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Duplex Steel UNS S31803 / S32205 Fasteners Supplier in Mumbai, India
Nicorex Alloys is an ISO 9001 and ISO 14001 certified supplier, importer, stockist, and trading company of Duplex 2205 fasteners in Mumbai, India. All stock is dual-certified S32205/S31803 with 40–60% ferrite content verified as per ASTM E562.
S32205 (A182 F60), introduced in 1996, consists of Cr (≥22.0%), Mo (≥3.0%), and N (≥0.14%), guaranteeing minimum PREN ≥34.1. S31803 (ASTM A182 F51) was the original Duplex 2205 designation that comprises Cr (21.0%), Mo (2.5%), and N (0.08%), guaranteeing minimum PREN ≥30.5. A182 F60 tightens the minimums for Cr, Mo, and N, providing higher, more consistent corrosion resistance, improved microstructural stability, and better performance in severe environments. S32205 always satisfies the requirements for S31803 and can therefore be dual-certified as S32205/S31803. Werkstoff 1.4462, SAF 2205, and EN X2CrNiMoN22-5-3 all refer to this alloy. Duplex 2205 fasteners deliver a high yield strength (450 MPa) with superior chloride corrosion resistance (PREN 34–36).
At Nicorex Alloys, we stock Duplex steel UNS S31803/S32205 fasteners in types like hex bolts, heavy hex bolts, stud bolts, socket head cap screws, hex nuts, heavy hex nuts, lock nuts, flat washers, spring washers, threaded rods, U-bolts, anchor bolts, eye bolts, and set screws. Sizes of these fasteners range from M6–M100 / 1/4”–4”. Standards include ASTM A1082 (dedicated duplex bolting), A479 (bar), A182 F51/F60, NACE MR0175/ISO 15156, NORSOK MDS D45. Service range is from −50°C to +315°C (600°F).
Duplex S31803 and S32205 Fastener Specifications
Duplex S31803 fastener specifications, including standards, diameters, and conditions, are explained in the table below:
| Parameter | Details |
|---|---|
| Bolting Spec (Dedicated) | ASTM A1082 / A1082M |
| Bar Stock | ASTM A479 / A276 S31803 / S32205 |
| Forging Spec | ASTM A182 F51 (S31803) / F60 (S32205) |
| Diameter | M6 – M100 / 1/4” – 4” |
| Condition | Solution Annealed ONLY (≥1020°C, water quench) |
Note: ASTM A193 does NOT have a Duplex 2205 grade. For duplex bolting, specify A1082 or A479.
Chemical Composition of ASTM A182 F51 and F60 Fasteners
The chemical compositions of F51 (S31803) and F60 (S32205), as per ASTM A182, are covered in the table below:
| Grade | Carbon (C) | Chromium (Cr) | Nickel (Ni) | Molybdenum (Mo) | Nitrogen (N) | Iron (Fe) |
|---|---|---|---|---|---|---|
| F51 / S31803 | ≤0.030 | 21.0–23.0 | 4.5–6.5 | 2.5–3.5 | 0.08–0.20 | Balance |
| F60 / S32205 | ≤0.030 | 22.0–23.0 | 4.5–6.5 | 3.0–3.5 | 0.14–0.20 | Balance |
The three tighter F60 limits (Cr, Mo, N) are the exact elements in the PREN formula: %Cr + 3.3×%Mo + 16×%N. F60 minimum PREN = 34.14. F51 minimum PREN = 30.53. In borderline chloride environments, this ~4-point gap determines whether fasteners pass or fail ASTM G48 pitting tests. Nitrogen stabilises austenite in the weld HAZ and prevents sigma phase. Always specify S32205/F60 for new projects.
Mechanical Properties of Duplex Steel F51 and F60 Fasteners
As per ASTM A182, the mechanical properties of Suplex steel F51 and F60, in the solution annealed condition, are provided below:
| Grade | Tensile (min) | Yield 0.2% (min) | Elongation (min) | Reduction of Area (min) | Hardness (A1082) |
|---|---|---|---|---|---|
| F51 (S31803) | 620 MPa (90 ksi) | 450 MPa (65 ksi) | 25% | 45% | 293 HBN / 31 HRC max |
| F60 (S32205) | 655 MPa (95 ksi) | 450 MPa (65 ksi) | 25% | 45% | 293 HBN / 31 HRC max |
Equivalent Grades of Duplex S31803 / S32205 Fasteners
The international equivalent designations, across UNS, Werkstoff, and other designations, are mentioned in the table below:
| UNS | Werkstoff | EN | JIS | GOST |
|---|---|---|---|---|
| S31803 (legacy) / S32205 (preferred) | 1.4462 | X2CrNiMoN22-5-3 | NW 2201 | НП-2 |
Get Duplex S31803 and S32205 Fasteners at Competitive Prices
Types of Duplex S31803 and S32205 Fasteners
At Nicorex Alloys, we stock the following 10 types of Suplex S31803 and S32205 fasteners:
Duplex Steel S31803 Hex Bolts
Duplex Steel S32205 Stud Bolts
DSS 31803 Socket Head Cap Screws
DSS 32205 Hex Nuts
UNS S31803 Lock Nuts
UNS S32205 Flat Washers
F51 Threaded Rods
F60 U-Bolts
Duplex Steel S31803 Set Screws
Duplex Steel S32205 Eye Bolts
Solution anneal: 1020–1080°C followed by rapid water quench to maintain ~50/50 ferrite-austenite balance. This is the ONLY acceptable condition. Do NOT accept aged, cold-worked-only, or stress-relieved duplex fasteners for corrosion service. Inadequate quenching causes sigma phase precipitation, destroying toughness and corrosion resistance.
