NiCr26MoW Forgings | Alloy 333 / UNS N06333 / 2.4608 Factory

1. What NiCr26MoW is

NiCr26MoW is a solid-solution strengthened nickel-chromium-iron alloy of roughly 45 % Ni, 25 % Cr and 3 % each of molybdenum, cobalt and tungsten. It works from aqueous corrosion right up to white heat, which few materials manage.

The alloy was developed for furnace and process equipment that meets more than one form of attack in the same cycle. Oxidising flue gas in one part of the run, a carburising or sulfidising atmosphere in the next, then a quench. Four additions do that work.

Why each element is there

Chromium, 24 to 27 %. Forms the Cr₂O₃ film that carries oxidation and sulfidation resistance. The high nickel base keeps that film adherent through thermal cycling instead of letting it spall off.
Silicon, 0.75 to 1.50 %. High for a nickel alloy, and deliberately so. Silicon stabilises the protective scale in low-oxygen, carbon-rich gas. It is the reason NiCr26MoW handles carburisation and metal dusting better than Incoloy 800H or RA330.
Molybdenum and tungsten, about 3 % each. Heavy atoms sitting in the austenitic matrix. They give creep strength above 1000 °C with no precipitation hardening involved.
Cobalt, about 3 %. Adds further solid-solution strength and keeps the structure stable through long exposure.

Strength comes from solid solution, not from gamma-prime precipitates. NiCr26MoW is therefore not age hardened. It ships solution annealed, and it stays tough and weldable after thousands of hours at temperature.

Name origin. The 333 in Alloy 333 refers to the nominal 3 % Co / 3 % Mo / 3 % W. The EN name NiCr26MoW states the same chemistry from the nickel base upward.

2. Designations and equivalents

NiCr26MoW, 2.4608, UNS N06333, Alloy 333 and RA 333 are five names for one material. A drawing calling out any of them can be quoted from the same forging stock.

Cross-reference of NiCr26MoW designations
System	Designation	Notes
EN chemical name	NiCr26MoW	European chemical designation
EN / DIN material no.	2.4608	Werkstoffnummer
UNS	N06333	North American unified number
Common trade name	Alloy 333	Generic industry name
Registered brand	RA 333^®	Trademark of Rolled Alloys, Inc., shown here for identification
ASTM, plate/sheet/strip	ASTM B718	Chemistry basis usually cited for forgings
ASTM, bar	ASTM B719	Bar and billet
ASTM, seamless pipe/tube	ASTM B722	Seamless
ASTM, welded pipe	ASTM B723	Welded
Welding consumable	N06333 bare wire, matching electrode	Matching composition, no preheat

There is no dedicated ASTM product specification for N06333 forgings. Forgings are normally ordered to the ASTM B718 or B719 chemistry limits, with mechanical properties, heat-treatment condition and NDT acceptance agreed on the purchase order. We write our NiCr26MoW order confirmations on that basis.

3. Chemical composition of NiCr26MoW

NiCr26MoW contains 44.0 to 47.0 % Ni, 24.0 to 27.0 % Cr, 2.50 to 4.00 % each of Mo, Co and W, 0.75 to 1.50 % Si, max 0.08 % C, max 2.00 % Mn, balance iron.

NiCr26MoW / UNS N06333 chemical composition, weight %
Limit	Ni	Cr	Mo	Co	W	Si	Mn	C	Fe
Min	44.00	24.00	2.50	2.50	2.50	0.75	–	–	–
Max	47.00	27.00	4.00	4.00	4.00	1.50	2.00	0.08	Balance

EN 2.4608 limits, where they differ

Drawings written to the European material number instead of UNS N06333 use slightly tighter ranges and add tramp-element limits. We melt to whichever set the order specifies.

