Tesco Steel & Engineering manufactures ASTM A182 F22 long weld neck flanges — the rung that climbs both staircases: 2¼Cr-1Mo alloy steel, UNS K21590, Class 3 supply — with ASME B16.5 flange ends in Classes 150–2500 and the barrel made to order. The construction is the LWN's: the flange and the nozzle in one forging, one closing weld at the reactor, header or shell. The chemistry answers two questions at once: on the steam staircase it carries creep duty through the 550 °C class where F11's allowables taper; on the refinery side it is hydroprocessing's hydrogen-service workhorse — the 2¼Cr-1Mo of hydrocracker and hydrotreater walls, deep on the Nelson curves. The classic long-service caveat is handled openly below: temper embrittlement, managed by clean-heat chemistry and J-factor housekeeping. Certificate: 515/310 MPa, hardness 156–207 HB; welding sits between F11's and the 9-chrome rungs'. The climbs stay honest: F91 for 600 °C-class steam, F5/F9 when the enemy is sulphur. Facings: RF / FF / RTJ. Every lot with EN 10204 3.1/3.2 MTC. ISO 9001:2015, made in Mumbai, India — exported to 50+ countries.
ASTM A182 F22 Cl.3 · UNS K21590 · 1.7380 eq.Both Staircases — Steam Creep + HydrogenHydrocracker Country — The Nelson Curves515 / 310 MPa · 156–207 HBTemper Embrittlement — Handled OpenlyB16.5 Flange Ends · Class 150–2500Barrel: Length & Bore to OrderEN 10204 3.1 / 3.2 · ISO 9001:2015
ASTM A182 F22 Long Weld Neck Flanges — Specifications at a Glance
What is an ASTM A182 F22 Long Weld Neck Flange?
The dual citizen of the chrome-moly bench, in the nozzle pattern. An ASTM A182 F22 Class 3 flange (2¼Cr-1Mo, UNS K21590) whose neck continues as a long, heavy-walled straight barrel — the nozzle itself — bevelled for one closing butt weld at the reactor, header or shell. Steam: creep duty through the 550 °C class. Hydrogen: the hydroprocessing workhorse, deep on the Nelson curves — the chemistry hydrocracker walls are built from, with the nozzles to match. C 0.05–0.15% floor for the carbides; Cr 2.00–2.50%; Mo 0.87–1.13%. Supplied normalized & tempered (Class 3), 156–207 HB certified. Flange ends per ASME B16.5, Classes 150–2500; barrel length and bore stated by you. EN 10204 3.1 on every lot.
Also searched as: F22 LWN flange, 2.25Cr-1Mo long weld neck flange, P22-matching nozzle flange, A182 F22 Cl.3 RFLWN, K21590 LWN — all the same product. Related pages: the facings — LWNRF / LWNFF / LWNRTJ — the long weld neck hub, the F22 socketweld on small bore, the ladder — A105 / F11 / F5 / F9 / F91 — and the alloy steel hub.
The rule of the two staircases: steam creep climbs F11 → F22 → F91; sulphur climbs F5 → F9 — and F22 alone holds a rung on both: hydrogen-plus-creep is its private franchise.
What the 2¼ Chrome and the Full Moly Buy
The 550 °C-Class Steam Rung
Creep-rupture strength meaningfully beyond F11's — headers, drums and main-steam hardware where the first rung's allowables taper, on chemistry every boiler shop knows as P22's forged twin.
The Hydrogen Franchise
2¼Cr-1Mo sits high on the Nelson curves — Cr and Mo carbides refuse to feed hydrogen's methane attack, which is why hydrocrackers, hydrotreaters and ammonia loops are built from it, nozzles included.
A Stronger Certificate
Class 3's 515/310 MPa outruns F11 Cl.2's 485/275 — and the order book shows it: this is the rung where the 2500# heavy-barrel LWN is everyday hardware.
Honesty About the Long Years
Temper embrittlement is 2¼Cr-1Mo's classic caveat — managed, not feared: clean modern heats, J-factor chemistry on request, and the full story in the FAQ below.
