ASTM A182 F55 Long Weld Neck Flanges — Zeron 100 Type Super Duplex LWN Manufacturer
Tesco Steel & Engineering manufactures ASTM A182 F55 long weld neck flanges — super duplex UNS S32760, the Zeron 100 type, W.Nr. 1.4501 — with ASME B16.5 flange ends in Classes 150–2500 and the barrel made to order. The recipe reaches the seawater threshold by its own route: alongside 25% chromium, deliberate copper and tungsten at 0.50–1.00% each — tungsten as molybdenum's heavier cousin in the passive film, copper as margin where the seawater turns acidic — and, uniquely, a specification that guarantees PREN ≥40 as a certified number, computed with the tungsten term on every MTC. This is the North Sea heritage grade, and the LWN suits its culture: the projects that name S32760 are the ones that count welds — this forging deletes one from every nozzle, leaving one closing weld under S32760-matching procedure. Certificate: 750/550 MPa with a 25% ductility floor; solution annealed — no stress relief, ever; band −50 °C to 250–300 °C. The twins stay honest: F53/2507 is the same rung by a different recipe, F51 the economical rung below. Facings: RF / FF / RTJ; small bore on the F55 socketweld. Every lot with EN 10204 3.1/3.2 MTC and stated PREN, NACE MR0175 where specified. ISO 9001:2015, made in Mumbai, India — exported to 50+ countries.
ASTM A182 F55 · UNS S32760 · W.Nr. 1.4501Zeron 100 Type — Cu + W AlloyedPREN ≥40 — Guaranteed on Certificate750 / 550 MPa · 25% Ductility FloorNorth Sea Heritage — Welds CountedB16.5 Flange Ends · Class 150–2500Barrel: Length & Bore to OrderEN 10204 3.1 / 3.2 · NACE MR0175
ASTM A182 F55 Long Weld Neck Flanges — Specifications at a Glance
What is an ASTM A182 F55 Long Weld Neck Flange?
The Zeron 100 type, in the nozzle pattern. An ASTM A182 F55 flange (super duplex, UNS S32760) whose neck continues as a long, heavy-walled straight barrel — the nozzle itself — bevelled for one closing butt weld at the manifold, vessel or shell. Copper and tungsten alloyed at 0.50–1.00% each; PREN ≥40 guaranteed on the certificate via the tungsten-credited formula; 750/550 MPa with a 25% ductility floor. The North Sea heritage grade in the weld-counting construction: one forging, one closing weld, fewest initiation sites. C ≤0.030%; Cr 24.0–26.0%; Ni 6.0–8.0%; Mo 3.0–4.0%; N 0.20–0.30%. Supplied solution annealed with records — no stress relief, ever; band −50 °C to 250–300 °C. Flange ends per ASME B16.5, Classes 150–2500; barrel length and bore stated by you. EN 10204 3.1 with stated PREN on every lot.
Also searched as: F55 LWN flange, S32760 long weld neck flange, Zeron 100 LWN flange, super duplex nozzle flange, F55 RFLWN, guaranteed PREN LWN — all the same product. Related pages: the facings — LWNRF / LWNFF / LWNRTJ — the long weld neck hub, the F55 socketweld on small bore, the duplex family — F51 LWN / F53 LWN / duplex hub — and the seawater map's neighbours — 254 SMO / Monel / Inconel / Titanium.
The Chloride Ladder — Where the Twins Stand
Grade
PREN
The Rung
Page
316L
~24
Everyday stainless — chloride SCC risk above ~60 °C
The rule of the twins: same rung, two recipes — the specification's printed UNS number decides; F55's extras (copper, tungsten, the guaranteed PREN) matter most where the seawater turns acidic or the document demands the certified number.
What the Copper and Tungsten Buy
The Certified PREN — Not Merely Implied
PREN = %Cr + 3.3×(%Mo + 0.5×%W) + 16×%N ≥ 40, written into the specification — every heat demonstrates the number, and our MTCs state it explicitly; a piping class demanding ‘PREN ≥40 guaranteed’ is naming S32760 whether it says so or not.