Additional and differing limits under EN 2.4608, weight %
Element	EN 2.4608	UNS N06333	Comment
C	0.03 to 0.08	0.08 max	EN sets a carbon minimum for creep strength
Cr	24.0 to 26.0	24.0 to 27.0	EN range is narrower at the top
Si	0.70 to 1.50	0.75 to 1.50	Effectively the same
P	0.030 max	not specified	Tramp limit
S	0.015 max	not specified	Tramp limit
Cu	0.50 max	not specified	Tramp limit

Every heat is checked twice. A ladle analysis goes on the certificate, and a PMI check is run on the finished forging before packing.

4. Mechanical properties of NiCr26MoW

Solution annealed at 20 °C, NiCr26MoW gives a minimum tensile strength of 550 MPa, minimum 0.2 % proof strength of 240 MPa and minimum elongation of 30 %. Typical forged and annealed values run higher: about 738 MPa tensile, 324 MPa proof, 48 % elongation.

Tensile Rm, min: 550 N/mm²
Proof Rp0.2, min: 240 N/mm²
Elongation A5, min: 30 %
Modulus of elasticity: 201 kN/mm²
Typical Rm, forged: 738 N/mm²
Typical elongation: 48 %

Typical properties from room temperature to 1204 °C

What puts this alloy into hot service is the load it still carries at 871 °C and above. Ductility stays high across the whole range, and that is what keeps quench fixtures from cracking after repeated cycles.

Typical elevated-temperature tensile properties, solution annealed
Temperature	Tensile strength	0.2 % yield strength	Elongation
21 °C / 70 °F	738 MPa (107,000 psi)	324 MPa (47,000 psi)	48 %
871 °C / 1600 °F	190 MPa (27,500 psi)	165 MPa (23,900 psi)	75 %
982 °C / 1800 °F	108 MPa (15,700 psi)	83 MPa (12,100 psi)	64 %
1093 °C / 2000 °F	51 MPa (7,400 psi)	45 MPa (6,500 psi)	25 %
1204 °C / 2200 °F	28 MPa (4,000 psi)	24 MPa (3,500 psi)	106 %

Typical values for solution-annealed material, converted at 1 psi = 0.00689 MPa. These are not guaranteed minima. Guaranteed properties for a given forging are agreed on the order and reported on the EN 10204 certificate for the actual heat and test location.

5. Physical properties

At 20 °C NiCr26MoW has a density of 8.2 g/cm³, thermal conductivity of 11.1 W/m·K, specific heat of 441 J/kg·K and electrical resistivity of 1.14 Ω·mm²/m.

Density: 8.2 g/cm³
Thermal conductivity: 11.1 W/m·K
Specific heat: 441 J/kg·K
Electrical resistivity: 1.14 Ω·mm²/m
Modulus of elasticity: 201 kN/mm²
Max. service temp.: 1204 °C

Weight estimate for quotation. At 8.2 g/cm³ a NiCr26MoW forging weighs about 4.5 % more than the same part in carbon steel. For a rough forged ring, weight in kg is roughly π × (OD − thickness) × thickness × height × 8.2 divided by 1,000,000, with dimensions in millimetres. Send the drawing and we return the exact forged weight with the price.

Machining and welding data

Machinability. Around 12 to 15 % of B1112 free-cutting steel. Turn at 6 to 8 m/min (20 to 25 sfm) with high-speed-steel tooling, faster with carbide. Rigid set-ups, positive rake and a heavy positive feed to cut under the work-hardened layer.
Welding. Use matching N06333 bare wire or matching coated electrodes. No preheat. Keep interpass temperature below 100 °C (212 °F) and run stringer beads instead of a wide weave.
Forming. Work hardens fast, so plan intermediate anneals for heavy cold work. Ground or deburred edges before any tight bend.

6. Corrosion and high-temperature resistance

NiCr26MoW resists oxidation, carburisation, sulfidation, metal dusting and thermal shock. On shutdown it also resists sulfuric-acid dew-point corrosion and polythionic acid stress-corrosion cracking, which is what makes it a shutdown-tolerant furnace alloy.

