Inconel 601 Long Weld Neck Flanges — UNS N06601 Nickel-Chromium-Aluminium LWN Manufacturer
Tesco Steel & Engineering manufactures Inconel 601 long weld neck flanges — the oxidation summit of this site's whole bench: ASTM B564, UNS N06601, W.Nr. 2.4851, NiCr23Fe — with ASME B16.5 flange ends in Classes 150–2500 and the barrel made to order. The trades against Alloy 600 read like a design brief: nickel eased to a 58–63% range to afford 21–25% chromium, and 1.0–1.7% aluminium as the signature — the alumina sub-scale that anchors the oxide film through thermal cycling to roughly 1200 °C. The scaling ladder this site has climbed — 304 → 309 → 310S → the nickel bench — ends here: the highest film on any grade page, held on after the thousandth cool-down. The honesty rides along: a soft 205 yield bought deliberately for cycling ductility, no molybdenum and no niobium because this is a hot-gas alloy, not a wet-corrosion one, and the sulphidising-atmosphere warning of every high-nickel page. Hand-offs: 600 where heat meets chemistry, Incoloy 800 for code creep, 625 for strength and acid. One forging, one closing weld with ERNiCrFe-11. Facings: RF / FF / RTJ; small bore on the Inconel 601 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 N06601 · W.Nr. 2.4851NiCr23Fe — The Alumina SignatureOxidation to ~1200 °C — The Site's SummitScale Adherent Through CyclingChloride-SCC Immune · No PWHT550 / 205 MPa AnnealedB16.5 Flange Ends · Class 150–2500EN 10204 3.1 / 3.2 · ISO 9001:2015
Inconel 601 Long Weld Neck Flanges — Specifications at a Glance
What is an Inconel 601 Long Weld Neck Flange?
The oxidation specialist, in the nozzle pattern. An Inconel 601 flange (UNS N06601, ASTM B564) whose neck continues as a long, heavy-walled straight barrel — the nozzle itself — bevelled for one closing butt weld at the furnace or heater shell. Alloy 600's descendant: nickel spent to afford 21–25% chromium, with 1.0–1.7% aluminium building the alumina sub-scale that keeps the film on through cycling to ~1200 °C — the site's highest. Chloride-SCC immune; welds with ERNiCrFe-11, no PWHT. Supplied annealed — 550/205/30, the soft yield bought for cycling ductility. Flange ends per ASME B16.5, Classes 150–2500; barrel length and bore stated by you. EN 10204 3.1 on every lot.
The rule of the ladder, one last time:climb only as high as the thermometer and the cycling demand — every rung is paid in nickel, and descending honestly is engineering too.
What the Alumina Signature Buys
The Scale That Stays On
Beneath the chromia, the aluminium builds an alumina sub-scale that anchors the film — adherent through the thermal cycling that flakes plain nickel-chromium and stainless scales one cool-down at a time.
The Site's Highest Film
~1200 °C continuous — above the stainless top and above the 600 original: where the thermometer genuinely demands the summit, nothing below it serves.
Ductility Where Cycling Lives
The soft 205 yield is a design choice — a nozzle that heats and cools daily lives on its ability to absorb thermal strain, and 601's matrix absorbs it.
The Nickel Family, Kept
Chloride-SCC immunity, stability, weldability with no PWHT — at nearly sixty percent nickel the descendant keeps the family name honestly.
Specification Notes — Getting Inconel 601 Long Weld Necks Right
Three honest notes.A hot-gas alloy, not a wet-corrosion one: no molybdenum, no niobium — reducing acids and hot wet chlorides belong to 625 and the Hastelloy bench; buying the oxidation summit for a wet job pays for the wrong property. Climb only as high as needed: steady oxidation at 1100 °C and below reads 310S at a fraction of the price, and code-creep duty reads Incoloy 800H — 601's premium buys the summit and the cycling anchor, nothing else. And sulphidising gas remains the nickel family's enemy: in some reducing sulphur-bearing atmospheres an iron-based rung outlasts the nickel summit — name the atmosphere on every enquiry.