Surface Finish and Coating Options for Duplex 2205 Fasteners
Standard options include plain/self-colour (inherent Cr₂O₃ passivation), acid passivated as per ASTM A967, PTFE/Xylan coated threads (anti-galling), manganese phosphate (thread lubrication), and silver/nickel plated. Hot-dip galvanising is NOT recommended: the ~450°C process temperature causes 475°C embrittlement.
Galling warning: Duplex steels work-harden rapidly during assembly, making them highly susceptible to thread galling. Always use nickel-based or PTFE-based anti-seize (never copper-based), control tightening speed, and specify PTFE-coated threads on the purchase order.
Industries and Applications for Duplex S31803 / S32205 Fasteners
Duplex S31803/S32205 is specified in the following 8 applications:
- Topside process piping flange bolting, production separator vessel studs, wellhead tree fasteners, sour gas gathering systems (NACE MR0175). F60 preferred for new projects.
- RO membrane housing bolting, high-pressure pump studs, intake piping flanges, and brine heater flange bolts.
- Reactor vessel studs, heat exchanger bolting in chloride service, FGD scrubber bolting, and ethylene oxide plant flange studs.
- Digester bolting, bleach plant fasteners in ClO₂ environments.
- Seawater piping flange studs, ballast system fasteners, and cargo tank bolting. Classification societies (DNV, Lloyds, ABS, BV) approve Duplex 2205 for seawater systems.
- FGD scrubber fasteners, cooling tower hardware, and condenser tubesheet bolting.
- Processing equipment bolting, where chloride cleaning agents cause SCC in 316L.
- Bridge, tunnel, and coastal structure connections. Stonecutters Bridge (Hong Kong) and Oresund Bridge use Duplex 2205 structural components.
How to Order Duplex S31803 and S32205 Fasteners From Nicorex Alloys
Provide the following documents to place an order for Duplex S31803 and S32205 fasteners:
- Fastener Type — Stud Bolts / Hex Bolts / Heavy Hex Nuts / Washers / Threaded Rods
- Size — Diameter x Length (M8–M72 / ¼"–4") — specify thread type (UNC / UNF / Metric)
- Thread Tolerance — 6g / 6H (Metric) / 2A / 2B (Inch) — specify fit class
- Material Grade — S31803 / UNS S31803 / F51 or S32205 / UNS S32205 / W.Nr. 1.4462 / F60
- Quantity — Number of pieces, sets, or weight in kg
- Standard — ASTM A182 / ASME SA182, ASME B18.2.1, ASME B18.2.2, ASME B16.5
- Documentation — MTC 3.1/3.2, PMI, FN Report, Hardness Certificate, TPI Certificate
- Packaging — Polybag per piece, ISPM 15 compliant export cartons with full labelling
- Delivery — Domestic / International (specify destination)
Frequently Asked Questions
What is the Difference Between S31803 and S32205 Duplex Fasteners?
Both are Duplex 2205 (Werkstoff 1.4462). S32205 (F60) has tighter minimums: Cr ≥22.0% (vs 21.0%), Mo ≥3.0% (vs 2.5%), N ≥0.14% (vs 0.08%). This guarantees PREN ≥34.1 vs potentially ~30.5 for bottom-of-spec S31803 (F51). F60 tensile: 655 MPa vs 620 MPa for F51. S32205 always meets S31803 (dual certification) but not vice versa.
What is the Maximum Service Temperature for Duplex S31803 Bolting?
315°C (600°F) as per ASME B31.3. Above ~300°C, alpha-prime / 475°C embrittlement causes irreversible toughness loss. Sigma phase forms at 600–900°C.
Is Duplex S32205 Magnetic?
Yes, partially. Duplex 2205 contains ~50% ferrite, which is ferromagnetic. The magnetic response distinguishes duplex from austenitic grades (316L, 304) and is useful for field PMI.