Oxidation

The 24 to 27 % chromium forms a stable Cr₂O₃ scale that stays protective in continuous service to about 1204 °C. Because the base is nickel rich, that scale holds through thermal cycling rather than spalling and re-forming, and it is the repeated re-forming that consumes chromium in leaner heat-resistant grades.

Carburisation and metal dusting

High nickel plus 0.75 to 1.50 % silicon gives much better carburisation resistance than Incoloy 800H, RA330 or cast HK and HP grades. That matters most in ethylene furnace hardware, heat-treatment fixtures running endothermic atmospheres, and syngas or direct-reduction plant where metal dusting eats conventional alloys.

Thermal shock

NiCr26MoW takes repeated oil or water quenching from red heat unusually well. Quench fixtures, baskets, trays and rotating retort parts forged in this alloy normally outlast 330-type equivalents by a wide margin on the same cycle.

Shutdown corrosion

When a sulfur-bearing furnace cools below the acid dew point, condensed sulfuric acid attacks most heat-resistant alloys, and sensitised austenitic materials crack by polythionic acid stress-corrosion cracking. NiCr26MoW resists both, so the equipment survives the shutdown as well as the campaign.

Where this alloy is the wrong answer. NiCr26MoW is a heat-resisting alloy, not a wet-corrosion alloy. For strong reducing acids, seawater or sour-service wellhead duty, specify Hastelloy C-276, Incoloy 825 or Inconel 625 instead. We forge all of them. If your service condition suits a cheaper grade, we will say so.

7. How we forge and heat treat NiCr26MoW

We melt NiCr26MoW by EAF plus VOD, with ESR refining on request, forge it between 1180 °C and 950 °C at a minimum 4:1 ratio, then solution anneal at 1120 to 1150 °C with rapid cooling. The alloy is never age hardened.

Melting route

Electric arc furnace melting followed by vacuum oxygen decarburisation gives the low carbon, sulfur and gas content this alloy needs. For pressure-retaining parts, rotating components and any order with a tight ultrasonic acceptance class, we add electroslag remelting to refine the solidification structure and cut segregation and inclusion content.

Open-die forging window

Typical NiCr26MoW hot-working and heat-treatment practice
Operation	Parameter	Purpose
Soak and start forging	1160 to 1180 °C	Full solution of carbides before deformation
Finish forging	not below 950 °C	Below this the alloy cracks instead of flowing
Reheats	As required	The working window is narrow, so reheating beats forcing
Forging ratio	4:1 minimum	Breaks up cast structure and closes porosity
Solution anneal	1120 to 1150 °C	Dissolves carbides, restores ductility and corrosion resistance
Cooling from anneal	Rapid air cool or water quench	Prevents carbide re-precipitation and sensitisation
Ageing	Not applied	Solid-solution alloy. Ageing would embrittle it, not strengthen it

Typical shop practice. Final parameters are fixed per part on the manufacturing plan and recorded with furnace charts on the EN 10204 3.1 or 3.2 certificate.

On grain size. The hot-working range for NiCr26MoW is narrow, and light finishing blows delivered in the 950 to 1000 °C band are the usual cause of duplex grain structure and of ultrasonic noise that later fails an EN 10228-3 class 3 inspection. We plan reheats around this, which is why we ask for the ultrasonic acceptance class before quoting rather than after.

8. NiCr26MoW forging forms and size range

We supply NiCr26MoW as forged rings, seamless rolled rings, flanges, shafts, discs, sleeves, bushings, tube sheets, valve bodies, nozzles, blocks and round bars, from a few kilograms up to about 20 tonnes per piece, with ring outside diameters to roughly 4000 mm.