Specification Notes — Getting F22 Long Weld Necks Right
Three honest notes.State the class: commerce and B16.5 ratings assume Class 3 (515/310, N&T) — Class 1 is the softer annealed variant and does not satisfy Class 3 allowables; the order line should say which. Name both enemies: design temperature and hydrogen partial pressure decide this rung — and when hot sulphur joins the hydrogen, the industry answer is an F22 pressure boundary with stainless overlay, or the F5/F9 staircase — say what the stream carries. And climb or descend by arithmetic:F11 serves the 500 °C class cheaper; F91's enhanced allowables rule the 600 °C class — F22 owns the band between and the hydrogen duty throughout.
How Our F22 LWN Flanges Are Manufactured
1
Forging — each piece individually forged from certified clean heats with the barrel integral — no welded build-ups — in any section up to the heaviest HB patterns.
2
Normalizing & tempering — the Class 3 N&T cycle that sets the tough tempered structure; furnace records retained against the heat number.
3
Hardness verification — every lot confirmed inside the 156–207 HB window: the floor proves the transformation, the ceiling protects welds and hydrogen duty.
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 — chemistry and mechanicals per heat; PMI-checked; J-factor computable from the certified analysis, low-tramp supply where specified; marked with grade, class, size, schedule and heat number.
6
Certification & packing — EN 10204 3.1 MTC with heat-treatment records (3.2 witnessed on request); chrome-moly WPS guidance included; faces and bevels protected, packed sea-worthy.
Where F22 LWN Flanges Are Used
Where the two staircases meet: hydrocracker and hydrotreater reactor-adjacent nozzles, hot hydrogen piping systems, ammonia and methanol synthesis loops, high-pressure heat-exchanger connections, supercritical and subcritical boiler headers, main-steam and hot-reheat hardware in the 550 °C class, and the instrument standpipes and level bridles that ride on all of them. Production and supply below:
Seven elements — temperature and hydrogen together confirm the rung:
1
Size & standard — e.g. 6″ NB ASME B16.5.
2
Pressure class & facing — 150#–2500#; RF, FF or RTJ with ring number — common in hydrogen service.
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 — ASTM A182 F22 Class 3 (Class 1 only if named); design temperature, hydrogen partial pressure and sulphur stated — they confirm F22 against F11 below, F91 above and the sulphur staircase sideways; J-factor / step-cooling requirements named where applicable.
6
Certification — EN 10204 3.1 with heat-treatment records (our standard) / 3.2 witnessed; hardness documentation where applicable.
Example: “LWN Flange RTJ, 4″ NB, ASME B16.5 Class 1500, R45 groove, barrel 300 mm, Sch 160 bore, heavy barrel, ASTM A182 F22 Cl.3, hydrotreater hot-separator nozzles — H2 120 bar at 400 °C, EN 10204 3.1 — 4 pcs.” Quotations normally within 24 hours with price, unit weight and delivery.
An ASTM A182 F22 long weld neck flange is a forged 2¼Cr-1Mo alloy steel flange — UNS K21590, supplied as Class 3 — 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 reactor, header or vessel shell. F22 is the chrome-moly bench's dual citizen: on the steam staircase it carries creep duty through the 550°C class where F11's allowables taper; on the refinery side it is hydroprocessing's hydrogen-service workhorse — the chemistry of hydrocracker and hydrotreater walls, deep on the Nelson curves. Flange ends follow ASME B16.5 in Classes 150 to 2500; the barrel is machined to the ordered length and bore. Supplied normalized and tempered with the 156-207 HB window certified.
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.
Why is F22 the grade that climbs both staircases?
Because 2¼% chromium with a full 1% molybdenum happens to answer two different questions well. On the steam staircase: the extra chromium and molybdenum over F11 buy meaningfully higher creep and stress-rupture strength, carrying headers, drums and main-steam hardware through the 550°C class that the first rung cannot hold. On the refinery staircase: the same chemistry sits far up the Nelson curves, making 2¼Cr-1Mo the defining material of high-temperature high-pressure hydrogen service — hydrocrackers, hydrotreaters and ammonia converters are built from it by the thousand tonnes, and their nozzles match. No other rung on the bench serves both worlds this way: F11 stops short on both counts, F5/F9 answer sulphur rather than hydrogen-plus-creep, and F91 is a steam specialist. That breadth is why F22 may be the most consequential chrome-moly of all.
