Incoloy 800 Long Weld Neck Flanges — UNS N08800 Iron-Nickel-Chromium LWN Manufacturer
Tesco Steel & Engineering manufactures Incoloy 800 long weld neck flanges — the bridge alloy between this site's two great benches: ASTM B564, UNS N08800, W.Nr. 1.4876, X10NiCrAlTi32-20 — with ASME B16.5 flange ends in Classes 150–2500 and the barrel made to order. The design stands deliberately in the middle: iron at a ≥39.5% floor — the only deliberate iron floor on the bench, keeping stainless economics and even a steel-series Werkstoff number — while 30–35% nickel crosses the threshold that matters: chloride-SCC immunity and structural stability. This page heads the 800/800H/800HT family — the carbon-floor thread the stainless H-grades began lands here, with the controlled-carbon siblings holding the code-creep certificates of reformer and furnace service. Two threads close honestly: the massive-nickel SCC route bought at bridge prices, and the sulphidising reversal — the iron-based rung that outlasts the nickel summit in sulphur-bearing gas, exactly as the 601 page conceded. Hand-offs: 310S below, 600/625 across, 800H/800HT up for rated creep. One forging, one closing weld with ERNiCr-3. Facings: RF / FF / RTJ; small bore on the Incoloy 800 socketweld. Every lot with EN 10204 3.1/3.2 MTC. ISO 9001:2015, made in Mumbai, India — exported to 50+ countries.
ASTM B564 · UNS N08800 · W.Nr. 1.4876X10NiCrAlTi32-20 — The Bridge AlloyFe ≥39.5% Floor · Ni 30–35%Chloride-SCC Immune at Bridge PricesHeads the 800 / 800H / 800HT Family520 / 205 MPa AnnealedB16.5 Flange Ends · Class 150–2500EN 10204 3.1 / 3.2 · ISO 9001:2015
Incoloy 800 Long Weld Neck Flanges — Specifications at a Glance
What is an Incoloy 800 Long Weld Neck Flange?
The bridge alloy, in the nozzle pattern. An Incoloy 800 flange (UNS N08800, ASTM B564) whose neck continues as a long, heavy-walled straight barrel — the nozzle itself — bevelled for one closing butt weld at the exchanger, heater or vessel shell. Iron at a ≥39.5% floor for stainless economics; 30–35% nickel for SCC immunity and stability; 19–23% chromium for the film — and the head of the 800/800H/800HT family, whose controlled-carbon siblings hold the code-creep certificates. Welds with ERNiCr-3, no PWHT. Supplied annealed — 520/205/30, fine-grained for aqueous duty. Flange ends per ASME B16.5, Classes 150–2500; barrel length and bore stated by you. EN 10204 3.1 on every lot.
Fine-grained standard grade: aqueous duty, moderate heat, general service
Incoloy 800H
N08810
0.05–0.10% — the carbon floor
Coarse-grain anneal — the code-creep certificates of rated hot pressure parts
Incoloy 800HT
N08811
0.06–0.10% + Al+Ti 0.85–1.20%
The tightened chemistry — the family's highest creep certificates
The thread closes: the 304H and 316H pages told the carbon-floor story in miniature — this is the family that made it famous: below the creep range plain 800 serves; rated duty names H or HT, and the certificate, not the label, is the guarantee.
What the Bridge Position Buys
SCC Immunity at Bridge Prices
30–35% nickel crosses the immunity threshold — the massive-nickel route of the site's SCC story, bought with an iron floor keeping the economics closer to stainless than to nickel alloy.
The Sulphidising Reversal
In reducing sulphur-bearing gas the iron floor dilutes the nickel-sulphur eutectic — the 800 family stands where 600 and 601 corrode, exactly the concession the 601 page made.
Head of the Creep Family
The 800H/800HT siblings hold ASME code-creep certificates for reformer and furnace pressure parts — one family, three chemistries, ordered by the grade line.
Stable Between Two Worlds
Fully austenitic from cryogenic up, no sigma anxiety, carburising and nitriding standing — one alloy serving hot gas on one side of an exchanger and hot water on the other.
Specification Notes — Getting Incoloy 800 Long Weld Necks Right
Three honest notes.This page is plain 800: rated creep duty above ~600 °C belongs to 800H or 800HT by name — the certificate, not the label, is the guarantee, and we quote the sibling (or dual-certified material) whenever the duty shows it. Do not pay the bridge premium without its virtues: steady oxidation with no SCC exposure reads 310S below at stainless prices. And the bridge is not a wet-severity alloy: its aqueous credential is stability and SCC immunity, not high-PREN pitting resistance — hot chloride pitting duty reads the duplex ladder or 625, honestly.