NiCr26MoW open-die forging capability
Product form	Size range	Typical use
Seamless rolled rings	OD 200 to 4000 mm, height to 1000 mm	Casings, retort flanges, burner rings
Forged rings and sleeves	OD 150 to 2500 mm, wall from 30 mm	Bushings, liners, muffle sections
Forged flanges	DN 15 to DN 2000, ASME B16.5 / B16.47 / EN 1092-1	Piping, vessels, headers
Shafts, spindles, eccentric shafts	Dia. 80 to 1200 mm, length to 12,000 mm	Fans, rotating retorts, drives
Discs, blanks, tube sheets	Dia. to 3000 mm, thickness to 600 mm	Tube sheets, covers, turbine blanks
Blocks, bodies, valve parts	To 20,000 kg per piece	Valve bodies, seats, stems, nozzles
Round bar and billet	Dia. 20 to 600 mm	Machined parts, weld prep, fasteners

Supplied condition: solution annealed, rough machined or as forged with machining allowance, sand blasted or pickled, marked with heat number, grade and our order number. Minimum order is one piece. Every part is open-die forged to your drawing, so there is no tooling charge and no volume threshold.

9. Where NiCr26MoW forgings are used

NiCr26MoW forgings go into industrial furnace hardware, petrochemical and refinery internals, gas turbine casings and combustor parts, power plant high-temperature piping components, and chemical process equipment exposed to carburising or sulfidising gas.

Heat treatment plant

Quench fixtures, baskets, trays, grids, radiant tube components, rotating retorts, muffle sections and fan shafts. Anywhere parts are cycled from red heat into oil or water.

Petrochemical and refining

Ethylene furnace hardware, reformer and cracker internals, transfer-line components, tube sheets and nozzles in carburising service, plus columns, towers, preheaters and process modules.

Gas turbines

Combustion chamber components, casing rings, transition hardware and mounting rings, where oxidation resistance and thermal-shock tolerance decide component life.

Power generation

High-temperature header and piping components, superheater and reheater hardware, burner rings and support forgings in advanced coal-fired and waste-to-energy plant.

Valves and flow control

Forged valve bodies, seat rings, stems, discs and blocks for ball, gate, globe, check and plug valves running hot, sulfur-bearing or carburising media.

Chemical process

Calciner and kiln components, sulfur recovery hardware, incinerator internals, crystalliser parts and processing-unit forgings that see acid dew point on shutdown.

10. Inspection, testing and certificates

Every NiCr26MoW forging ships with an EN 10204 3.1 certificate as standard. EN 10204 3.2 with third-party witness by TUV, SGS, BV, DNV or Lloyd's Register is available on request. Ultrasonic testing follows EN 10228-3, SEP 1921 or ASTM A388 to the class stated on the order.

Standard inspection scope for NiCr26MoW forgings
Check	Standard or method	Status
Chemical analysis	Ladle analysis plus product check, spectrometer	Standard
PMI	Portable XRF on the finished part	Standard
Tensile test	ASTM E8 or ISO 6892-1, room temperature	Standard
Hardness	Brinell, ASTM E10	Standard
Ultrasonic testing	EN 10228-3, SEP 1921, ASTM A388	Standard, class per order
Dimensional report	Against customer drawing	Standard
Grain size	ASTM E112	On request
Elevated-temperature tensile	ASTM E21	On request
Intergranular corrosion	ASTM G28 method A	On request
Liquid penetrant	ASTM E165 or EN ISO 3452	On request
Certificate	EN 10204 3.1 standard, 3.2 on request	With every shipment

Tell us the ultrasonic acceptance class, the certificate type and any customer or notified-body witness points before quotation. Those decide the melting route and the forging plan, and they cannot be added afterwards once a part has been forged.

11. NiCr26MoW compared with alternative alloys

Choose NiCr26MoW when carburisation and thermal shock dominate. Choose Inconel 625 for wet corrosion and strength below 800 °C, Incoloy 800H for cheaper mild oxidising service, and Haynes 230 or Inconel 617 when creep strength above 1000 °C governs.