How Our Inconel 601 LWN Flanges Are Manufactured
1
Forging — each piece individually forged from certified N06601 heats kept segregated on the nickel shelf, with the barrel integral — no welded build-ups.
2
Annealing — softened and homogenised, the ductile cycling matrix set for service; records retained against the heat number.
3
Verification — chemistry per heat with the chromium window and the 1.0–1.7% aluminium signature certified; mechanicals per heat at the 550/205 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 aluminium line alongside the nickel-chromium signature — the line that separates 601 from 600 on the shelf; 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 ERNiCrFe-11 filler; faces and bevels protected, packed sea-worthy.
Where Inconel 601 LWN Flanges Are Used
Where the thermometer and the cycling meet: heat-treatment furnaces — muffles, retorts, radiant tubes and baskets, with the sight ports, burner mounts, thermocouple standpipes and access nozzles this page forges — incineration and waste-treatment plants, calciners and combustion hardware beyond the stainless ladder's reach, petrochemical furnace connections at the hot end, ammonia and nitriding plant hardware where 601's standing in nitrogen-bearing atmospheres is a named credential, and power-generation hot-gas paths. The barrel does the thermal-gradient work: hot at the shell, cool enough to bolt at the face. 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
Inconel 601 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 — temperature, cycling and atmosphere place the duty on the ladder:
1
Size & standard — e.g. 4″ 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 Inconel 601 (UNS N06601) — with the duty named fully: maximum temperature, cycling pattern (continuous / daily / batch), atmosphere — placing it against 310S below and 600 / 800H across.
6
Certification — EN 10204 3.1 (our standard) / 3.2 witnessed.
Example: “LWN Flange RF, 3″ NB, ASME B16.5 Class 150, barrel 300 mm, Sch 40 bore, standard pattern, ASTM B564 Inconel 601 UNS N06601, heat-treatment furnace access nozzles — 1150 °C daily cycling, air atmosphere, EN 10204 3.1 — 4 pcs.” Quotations normally within 24 hours with price, unit weight and delivery.
An Inconel 601 long weld neck flange is a forged nickel-chromium-aluminium alloy flange — UNS N06601, W.Nr. 2.4851, NiCr23Fe, 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 furnace, heater or vessel shell. Inconel 601 is the oxidation specialist of the Inconel bench: Alloy 600's descendant with nickel eased to afford more chromium, and 1.0-1.7% aluminium building an alumina sub-scale that keeps the oxide film adherent through thermal cycling to roughly 1200°C — the highest service film on this site's whole bench. Chloride-SCC immunity rides along on the nickel base. Flange ends follow ASME B16.5 in Classes 150 to 2500; the barrel is machined to the ordered length and bore. Supplied annealed at 550/205 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.
How do the trades read against Alloy 600 — chemistry as design?
Line by line, like a design brief for more heat. Nickel becomes a range rather than a floor — 58.0-63.0% against 600's ≥72% — because 601 spends some nickel to afford what oxidation actually wants: chromium jumps from 14-17% to 21-25%, deepening the scale-forming reserve, and iron widens to the working balance that carries the economy. The aluminium is the signature — 1.0-1.7%, dosed not for hardening (this is no K-500 or superalloy trick) but for the alumina sub-scale of the next FAQ. What is deliberately absent tells the other half: no molybdenum and no niobium, because 601 is a hot-oxidation alloy, not a wet-corrosion one — the acid capabilities live with 625 and the Hastelloy bench. And what survives the trades matters too: at nearly sixty percent nickel the chloride-SCC immunity, the structural stability and the nickel family's fabrication character all remain — the descendant keeps the family name honestly.
What does the aluminium do — why the scale stays on through cycling?
