UNS NO32760 (F55) Pipe Fittings
UNS S32760, also designated F55, is a high‑performance super‑duplex stainless steel alloy known for both excellent corrosion resistance and high mechanical strength. Rose Metal Industries, acting as manufacturer, stockist, and exporter, supplies pipe fittings made from F55 to clients across Tamil Nadu, Andhra Pradesh, Karnataka, Telangana, Puducherry (Pondicherry), Andaman & Nicobar Islands — as well as to global markets. These pipe fittings are especially suited for chemically aggressive, offshore, marine, and high‑pressure applications, where durability and resistance to environmental degradation are critical..
UNS S32760, commonly known as F55, is a high-performance super-duplex stainless steel alloy renowned for its exceptional corrosion resistance and superior mechanical strength. Rose Metal Industries is a leading manufacturer, stockist, and exporter of F55 pipe fittings, serving industries across Tamil Nadu, Andhra Pradesh, Karnataka, Telangana, Puducherry (Pondicherry), and the Andaman & Nicobar Islands, as well as international markets. These fittings are ideal for aggressive environments where both durability and resistance to environmental degradation are critical.
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The chemical composition of F55 pipe fittings includes approximately 24–26% Chromium (Cr), 6–8% Nickel (Ni), 3–4% Molybdenum (Mo), and Nitrogen (N) around 0.20–0.30%, with trace elements of Copper and Tungsten to further enhance pitting and crevice corrosion resistance. The low carbon content (≤0.03%) minimizes carbide precipitation and ensures long-term corrosion protection. This duplex microstructure, consisting of roughly equal parts austenite and ferrite, provides outstanding resistance to chloride stress corrosion cracking (SCC) and localized corrosion in seawater and chemical process environments.
Mechanically, F55 pipe fittings exhibit high strength and toughness, with typical yield strength around 550 MPa and tensile strength ranging from 750–800 MPa, depending on the product form. Elongation values are generally 25% or more, offering excellent ductility for forming, welding, and installation. These properties make F55 fittings ideal for high-pressure and high-stress applications where long-term reliability is essential..
Specifications & Standards
| Property | Typical / Standard |
|---|---|
| Grade | UNS S32760 (F55) — Super Duplex Stainless Steel |
| Common Standards | ASTM A815 / ASME SA815 (wrought butt-weld fittings), ASTM A182 / ASME SA182 (forged fittings), EN equivalents |
| Fitting Types | Butt-weld elbows, tees, reducers, caps, forged socket-weld & threaded fittings, flanges |
| Forms & Finishes | Hot-formed, forged, machined, pickled, polished |
| Quality & Testing | MTC (EN-3.1 / 3.2 on request), PMI, NDT, dimensional & mechanical tests |
Chemical Composition (typical ranges, wt %)
| Element | Typical (F55) |
|---|---|
| Chromium (Cr) | 24.0 – 26.0 |
| Nickel (Ni) | 6.0 – 8.0 |
| Molybdenum (Mo) | 3.0 – 4.0 |
| Nitrogen (N) | 0.20 – 0.30 |
| Carbon (C) | ≤ 0.03 |
| Copper (Cu) | ≈ 0.5 – 1.0 (may be present) |
| Tungsten (W) | ≈ 0.2 – 1.0 (where specified) |
| Iron (Fe) | Balance |
Mechanical Properties (typical — solution annealed)
| Property | Typical Value | Notes |
|---|---|---|
| Yield Strength (0.2% proof) | ≈ 550 MPa | Depends on fitting geometry |
| Tensile Strength (UTS) | ≈ 750 – 900 MPa | Section & processing dependent |
| Elongation | ≥ 20 – 25% | Good ductility for forming/welding |
| Hardness | BHN / HB 270 – 310 | Typical duplex range |
Equivalent Grades & Designations
| Standard System | Designation |
|---|---|
| UNS | S32760 |
| EN / DIN | 1.4501 (or X2CrNiMoCuWN25-7-4 variants depending on spec) |
| ASTM / ASME | F55 / commonly used under ASTM A815 (buttweld), A182 (forged) |
| Trade Name | Super Duplex F55 / Super Duplex 32760 |
Dimension Chart — Typical Fitting Coverage
Common commercial coverage — custom sizes and schedules available on request.
| Fitting Type | Size Range (NB) | Wall / Schedule |
|---|---|---|
| Butt-weld elbows, tees, reducers | ½" – 24" (15 – 600 mm) | SCH 5S, 10S, 40, 80, XS, XXS, custom |
| Forged socket-weld / threaded fittings | ⅛" – 4" (6 – 100 mm) | AS per ASME / custom |
| Flanges | ½" – 24" (15 – 600 mm) | Raised face, RTJ, slip-on, weld neck — per ASME B16.5/16.47 |
Typical Applications
- Offshore & subsea pipeline systems, topside process piping and manifolds
- Chemical & petrochemical process lines handling chlorides, acids and halides
- Desalination plants, seawater cooling systems and brine handling
- Marine systems, shipbuilding, ballast, cooling and deck piping
- Power generation — cooling water, heat exchangers, condensers
- High-pressure, high-temperature and high-cycle industrial piping
WRose Metal Industries supplies F55 pipe fittings in various forms, including buttweld fittings, forged fittings (socket-weld, threaded), elbows, tees, reducers, and flanges. These fittings comply with standards such as ASTM A815 / ASME SA815 for buttweld types and ASTM A182 / ASME SA182 for forged fittings. Sizes range from 1/2″ NB to 24″ NB for seamless and welded butt-weld fittings, and from 1/8″ NB to 4″ NB for socket-weld or threaded forged fittings, covering multiple schedules from SCH 5s to XXS/custom..
F55 pipe fittings are widely applied in offshore oil and gas, chemical processing, desalination plants, power generation, marine industries, and high-pressure industrial piping systems. They are particularly chosen for environments exposed to chlorides, seawater, acids, or alkalis, where conventional austenitic or duplex stainless steels would be less reliable. The combination of high corrosion resistance, strength, and fatigue resistance ensures minimal maintenance and long service life.
Frequently Asked Questions (FAQ)
Q1: Why choose UNS S32760 (F55) pipe fittings over standard stainless fittings?
A: F55 (S32760) fittings deliver much higher pitting/crevice resistance and strength than common austenitic grades (304/316) and even standard duplex grades — making them ideal for chloride-rich and high-pressure environments.
Q2: What standards do your F55 fittings comply with?
A: We supply fittings to ASTM A815 / ASME SA815 (wrought butt-weld), ASTM A182 (forged) and other customer-specified standards. EN equivalents can be supplied where required.
Q3: Do you provide Mill Test Certificates (MTC) and third-party inspection?
A: Yes — Rose Metal Industries issues MTCs (EN 10204 3.1/3.2 on request), performs PMI, NDT, and can arrange third-party inspection and customized documentation for export projects.
Q4: Can you supply custom sizes, schedules and special finishes?
A: Yes — we offer cut-to-order, custom schedules, special machining, anti-corrosion finishes, and packaging for both domestic projects (Tamil Nadu, Andhra Pradesh, Karnataka, Telangana, Puducherry, Andaman & Nicobar Islands) and international export orders.
Q5: Which industries most commonly use F55 fittings?
A: Offshore oil & gas, petrochemical & chemical processing, desalination, marine & shipbuilding, power generation and any industry where chloride exposure, high pressure, or high cycle loading demand superior materials.