Selection comparison, heat-resistant forging grades
Alloy	Ni / Cr, %	Max. service	Strongest at	Choose it when
NiCr26MoW 2.4608 / N06333	45 / 25	1204 °C	Carburisation, thermal shock, dew-point corrosion	Furnace fixtures and petrochemical internals that are quenched, carburised and shut down repeatedly
Inconel 625 2.4856 / N06625	58 / 21	about 980 °C	Aqueous corrosion, strength to 800 °C	Seawater, sour service, high strength at moderate temperature
Inconel 617 2.4663 / N06617	52 / 22	about 1100 °C	Creep strength above 1000 °C	Gas turbine and USC power components governed by creep rupture
Incoloy 800H / 800HT 1.4958 / N08810	32 / 21	about 1100 °C	Cost per kilogram	Mild oxidising service where budget outweighs carburisation risk
Hastelloy X 2.4665 / N06002	47 / 22	about 1150 °C	Oxidation with good fabricability	Gas turbine combustor sheet and ducting hardware
Haynes 230 2.4733 / N06230	57 / 22	about 1150 °C	Long-term creep and thermal stability	Sustained load at very high temperature over long campaigns
AISI 330 / RA330 1.4864 / N08330	35 / 19	about 1150 °C	Economy in heat-treat fixtures	Lighter-duty furnace fixtures where creep strength is not critical

Maximum service temperatures are practical continuous-service guidance for oxidising atmospheres, not code-allowable design temperatures. Design stresses must come from the applicable design code and from the real atmosphere, stress and cycle of your equipment.

12. How to order NiCr26MoW forgings

Send a drawing or dimensioned sketch to sales@steelforgepieces.com. A quotation with forged weight, price, lead time and inspection plan comes back within 12 working hours. Minimum order is one piece and typical lead time is 25 to 45 days from drawing approval.

Send the drawing

Email a drawing, sketch or rough-machined dimensions, stating NiCr26MoW / Alloy 333 / UNS N06333, quantity, required condition and any NDT or certificate requirement. PDF, STEP and DWG are all fine.
Receive the quotation

Within 12 working hours you get forged weight, unit price, lead time, the proposed melting route and the inspection plan we intend to run.
Approve the manufacturing plan

We confirm forging allowance, heat-treatment condition, ultrasonic acceptance class and certificate type, EN 10204 3.1 or 3.2, before any metal is melted.
Production, inspection, shipment

Melting, forging, solution annealing, machining, testing and packing, then shipment from Shanghai or Ningbo with full documentation. Normally 25 to 45 days after drawing approval.

Fastest route to a price. Open a pre-filled RFQ email, or call +86-189-2135-9659. English and Chinese are both spoken. WhatsApp and WeChat use the same number.

13. Frequently asked questions about NiCr26MoW

What is NiCr26MoW?

NiCr26MoW is the EN chemical designation for a nickel-chromium-iron alloy with molybdenum, cobalt, tungsten and silicon additions. It carries material number 2.4608 and UNS N06333, and is sold commercially as Alloy 333 or RA 333. Nominal content is 45 % nickel, 25 % chromium and about 3 % each of molybdenum, cobalt and tungsten, balance iron. It is used where oxidation, carburisation and thermal-shock resistance are needed to about 1204 °C. Jiangyin Jiangnan Metal Co., Ltd. supplies it as open-die forgings.

Is NiCr26MoW the same as Alloy 333, UNS N06333 and RA 333?

Yes. NiCr26MoW (EN chemical designation), 2.4608 (Werkstoff number), UNS N06333 (American designation), Alloy 333 (trade name) and RA 333 (a registered brand of Rolled Alloys) all describe the same alloy. The 333 refers to the nominal 3 % each of cobalt, molybdenum and tungsten.

What is the chemical composition of NiCr26MoW?

44.0 to 47.0 % Ni, 24.0 to 27.0 % Cr, 2.50 to 4.00 % Mo, 2.50 to 4.00 % Co, 2.50 to 4.00 % W, 0.75 to 1.50 % Si, max 2.00 % Mn, max 0.08 % C, balance iron. EN 2.4608 narrows chromium to 24.0 to 26.0 % and silicon to 0.70 to 1.50 %, and adds limits of max 0.030 % P, max 0.015 % S and max 0.50 % Cu.

What is the maximum service temperature of NiCr26MoW?