It solves the failure mode that actually kills furnace hardware. A chromia film protects beautifully at steady temperature — but real heat-treatment equipment cycles, and every cool-down puts thermal-expansion mismatch stress between scale and metal until the scale spalls off, taking its protection with it and forcing the metal to rebuild the film from fresh chromium each cycle: the alloy literally oxidises away one flake at a time. 601's aluminium changes the mechanism. Beneath the chromia, the aluminium oxidises into a thin alumina sub-scale that anchors the film to the metal, and the composite scale stays adherent through cycling that strips plain nickel-chromium and stainless grades. That is the working meaning of 601's ~1200°C rating: not merely that the film forms at extreme temperature, but that it is still there after the thousandth cool-down. Cyclic-oxidation resistance is the franchise — the daily-cycling furnace, not just the hot one, is where 601 earns its premium.
Where does 601 sit on the site's scaling ladder — the summit?
At the top of the thread this site has climbed across two benches. The stainless scaling ladder runs 304 at roughly 870°C, 309 near 1000°C, 310S near 1100°C — each rung buying oxidation ceiling with chromium and nickel on an iron base, each honest about its strength going nominal as the thermometer rises. The nickel bench then re-enters the climb: Alloy 600 matches the stainless top's ceiling while adding nickel-family chemistry and stability, and 601 finishes the ascent — roughly 1200°C, the highest continuous-service film on any grade page here, held on through cycling by the alumina anchor. The ladder's economics stay honest at every rung: steady, moderate-stress oxidation duty belongs as low on the ladder as the temperature allows, because each step up is paid in nickel; 601 is specified where the thermometer, the cycling, or both, genuinely demand the summit — and where they do, nothing below it serves.
What is the chemical composition of Inconel 601 (UNS N06601)?
Nickel 58.0-63.0%, chromium 21.0-25.0%, aluminium 1.0-1.7%, iron the balance (roughly 14%), manganese ≤1.0%, carbon ≤0.10%, silicon ≤0.5%, sulphur ≤0.015%, copper ≤1.0%. Read the trades against Alloy 600: nickel becomes a range rather than a ≥72% floor — 601 spends some nickel to afford more chromium and iron; chromium jumps from 14-17 to 21-25%, deepening the scale-forming reserve; and the aluminium is the grade's signature, dosed for the alumina sub-scale rather than for hardening. No molybdenum, no niobium — this remains a hot-oxidation alloy, not a wet-corrosion one. Chemistry is verified per heat, PMI-confirmed with the aluminium line read alongside the nickel-chromium signature — the line that separates 601 from 600 on the shelf — and travels on the EN 10204 3.1 MTC.
What are the mechanical properties of Inconel 601 long weld neck flanges?
Annealed to ASTM B564: tensile strength 550 MPa (80 ksi) minimum, yield strength 205 MPa (30 ksi) minimum, elongation 30% minimum — note the yield sits slightly below Alloy 600's 240, the small price of the leaner nickel and the ductility the cycling duty wants: a furnace nozzle that heats and cools daily lives on its ability to absorb thermal strain, and 601's soft, ductile matrix absorbs it. As across the hot-service family, the room-temperature certificate is not the number that sells the alloy — what matters is the structure's stability and the film's adherence deep into red heat, where 601 keeps working order long after lower rungs have scaled away. For nozzle duty the frame is the bench's: class-governed geometry, B16.5 ratings read at service temperature where the derating curves govern hard, and the heavy LWN barrel adding stiffness where nozzle loads bear. Code-rated creep duty remains Incoloy 800H's franchise, as the hand-off FAQ keeps honest.
What is the ASTM B564 specification for Inconel 601 flanges?
The nickel bench's shared forging standard, one chapter along from the 600's. 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 N06601 chapter covers the forged flanges this page describes. Around it sit the product-form siblings: B166 for bar and rod, B167 for seamless pipe and tube, B168 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 its tables for the alloy — read at the service temperature, which in 601's habitat is the number that actually governs. The order line reads 'ASTM B564 Inconel 601 (UNS N06601)', with the EN designation NiCr23Fe / 2.4851 on the same certificate for European drawings.
What is Inconel 601 NOT for — the wet-corrosion honesty?