Tungsten — Crevice Insurance Without the Sigma Tax
Molybdenum's heavier cousin in the passive film: it strengthens crevice resistance and earns its half-weight in the PREN formula without accelerating the intermetallic clock the way extra molybdenum would.
Copper — Margin Where the Sea Turns Acidic
Sulphuric-contaminated seawater, acidified wells, mineral-acid splash — the environments where plain super duplex sits closest to its limit are exactly where the copper earns its place in the recipe.
The Ductility Floor Engineers Quietly Prefer
25% elongation guaranteed against the twin's 15% — traded against a slightly lower tensile floor, on the same 550 MPa yield: a balance made for nozzle forgings that see field welding and bolting.
Specification Notes — Getting F55 Long Weld Necks Right
Three honest notes.The twins are chosen by the document: F55/S32760 and F53/2507 overlap almost completely — supply whichever UNS number the specification prints, and never let the two mix on a shelf (our PMI reads the Cu-W signature precisely so they cannot). No stress relief, ever: every soak in the intermediate band grows embrittling phases — solution anneal is the only reset, and residual-stress questions are answered by design and welding practice, not a furnace. And respect the walls: −50 °C cold, 250–300 °C hot — the copper and tungsten widen the corrosion envelope inside the band, they do not move the band; beyond it the nickel bench and titanium take over.
How Our F55 LWN Flanges Are Manufactured
1
Forging — each piece individually forged from certified S32760 heats with the barrel integral — no welded build-ups — in any section up to the heaviest HB patterns.
2
Solution annealing — the full-solution cycle and quench, the grade's only permissible heat treatment: intermetallics dissolved, balanced structure restored; furnace records retained per heat.
3
Verification — chemistry and mechanicals per heat; PREN computed with the tungsten term and stated on the certificate; ferrite measurement, impacts at MDT and pitting tests where the project's package calls them.
4
Machining — flange end to ASME B16.5; barrel turned to pattern (standard / HB / equal) and bored to the ordered schedule or drawing; RF serrations, flat face or RTJ groove per B16.20; weld end bevelled 37.5°.
5
Testing & marking — PMI reads the Cu-W signature on every piece, so F55 and F53 can never mix; NACE MR0175 documentation where sour service is specified; marked with grade, size, schedule and heat number.
6
Certification & packing — EN 10204 3.1 MTC with solution-anneal records and computed PREN (3.2 witnessed on request); super duplex WPS guidance included; faces and bevels protected, packed sea-worthy.
Where F55 LWN Flanges Are Used
Where the specification says S32760: North Sea and UK-heritage platform seawater systems, seawater lift and injection manifolds, firewater ring mains, chemical-injection and wellhead-adjacent connections, acidified-brine and sour-seawater duties where the copper earns its margin, desalination trains and FGD circuits written around the guaranteed PREN — and the separator, scrubber and exchanger nozzles that serve them all. Production and supply below:
Stainless Long Weld Necks — Machined at Our WorksLong Weld Neck — Heavy Barrel, Bevelled Weld End
F55 LWN Flange Dimensions
Flange-end dimensions are class-governed per ASME B16.5 (ratings per the super duplex material group); barrel length and bore per order. Full class-by-class charts:
Seven elements — the printed UNS number decides the twin, the test package completes the order:
1
Size & standard — e.g. 4″ NB ASME B16.5.
2
Pressure class & facing — 150#–2500#; RF, FF or RTJ with ring number — routine offshore.
3
Barrel length — overall, face to weld end: 150 / 230 / 300 mm stock or any stated length.
4
Barrel bore & pattern — pipe schedule to match or finished bore in mm; standard, heavy barrel or equal barrel; weld-end prep if non-standard.
5
Grade line, service & test package — ASTM A182 F55/S32760 (or F53 if the specification prints 2507); medium, chloride content and temperature stated; any PREN statement requirement named; pitting tests with method and temperature, impacts at MDT, ferrite measurement, NACE MR0175 where required.