What makes F22 the hydrogen-service workhorse?
The Nelson curves, which govern where each steel survives hot high-pressure hydrogen. Hydrogen attack works by diffusing into steel and reacting with carbides to form methane in internal voids — carbon steel succumbs at modest conditions, and each chromium-molybdenum step raises the survivable envelope because Cr and Mo carbides refuse to give up their carbon. The 2¼Cr-1Mo line sits high enough to enclose the operating windows of most hydroprocessing: hydrotreater and hydrocracker circuits, ammonia and methanol synthesis loops. That is why reactor shells are 2¼Cr-1Mo (often stainless-weld-overlaid for sulphur), why the hot hydrogen piping is P22, and why the LWN nozzles on that equipment forge in F22 — matched chemistry, matched welding, matched Nelson standing. State hydrogen partial pressure and temperature on the enquiry and the curve confirms the grade in minutes.
What is temper embrittlement — the classic 2¼Cr-1Mo caveat?
A slow, reversible loss of toughness that 2¼Cr-1Mo can suffer after years between roughly 370 and 565°C — exactly its service band — as tramp elements (phosphorus, tin, antimony, arsenic, with manganese and silicon assisting) migrate to grain boundaries. The industry learned this on hydrocracker walls decades ago and answered with chemistry housekeeping: modern clean steelmaking keeps the tramp levels low, purchasers of critical equipment specify composition factors (the J-factor and X-bar formulas) that cap the offenders, and operating practice warms heavy walls before pressurising. For flanges and nozzles the exposure is the same but the section thinner, so the issue is managed rather than feared: our F22 comes from clean modern heats, chemistry on the certificate lets any J-factor be computed, and low-tramp supply can be arranged where a project specifies limits. Awareness, not alarm — the grade's service record is superb.
What is the chemical composition of ASTM A182 F22?
Carbon 0.05-0.15% — the creep floor, set lower than F11's 0.10 — manganese 0.30-0.60%, silicon ≤0.50% (back to a simple cap: less silicon suits the hydrogen and embrittlement housekeeping), phosphorus ≤0.040%, sulphur ≤0.040%, chromium 2.00-2.50% and molybdenum 0.87-1.13% — the full 1% that does both the creep and the Nelson work. Seven specified elements, no nickel line. The recipe reads as the deliberate compromise it is: enough carbon for carbides, not so much as to harden welds; enough chromium for stability and hydrogen, molybdenum doubled over F11 for both missions. Chemistry is verified per heat, PMI-confirmed, and travels on the EN 10204 3.1 MTC — where a specification adds J-factor limits, the certificate documents compliance.
What are the mechanical properties of F22 long weld neck flanges?
Class 3, normalized and tempered: tensile strength 515 MPa (75 ksi) minimum, yield strength 310 MPa (45 ksi) minimum, elongation 20% minimum, hardness 156-207 HB — a genuinely stronger certificate than F11 Class 2's 485/275, befitting the heavier duty. As across the bench, the room-temperature numbers are the entry ticket rather than the mission: what F22 sells is the creep-rupture strength and hydrogen standing behind B16.5's alloy-group ratings, which carry its flanges deep into the 550°C class. The hardness window keeps its double duty — the floor certifying the transformation, the ceiling protecting welds — and the two-ceilings honesty applies: on a hot joint the gasket system and bolting retire long before the flange metal.
What is the difference between F22 Class 1 and Class 3?
Heat treatment and the certificate it produces, on identical chemistry. Class 3 — normalized and tempered, 515/310 MPa minimum — is the standard flange and forging supply, the strength B16.5 ratings assume, and what this page describes; write F22 with no class and Class 3 is what commerce delivers. Class 1 is the annealed, softer variant (415/205 minimum): maximum ductility and the easiest welding, occasionally specified for parts destined for severe cold forming or particular vessel-code paths, but rare in flange work. A Class 1 certificate does not satisfy a design rated on Class 3 allowables, so the class belongs on the order line. Our certificates state it explicitly either way.