How Our Incoloy 800 LWN Flanges Are Manufactured
1
Forging — each piece individually forged from certified N08800 heats (800H/800HT to their own specifications) kept segregated on the alloy shelf, with the barrel integral — no welded build-ups.
2
Annealing — fine-grained for plain 800; the coarse-grain creep anneals belong to the H/HT siblings; records retained against the heat number.
3
Verification — chemistry per heat with the iron floor, nickel window and Al/Ti doses certified; mechanicals per heat at the 520/205 line.
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 iron-nickel-chromium signature on every piece — the balance separating the 800 family from both the stainless shelf and the Inconel bins; marked with grade, size, schedule and heat number.
6
Certification & packing — EN 10204 3.1 MTC (3.2 witnessed on request); WPS guidance naming the ERNiCr-3 filler; faces and bevels protected, packed sea-worthy.
Where Incoloy 800 LWN Flanges Are Used
Where heat and water meet: steam reformer and cracker outlet systems and their exchanger nozzles (creep-rated positions in H/HT, cooler positions in plain 800), process heaters, carburising and nitriding atmospheres, feedwater heaters and chloride-touched steam systems where SCC immunity retires stainless, moderate-band furnace duty — including the sulphur-bearing atmospheres where the iron floor outlasts the nickel bench — and the vessel nozzles, standpipes and level bridles riding on all of them. One forging, one closing weld. Production and supply below:
Long Weld Necks — Machined at Our WorksLong Weld Neck — Heavy Barrel, Bevelled Weld EndDN600 RF Long Weld Neck — Large Diameter, B16.5 Drilling
Incoloy 800 LWN Flange Dimensions
Flange-end dimensions are class-governed per ASME B16.5 (ratings per the alloy's tables — checked at service temperature); barrel length and bore per order. Full class-by-class charts:
Seven elements — the grade line and the temperature decide the family member:
1
Size & standard — e.g. 6″ NB ASME B16.5.
2
Pressure class & facing — 150#–2500#, checked against the derating tables at service temperature; RF, FF or RTJ with ring number.
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 & duty — ASTM B564 Incoloy 800 (UNS N08800) — with 800H / 800HT named for rated creep service (dual-certified where marginal) and the duty stated fully: temperature, chemistry, atmosphere — checking 310S below and 600/625 across.
6
Certification — EN 10204 3.1 (our standard) / 3.2 witnessed.
Example: “LWN Flange RF, 8″ NB, ASME B16.5 Class 300, barrel 230 mm, Sch 40 bore, standard pattern, ASTM B564 Incoloy 800 UNS N08800, feedwater heater nozzles — chloride-touched steam at 280 °C, EN 10204 3.1 — 6 pcs.” Quotations normally within 24 hours with price, unit weight and delivery.
An Incoloy 800 long weld neck flange is a forged iron-nickel-chromium alloy flange — UNS N08800, W.Nr. 1.4876, X10NiCrAlTi32-20, supplied to ASTM B564 — 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 exchanger, heater or vessel shell. Incoloy 800 is the bridge alloy between the stainless and nickel benches: iron at a deliberate ≥39.5% floor keeps stainless-familiar structure and economics, while 30-35% nickel buys chloride-SCC immunity and structural stability, and 19-23% chromium forms the film. It heads the 800/800H/800HT family whose controlled-carbon siblings hold the code-creep certificates. Flange ends follow ASME B16.5 in Classes 150 to 2500; the barrel is machined to the ordered length and bore. Supplied annealed at 520/205 MPa with EN 10204 3.1/3.2 certification.
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 Incoloy 800 called the bridge alloy — and why does iron have a floor?
Because it stands deliberately between the two benches this site has built. From the stainless side: iron is specified at a floor of 39.5% — the only deliberate iron floor on the whole LWN series — keeping the austenitic structure familiar, the economics closer to stainless than to nickel alloy, and even the Werkstoff number in the steel series: 1.4876, where every Inconel and Monel carries a 2-series number. From the nickel side: 30-35% nickel is exactly enough to cross the threshold that matters — chloride stress corrosion cracking immunity, the third route the 904L page named — and to hold the structure stable through heat that destabilises leaner austenitics. The chromium at 19-23% forms a film a step deeper than 304's. The result is the engineer's middle answer: when 310S lacks the SCC immunity and stability, and 600 costs more nickel than the duty needs, the bridge carries it — which is why reformer and exchanger specifications write the 800 family by habit.
What is the 800 / 800H / 800HT family — the carbon floor's last chapter?