6
Certification — EN 10204 3.1 with solution-anneal records and computed PREN (our standard) / 3.2 witnessed.
An ASTM A182 F55 long weld neck flange is a forged super duplex stainless steel flange — UNS S32760, the Zeron 100 type, W.Nr. 1.4501 — whose neck continues as a long, heavy-walled straight barrel that is itself the nozzle, bevelled at its far end for one closing butt weld made out at the manifold, vessel or exchanger shell. S32760 reaches the 40-PREN seawater threshold by a distinctive route: alongside 25% chromium, molybdenum and nitrogen, it deliberately alloys both copper and tungsten at 0.50-1.00% each — and uniquely, its specification guarantees PREN ≥40 as a certified number on every heat. 550 MPa yield with a 25% elongation floor. Flange ends follow ASME B16.5 in Classes 150 to 2500; the barrel is machined to the ordered length and bore. Supplied solution annealed with records — the only heat treatment the grade permits.
How does a long weld neck differ from a standard weld neck flange?
Geometry and mission. A standard weld neck's hub tapers quickly down to the pipe's outside diameter and wall, ending in a weld bevel a few centimetres from the flange face — it is built to butt-weld to pipe and continue as a piping run. A long weld neck keeps a full-section straight barrel for its entire length: no taper to pipe dimensions, wall far heavier than the matching schedule, length made to order. The mission follows the shape — the LWN is not a fitting on a pipe run but a nozzle in its own right, projecting through insulation, vessel walls or exchanger channels, with the butt weld relocated to the shell side where the fabricator wants it. In one certified forging it replaces the weld neck flange, the pipe nipple and one whole circumferential weld.
What makes F55 the 'Zeron 100 type' — what do the copper and tungsten do?
S32760 descends from Zeron 100, the super duplex developed in the UK with two deliberate additions its 2507 twin lacks. Tungsten behaves as molybdenum's heavier cousin in the passive film — it counts in the extended pitting formula and strengthens crevice resistance without accelerating the sigma-phase clock the way extra molybdenum would. Copper buys measurable margin in acidic environments — sulphuric-contaminated seawater, acidified wells, mineral-acid splash — where plain super duplex sits closer to its limit. The result is a grade with its own loyal following: North Sea and UK-heritage offshore specifications frequently name S32760 outright, and its certificate carries a feature no sibling offers — see the PREN question. In nozzle work the pedigree is felt directly: the platforms that write S32760 into their piping classes are the same ones that count welds, which is the LWN's whole argument.
Why is PREN guaranteed on an S32760 certificate?
Because the specification writes it in — uniquely among the common duplex grades. For most alloys PREN is something an engineer computes from the chemistry; for S32760 the requirement PREN = %Cr + 3.3×(%Mo + 0.5×%W) + 16×%N ≥ 40 is part of the material standard, so every certified heat must demonstrate the number, not merely imply it. Note the formula itself is the extended version crediting tungsten at half molybdenum's weight — the arithmetic recognition of what the tungsten addition does. For specifiers this is a genuinely useful property: a piping class written around 'PREN ≥40 guaranteed' is naming S32760 whether it says so or not, and our EN 10204 certificates state the computed PREN per heat explicitly.
Why does the LWN construction particularly suit seawater service?
Because seawater is the most relentless interrogator of welds and crevices in common service. Pitting and crevice attack initiate at heat-affected zones, weld toes and joint gaps — and offshore, every joint carries a second cost: subsea or splash-zone inspection for the life of the field. The long weld neck deletes one entire circumferential weld and its nipple from every nozzle: flange, neck and reinforcement arrive as one certified forging with one closing weld out at the shell, made once under qualified super duplex procedure, tested once, inspected once. Fewest initiation sites, fewest ferrite checks, least NDE, cleanest corrosion story — and on the North Sea projects where S32760 is the house grade, weld-count discipline has been written into the design culture for decades; the LWN is that culture in forged form.
What is the chemical composition of ASTM A182 F55 (UNS S32760)?