How demanding is the welding on F22?
A step up from F11, comfortably short of the 9-chrome rungs — the middle of the bench's discipline. The steel air-hardens more decisively than 1¼Cr, so preheat runs typically 150-250°C and is held through welding; consumables are matching B3-class 2¼Cr-1Mo, low-hydrogen without exception; and PWHT sits around 675-750°C — hydrogen-service work often specifies the upper band with extended holds, since hardness limits and hydrogen duty reward thorough tempering. On coded hydroprocessing equipment, weld qualification commonly adds hardness surveys and, where clients specify it, step-cooling tests against temper embrittlement. None of this surprises a fabricator who lives in hydrocracker country — and the closing weld at the shell inherits exactly the practice the vessel itself was built with. 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.
What are standard, heavy-barrel and equal-barrel LWN flanges?
Three barrel weights for three duties. The standard LWN carries a barrel a little heavier than the matching pipe — the general-purpose vessel nozzle. The heavy-barrel (HB) pattern thickens the wall substantially — often approaching the hub section for its full length — for high-pressure nozzles, heavy nozzle loads and reinforcement-limited openings, where the extra metal does the area-replacement work the code asks of a vessel opening; hydroprocessing reactors and high-pressure headers are its natural home. The equal-barrel pattern keeps the barrel outside diameter equal to the hub for a clean cylindrical profile — favoured on manway and instrument connections. All three share B16.5 flange ends; the design calculation or the equipment drawing decides which is wanted.
When does F22 hand off — to F91, F11 or the sulphur rungs?
Three honest boundaries. Downward on the steam staircase: through the 500°C class F11 serves at lower cost, and below ~425°C carbon steel takes over entirely — F22 bought there is unused capability. Upward on steam: modern high-energy plants at 600°C-class conditions run on F91's enhanced allowables, which halve wall thicknesses at those temperatures; F22 remains the choice where conditions are moderate or where F91's exacting welding regime is unwelcome. Sideways: when the enemy is hot sulphur rather than hydrogen-plus-creep, the corrosion staircase answers — F5 and F9 carry sulphidation duty that F22's 2¼% chromium cannot; sour hydroprocessing service often pairs an F22 pressure boundary with stainless overlay for exactly this reason. State temperature, hydrogen and sulphur on the enquiry; the two staircases and our quotation pick the rung together.
What sizes and pressure classes do F22 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 F22 order book lives at the heavy end: hydroprocessing and synthesis-loop duty concentrates in Classes 900-2500 where heavy-barrel patterns dominate, while steam-side headers and drums use Classes 600-1500 — this is the rung where the 2500# heavy-barrel LWN is everyday hardware rather than an exception. 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 F22 LWN flange quotation?
Seven elements plus commercial terms: (1) size and dimensional standard — e.g. 6" NB ASME B16.5; (2) pressure class — 150 to 2500; (3) facing — RF (the default), FF or RTJ with ring number, RTJ being common in hydrogen service; (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 F22 Class 3 (Class 1 only if named) — with the service stated (design temperature, hydrogen partial pressure, sulphur) so the staircase rung is confirmed, and any J-factor or step-cooling requirements named; (7) certification — EN 10204 3.1 with heat-treatment records (our standard) or 3.2 witnessed, hardness documentation where applicable. Add quantity and destination; quotations normally within 24 hours.
Who manufactures ASTM A182 F22 long weld neck flanges in India?
Tesco Steel & Engineering is an ISO 9001:2015 certified flange manufacturer based in Mumbai, India, producing ASTM A182 F22 Class 3 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 clean heats, normalized and tempered with furnace records, hardness verified inside the 156-207 HB window, machined with the barrel bored to the ordered schedule or drawing, bevelled for the closing weld, PMI-checked, and marked with grade, class, size, schedule and heat number. Supplied with EN 10204 3.1/3.2 certification, J-factor documentation where specified, and chrome-moly WPS guidance — alongside the F11 rung below, F91 above, the F5/F9 refinery staircase and the complete LWN range. Exported to more than 50 countries.