The thread this site's stainless H-grades began, finished on the alloy that made it famous. Plain 800 — this page — caps carbon at 0.10% with no minimum and is supplied fine-grained: the right structure for aqueous duty, moderate heat and general service. 800H (UNS N08810) writes the carbon floor: 0.05-0.10% guaranteed, with a coarse-grain anneal — the combination that buys code-recognised creep strength, exactly as the 304H and 316H pages described in miniature. 800HT (UNS N08811) tightens further: carbon 0.06-0.10% plus an aggregate aluminium-titanium window of 0.85-1.20%, buying the highest creep certificates of the family. The practical rules mirror the stainless bench's: below the creep range, plain 800 serves and is standard; rated hot pressure parts specify H or HT by name and the certificate — not the label — is the guarantee; and dual-certified material resolves marginal cases. We supply all three against their own specifications — state the grade line, and the paperwork follows it.
What do the small aluminium and titanium doses do?
Housekeeping, not hardening — and the distinction places the alloy on the bench correctly. At 0.15-0.60% each, the aluminium and titanium are dosed an order below K-500's age-hardening levels and below 601's alumina-scale dose: their job is to tie up carbon and nitrogen, deoxidise the melt and steady the austenitic structure through long heat — quiet stabilisation chemistry in the spirit of the stainless bench's locks, not a strengthening mechanism. That said, the doses matter enough to specify: in 800HT the aggregate Al+Ti window of 0.85-1.20% is deliberately raised and tightened, because at creep temperatures those elements' fine precipitates contribute measurably to rupture strength — the one member of the family where the housekeeping earns a strengthening role. On plain 800 the reading is simple: a clean, stable, weldable matrix with nothing waiting to age, which is exactly what the closing-weld FAQ relies on.
What is the chemical composition of Incoloy 800 (UNS N08800)?
Nickel 30.0-35.0%, chromium 19.0-23.0%, iron ≥39.5% — a floor, not a cap — carbon ≤0.10%, aluminium 0.15-0.60% and titanium 0.15-0.60%, manganese ≤1.50%, silicon ≤1.0%, copper ≤0.75%, sulphur ≤0.015%. The aluminium and titanium are dosed small — enough to tie up carbon and nitrogen and steady the structure, not the hardening doses of the age-hardened alloys. Note what the carbon cap means: plain 800 keeps carbon at or below 0.10% with no minimum — the controlled-carbon creep grades 800H (0.05-0.10%) and 800HT (0.06-0.10% with tightened Al+Ti) are separate specifications, and the difference decides high-temperature service. Chemistry is verified per heat, PMI-confirmed on the iron-nickel-chromium signature — the balance that separates the 800 family from both the stainless shelf and the Inconel bins — and travels on the EN 10204 3.1 MTC.
What are the mechanical properties of Incoloy 800 long weld neck flanges?
Annealed to ASTM B564: tensile strength 520 MPa (75 ksi) minimum, yield strength 205 MPa (30 ksi) minimum, elongation 30% minimum — stainless-familiar numbers from a stainless-familiar structure, fully austenitic and tough from cryogenic temperatures up. Standard-grade 800 is supplied fine-grained, which serves aqueous and moderate-heat duty with the best short-term strength and corrosion surface; the coarse-grain anneals belong to the H and HT siblings, whose creep certificates need them. For nozzle duty the frame is the bench's usual one: flange geometry is class-governed, ratings follow B16.5's tables for the alloy — checked at service temperature — and the heavy LWN barrel adds stiffness where nozzle loads bear. The honest boundary repeats the family FAQ's: plain 800's numbers are room-and-warm-service numbers, and rated creep duty above roughly 600°C belongs to 800H/800HT by specification, not to this page's certificate.
What is the ASTM B564 specification for Incoloy 800 flanges?
The nickel bench's shared forging standard, in the chapter where it reaches back toward iron. ASTM B564 (ASME SB-564) spans the family from pure nickel through Monel, the Inconels and the Incoloys — one standard, many UNS numbers — and its N08800 chapter covers the forged flanges this page describes, with N08810 and N08811 chapters carrying the H and HT siblings' controlled-carbon requirements. Around it sit the product-form siblings: B408 for bar and rod, B407 for seamless pipe and tube, B409 for plate, sheet and strip, all to the same chemistry. Nothing changes at the flange end: dimensions, drilling and facings follow ASME B16.5, with pressure-temperature ratings from the alloy's tables read at service temperature. The order line reads 'ASTM B564 Incoloy 800 (UNS N08800)' — or the H/HT designation where creep service is named — with the EN designation X10NiCrAlTi32-20 / 1.4876 on the same certificate for European drawings.