Carbon ≤0.030%, manganese ≤1.00%, silicon ≤1.00%, chromium 24.0-26.0%, nickel 6.0-8.0%, molybdenum 3.0-4.0%, nitrogen 0.20-0.30%, copper 0.50-1.00%, tungsten 0.50-1.00%, phosphorus ≤0.030%, sulphur ≤0.010%. Beside F53 the differences tell the design story: molybdenum trimmed to 3-4% and nitrogen to 0.20-0.30 — because tungsten picks up part of the pitting duty — while copper and tungsten appear as deliberate ranged additions rather than residual caps, and sulphur is held at the family's tightest ceiling. Chemistry is verified per heat, the PREN computed and stated, and PMI reads the Cu-W signature that distinguishes F55 from F53 on the shelf.
What are the mechanical properties of F55 long weld neck flanges?
In the solution-annealed condition A182 requires tensile strength 750 MPa (109 ksi) minimum, yield strength 550 MPa (80 ksi) minimum and elongation 25% minimum. Two comparisons worth making: the yield matches F53's 550 MPa exactly — the two super duplexes are interchangeable on strength, and both carry B16.5's super duplex ratings with margin — while the certificate trades a slightly lower tensile floor (750 against F53's 795) for a notably higher ductility floor (25% against 15%), a balance many piping engineers quietly prefer in a nozzle forging that will see field welding and bolting. In LWN duty the 550 MPa yield does what it does across the family: heavy-barrel area replacement with less metal, and the lightest compliant nozzle on weight-audited structures. Hardness sits within the duplex limits with NACE MR0175 documentation where sour service is specified.
F55 or F53 — how do I choose between the super duplex twins?
Nearly always by the specification, occasionally by the chemistry of the service. Their performance envelopes overlap almost completely: same 550 MPa yield, same 40-PREN seawater standing, same welding discipline and temperature band. F55's copper earns its margin where the seawater is acidified or the duty sees mineral-acid excursions; its tungsten adds crevice insurance; and its certificate carries the guaranteed PREN. F53 (2507) counters with the higher tensile floor and broader global stocking. In practice, North Sea and UK-heritage documents name S32760, Scandinavian and American ones lean 2507, and the correct answer is whichever UNS number your specification prints — we forge both LWN families, and the certificate matches the order exactly.
What are the temperature limits of S32760 — and why is stress relief prohibited?
The super duplex band: roughly -50°C to +250-300°C, with real walls on both sides. Cold: the ferrite half's ductile-brittle transition draws the line around -46 to -50°C, with impact testing at the minimum design temperature where projects approach it. Hot: at 25% chromium the intermetallic chemistry is eager — 475°C embrittlement and sigma phase both arrive faster than in standard duplex — so design codes cap sustained service around 250-300°C, and stress-relieving heat treatment is prohibited absolutely: every soak in the intermediate band grows embrittling phases, and only a full mill solution anneal resets the structure. The copper and tungsten additions do not move these walls meaningfully; they widen the corrosion envelope inside them. A specification pushing either wall gets an honest alloy change on our quotation — and residual-stress questions in fabrication are answered by design and welding practice, never by a furnace.
How is the closing weld on an F55 LWN made — the super duplex rules?
Under the same phase-balance discipline as all super duplex, with matching-composition consumables. No preheat beyond dryness and no PWHT ever; the craft is heat input — enough energy that the weld zone re-forms adequate austenite as it cools, not so much that sigma and nitrides precipitate — with interpass temperature capped around 100-150°C and filler of the over-alloyed S32760-matching type, so the joint inherits the copper-tungsten chemistry the piping class was written around. Nitrogen-bearing shielding protects the weld pool, and qualification on critical work adds ferrite measurement and pitting tests on the weldment, because a super duplex system is only as seawater-proof as its joints. The closing weld at the shell inherits the platform's own qualified procedure — and the LWN's gift is that there is only one such weld per nozzle. WPS guidance travels with every supply.
How are the barrel length and bore of a LWN specified?