Wet chemistry, stated plainly. The molybdenum and niobium that buy acid capability are exactly the elements 601's design left out: reducing acids, hot wet chlorides and severe aqueous duty belong to 625, to the Hastelloy bench and to the acid ladder — buying the oxidation summit for a wet-corrosion job pays a premium for the wrong property. The distinctions worth keeping: chloride stress corrosion cracking immunity survives — the nickel base sees to that, so incidental chloride exposure is no alarm — and the dry-halogen credentials of the family carry over at moderate temperatures; but the franchise is hot gas and flame, not process liquor. The atmosphere honesty carries over from every high-nickel page too: reducing sulphidising gas attacks nickel alloys through the nickel-sulphur eutectic, so sulphur-bearing furnace atmospheres must be named on the enquiry — in some of them, an iron-based rung of the ladder actually outlasts the nickel summit, and we will say so when the enquiry shows it.
When does 601 hand off — down the ladder, across the bench?
Down by thermometer and economics: steady oxidation at 1100°C and below reads 310S; near 1000°C, 309; and where cycling is mild and stress modest, the stainless ladder's economics win every time — 601's premium buys the summit and the spallation resistance, and a duty that needs neither should not pay for them. Across by mission: Alloy 600 remains the default where heat meets chemistry — chlorination, caustic, mixed duties at furnace-adjacent temperatures — trading 601's last 100 degrees and alumina anchor for a rounder franchise; Incoloy 800H holds the code-creep certificates for rated hot pressure parts, a mission 601 does not claim; and 625 takes strength and wet severity. The practical enquiry line: state the maximum temperature, the cycling pattern (continuous, daily, batch) and the atmosphere — those three answers place the duty on the ladder in one pass, and the quotation names the rung honestly.
How is the closing weld on an Inconel 601 LWN made?
With the nickel family's habits and the grade's own consumable. The filler of record is ERNiCrFe-11, matching 601's aluminium-bearing chemistry so the weld metal builds the same adherent scale as the parent — the point of the alloy, preserved through the joint; where a procedure standardises on the bench's universal ERNiCr-3, the joint serves but its scale behaviour reads closer to 600's, a distinction worth making on cycling duty. Otherwise the practice is the family's: no preheat beyond dryness, no PWHT, nothing to age; scrupulous cleanliness because nickel punishes sulphur, paint and shop grime with cracking; a sluggish pool favouring modest heat input and the good access the LWN's straight barrel provides. The closing weld at the furnace or heater shell inherits the plant's qualified procedure, and 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 Inconel 601 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 is the furnace bench's: Classes 150 and 300 dominate almost completely — in 601's habitat the temperature, the cycling and the atmosphere are the load, and pressure is usually modest — with the occasional higher class where a pressurised hot-gas system specifies it. At these temperatures the B16.5 derating curves govern absolutely, so the class for a hot nozzle is chosen from the tables at temperature, not at ambient — a check our quotation runs as standard. State size, class, barrel length and bore together — the four numbers define the forging — with the service temperature and cycling pattern named, and our quotation returns price, unit weight and delivery per class.
What details are needed to get an accurate Inconel 601 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, 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 Inconel 601, UNS N06601 — with the duty named fully: maximum temperature, cycling pattern and atmosphere (sulphur-bearing gas especially), so the scaling-ladder economics below and the 600, 800H and 625 questions across are checked honestly; (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 Inconel 601 long weld neck flanges in India?
Tesco Steel & Engineering is an ISO 9001:2015 certified flange manufacturer based in Mumbai, India, producing Inconel 601 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 N06601 heats kept segregated on the nickel shelf, annealed, machined with the barrel bored to the ordered schedule or drawing, bevelled for the closing weld, PMI-checked with the aluminium line read alongside the 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 ERNiCrFe-11 filler — alongside the Inconel 601 socketweld, weld neck and blind siblings, the 600 original, the Incoloy and 625 neighbours, and the complete long weld neck range. Exported to more than 50 countries.