What do the SCC immunity and the sulphur advantage mean on this page?
They are the bridge position's two best gifts. The SCC immunity first: at 30-35% nickel, chloride stress corrosion cracking — the mechanism that retires 304 and 316 from hot chloride-bearing water and steam — loses its grip, so feedwater heaters, hot brine exchangers and chloride-touched steam systems specify 800 precisely where stainless has been cracking; this is the massive-nickel route of the site's SCC story, bought at bridge-alloy prices. The sulphur advantage second, and it closes a thread: every high-nickel page on this site has carried the sulphidising-gas warning, and the 601 page conceded that in some sulphur-bearing atmospheres an iron-based rung outlasts the nickel summit — this is that rung. The iron floor dilutes the nickel-sulphur eutectic mechanism, so in reducing sulphidising service the 800 family stands where 600 and 601 corrode — one of metallurgy's tidy reversals, and a named reason reformer and gasification flowsheets keep the bridge alloy on their materials lists.
When does Incoloy 800 hand off — the bridge's four directions?
Down to the stainless ladder where its virtues aren't needed: steady oxidation at moderate stress with no SCC exposure reads 310S or 309 at lower cost — the bridge earns its premium only when the nickel threshold's immunity and stability matter. Up within its own family for rated heat: creep-certified pressure parts read 800H or 800HT by name, as the family FAQ explains — the most common hand-off on this page's enquiries. Across to the Inconel bench when chemistry deepens: 600 where hot halogens, caustic and richer nickel chemistry govern; 601 where cyclic oxidation runs to the summit; 625 where strength and wet severity stack. And across to the wet benches entirely when there is no heat in the duty at all — the stainless wing, duplex and acid ladders serve pure aqueous work at their own economics. The enquiry's temperature, chemistry and code lines place the duty in one pass, and the quotation names the grade honestly.
How is the closing weld on an Incoloy 800 LWN made?
With the bench's great dissimilar filler doing exactly what it was designed for. ERNiCr-3 — the consumable of the 600 page's fame — is the standard wire for the whole 800 family, and here its dissimilar talent is the point rather than a footnote: 800's habitat constantly joins it to stainless piping on one side and nickel-alloy or carbon-steel equipment on the other, and ERNiCr-3 tolerates dilution from every direction while staying stable through service heat. Like-to-like joints follow the family practice: no preheat beyond dryness, no PWHT, nothing to age; scrupulous cleanliness because nickel-bearing alloys punish sulphur, paint and shop grime; a slightly sluggish pool favouring modest heat input and the good access the LWN's straight barrel provides. On H and HT material destined for creep service, procedures also protect the coarse grain and carbon level that the certificate depends on — one more reason the grade line belongs on the enquiry. WPS guidance travels with every supply, filler class stated.
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 sizes and pressure classes do Incoloy 800 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. The order book spans the bridge's two worlds: exchanger and heater nozzles concentrate in Classes 150 and 300, while reformer-adjacent and steam-system duty reaches 600 and above, with ratings read from B16.5's tables at service temperature — where the derating curves govern hard in the hot band, a check our quotation runs as standard. State size, class, barrel length and bore together — the four numbers define the forging — with the grade line (800, 800H, 800HT or dual-certified) and service temperature named, and our quotation returns price, unit weight and delivery per class.
What details are needed to get an accurate Incoloy 800 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, checked against the derating tables at the service temperature; (3) facing — RF (the default), FF or RTJ with ring number; (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 B564 Incoloy 800, UNS N08800 — with the family member named where the duty demands it (800H/800HT for rated creep service, dual-certified where marginal) and the service stated fully: temperature, chemistry, atmosphere; (7) certification — EN 10204 3.1 (our standard) or 3.2 witnessed. Add quantity and destination; quotations normally within 24 hours, with the alloy-market lead time quoted honestly.
Who manufactures Incoloy 800 long weld neck flanges in India?
Tesco Steel & Engineering is an ISO 9001:2015 certified flange manufacturer based in Mumbai, India, producing Incoloy 800 long weld neck flanges to ASTM B564 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 N08800 heats (800H and 800HT to their own specifications, dual-certified where available) kept segregated on the alloy shelf, annealed, machined with the barrel bored to the ordered schedule or drawing, bevelled for the closing weld, PMI-checked on the iron-nickel-chromium signature on every piece, and marked with grade, size, schedule and heat number. Supplied with EN 10204 3.1/3.2 certification and WPS guidance naming the ERNiCr-3 filler — alongside the Incoloy 800 socketweld, weld neck and blind siblings, the 800H/800HT creep grades, the Inconel bench and the complete long weld neck range. Exported to more than 50 countries.