Two numbers that belong on every enquiry. Length: measured overall from the flange face to the weld end — 150 mm (6"), 230 mm (9") and 300 mm (12") are the common stock lengths, and any length machines to order; state it explicitly, because 'long' is not a dimension. Bore: the barrel is drilled and bored to order — most commonly to match the inside diameter of the connecting pipe schedule, sometimes cylindrical special bores for level bridles, instrument standpipes or restriction work; state the schedule or the finished bore in millimetres. Add the weld-end preparation (standard 37.5° bevel unless told otherwise) and the nozzle is fully defined.
When does F55 hand off — on the seawater map?
Downward by economics: splash zones, brackish and produced water and most process chlorides are F51/2205's honest territory — a guaranteed-PREN super duplex there is qualification unused. Across by specification: F53 is the same rung by a different recipe, and the choice between the twins belongs to the document, not the salesman. Sideways by fabrication: seawater-class pitting resistance with fully austenitic fabricability is the 6Mo grade 254 SMO's offer. Upward when heat joins the chlorides: hot seawater with crevices and the hottest brines move to the nickel bench — Alloy 625's film-plus-muscle — and beyond it titanium opts out of the fight entirely. That is the seawater map this site keeps: copper-nickel's antifouling, Monel's nobility, 254 SMO's film, the super duplex twins' film-plus-strength, 625's film-plus-muscle, titanium's immunity — state medium, temperature, chloride and crevice geometry, and the map places the metal.
What sizes and pressure classes do F55 LWN flanges come in?
Flange ends follow ASME B16.5 from ½" to 24" NB in Classes 150, 300, 400, 600, 900, 1500 and 2500 — with the full class-by-class LWN dimension charts on this site — and larger diameters forge to order against B16.47 or drawing dimensions, with EN 1092-1 drilling machined on the same barrels. The F55 order book mirrors its North Sea habitat: seawater lift, firewater and utility systems run Classes 150-600, while injection manifolds, wellhead-adjacent connections and chemical-injection systems climb to 1500-2500, where the 550 MPa yield and heavy-barrel patterns work together. State size, class, barrel length and bore together — the four numbers define the forging — and our quotation returns price, unit weight and delivery per class.
What details are needed to get an accurate F55 LWN flange quotation?
Seven elements plus commercial terms: (1) size and dimensional standard — e.g. 4" NB ASME B16.5; (2) pressure class — 150 to 2500; (3) facing — RF (the default), FF or RTJ with ring number, RTJ being routine offshore; (4) barrel length overall, face to weld end — 150/230/300 mm stock or any stated length; (5) barrel bore — pipe schedule to be matched or finished bore in millimetres, with pattern (standard, heavy barrel, equal barrel) and weld-end prep if non-standard; (6) the grade line — ASTM A182 F55/S32760, or F53 if your specification names 2507 — with the service stated (medium, chloride content, temperature), any PREN statement requirement named, and the project's test package: pitting tests with method and temperature, impacts at minimum design temperature, ferrite measurement, NACE MR0175 for sour service; (7) certification — EN 10204 3.1 with solution-anneal records and computed PREN (our standard) or 3.2 witnessed. Add quantity and destination; quotations normally within 24 hours.
Who manufactures ASTM A182 F55 long weld neck flanges in India?
Tesco Steel & Engineering is an ISO 9001:2015 certified flange manufacturer based in Mumbai, India, producing ASTM A182 F55 super duplex long weld neck flanges with B16.5 flange ends from ½" to 24" NB (larger to order) in Classes 150-2500, in standard, heavy-barrel and equal-barrel patterns — each forged individually from certified heats, solution annealed with furnace records retained, machined with the barrel bored to the ordered schedule or drawing, bevelled for the closing weld, PMI-checked with the Cu-W signature read so F55 and F53 can never mix, and marked with grade, size, schedule and heat number. Supplied with EN 10204 3.1/3.2 certification including the computed PREN, NACE MR0175 declaration where specified, and super duplex WPS guidance — alongside the F51 and F53 LWN rungs, the seawater map's nickel and titanium benches, and the complete long weld neck range. Exported to more than 50 countries.
