
ASTM A182 F51/F60 duplex flanges are the industry-standard forging grade for piping connections in moderate-to-aggressive chloride environments where 316L lacks pitting resistance and super duplex grades represent unnecessary cost.
- Platform piping from wellhead connections to separator nozzles and produced water treatment.
- Reactor column flanges, heat exchanger connections, and organic acid piping.
- RO pump discharge flanges, brine recirculation piping, and seawater intake connections.
- Seawater cooling, ballast water, and fire water piping flanges.
- ClO₂ bleaching stage flanges, acid leach circuit connections, and sanitary-grade food-contact piping.
- Flanged connections for coastal infrastructure. Stonecutters Bridge (Hong Kong) and Oresund Bridge (Denmark–Sweden) use Duplex 2205 components for splash zone resistance.
How to Order Duplex 2205 Flanges from Nicorex Alloys
To place an order for ASTM A182 F51/F60 duplex flanges, provide these following details:
- Material Grade: ASTM A182 F51 (S31803) or F60 (S32205); specify if dual certification is required.
- Flange Type: WNRF, SORF, BLRF, SWRF, Threaded, RTJ, Lap Joint, LWN, Spectacle Blind, Reducing.
- Size, Schedule/Bore, and Pressure Class (150 through 2500).
- Face Type: RF, FF, RTJ, Tongue & Groove.
- Quantity (pieces or kg).
- Documentation: EN 10204/3.1 MTC, PMI, ASTM A923, Charpy test temperature, ferrite range, NACE compliance.
- Project specs: NORSOK M-630, Shell DEP, or other operator standards.
- Special: ASTM G48 corrosion testing, hardness mapping, specific PREN minimum.
- Packaging: sea-worthy wooden cases per ISPM 15, rust inhibitor coating.
Frequently Asked Questions
What is the Difference Between ASTM A182 F51 and F60 Duplex Flanges?
F51 (UNS S31803) and F60 (UNS S32205) are both Duplex 2205 forging grades with a Werkstoff 1.4462. F60 requires Cr ≥22.0% (vs 21.0%), Mo ≥3.0% (vs 2.5%), and N ≥0.14% (vs 0.08%). These tighter ranges guarantee PREN ~35 across all heats. All F60 qualifies as F51, but not the reverse. For new projects, specify F60 or dual-certified F60/F51.
What is the Maximum Operating Temperature for F60 Duplex Flanges?
315°C (600°F) as per ASME B16.5. This limit is metallurgical: 300–550°C causes 475°C embrittlement, while 600–1000°C promotes sigma phase. Both destroy toughness. Above 315°C, use austenitic grades (F316L, F321) or nickel alloys.
What Ferrite Content is Required in S32205 Duplex Flanges?
40–60% in the solution-annealed condition. Below 30% reduces SCC resistance; above 70% reduces toughness in reducing acids. Measured as per ASTM E562 or calibrated Feritscope. NORSOK M-630 projects often require 35–65% on both the forging body and the weld-affected zone.
Why Does ASTM A923 Testing Matter for Duplex S31803 Flanges?
ASTM A923 detects sigma and chi phases from improper heat treatment or excessive weld heat input. It includes three methods: Method A (NaOH etch) for visual detection, Method B (Charpy impact) to verify toughness, and Method C (ferric chloride test) to assess corrosion resistance. This testing is mandatory for critical oil & gas applications and for flanges governed by NORSOK specifications.
What Welding Filler Metal is Used for Duplex S31803 Flanges?
ER2209 (AWS A5.9) for GTAW and E2209 (AWS A5.4) for SMAW. The filler contains ~9% Ni (vs ~5% in base metal) to achieve 30–65% ferrite in weld metal. Use Ar + 2% N₂ for root passes. Heat input: 0.5–2.5 kJ/mm. Interpass: ≤150°C.
How Does Duplex 2205 Compare to Super Duplex 2507 for Flanges?
F53 (Super Duplex 2507) offers PREN ~42+ versus ~35 for F51/F60, with 550 MPa yield versus 450 MPa. However, F53 costs 40–60% more and is harder to weld. For most applications below 35°C, chloride exposure, F51/F60, performs adequately at a lower cost. Reserve F53 for hot seawater or aggressive chloride service.