About 1204 °C (2200 °F) in continuous service. High-temperature strength stays good above 1000 °C, which is the main reason the alloy is chosen over Incoloy 800H or RA330 for furnace and petrochemical hardware. The practical limit for a given part depends on stress, atmosphere and cycle.

How is NiCr26MoW heat treated after forging?

It is solution annealed, never age hardened. We anneal NiCr26MoW forgings at 1120 to 1150 °C followed by rapid air cooling or water quenching to dissolve carbides and restore ductility and corrosion resistance. Strength comes from solid solution rather than precipitates, so an ageing cycle would embrittle the alloy instead of strengthening it.

Can NiCr26MoW be welded?

Yes. Weld with matching N06333 bare wire or matching coated electrodes. Do not preheat, hold interpass temperature below 100 °C (212 °F) and use reinforced stringer beads rather than a wide weave. A post-weld solution anneal is recommended where the part will see carburising service or where full corrosion resistance is required at the weld.

What forging shapes can be produced in NiCr26MoW?

Forged rings and seamless rolled rings, flanges, shafts, discs, blanks, sleeves, bushings, tube sheets, valve bodies, nozzles, blocks and round bars, all made to customer drawing. Single-piece weights run from a few kilograms to roughly 20 tonnes, with ring outside diameters to about 4000 mm.

What certificates are supplied with NiCr26MoW forgings?

An EN 10204 3.1 mill certificate as standard, with EN 10204 3.2 witnessed by TUV, SGS, BV, DNV or Lloyd's Register available on request. Ultrasonic testing is carried out to EN 10228-3, SEP 1921 or ASTM A388 at the acceptance class stated on the order, and PMI is performed on the finished part before packing.

How does NiCr26MoW compare with Inconel 625 and Incoloy 800H?

Inconel 625 is stronger below about 800 °C and far better in wet corrosion, but it loses strength faster above that and is less carburisation resistant. Incoloy 800H is cheaper but has much lower creep strength and a lower practical ceiling. NiCr26MoW sits between them. It holds strength to 1204 °C, handles carburisation and metal dusting far better than 800H because of its 0.75 to 1.50 % silicon, and tolerates repeated water or oil quench thermal shock.

What is the minimum order quantity and lead time for NiCr26MoW forgings?

One piece. Every part is open-die forged to drawing, so there is no tooling cost and no volume threshold. Typical lead time is 25 to 45 days from drawing approval, depending on weight, heat-treatment cycle and inspection scope. Quotations are returned within 12 working hours.

Who supplies NiCr26MoW forgings?

Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, manufactures and exports NiCr26MoW (Alloy 333 / UNS N06333 / 2.4608) forgings worldwide. Enquiries to sales@steelforgepieces.com or +86-189-2135-9659.

14. About the manufacturer

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu Province, China, producing forged rings, flanges, shafts, discs, sleeves, tube sheets and bars in carbon steel, alloy steel, tool steel, stainless steel and nickel-based alloys including NiCr26MoW.

Jiangyin sits in the Yangtze River delta special-steel cluster, two hours from Shanghai port. Working to drawing rather than to a catalogue means we quote single pieces and prototype forgings as readily as repeat production, and the inspection plan is written around your requirement instead of around a stock specification.

Company: Jiangyin Jiangnan Metal Co., Ltd.
Open-die forging factory
Address: No.1 Chengxiqiao Road, Zhouzhuang Town,
Jiangyin City, Jiangsu Province, China
Telephone, WhatsApp, WeChat: +86-189-2135-9659
Email: sales@steelforgepieces.com
Website: www.steelforgepieces.com
Export markets: Europe, North America, Middle East, South-East Asia, Japan, Korea, Australia

15. Related nickel alloy forging grades

We forge the full nickel-alloy range to drawing. If NiCr26MoW is not right for your service condition, these are the grades most often specified instead.

NiCr26MoW Forgings Alloy 333, UNS N06333, W.Nr. 2.4608. Forged rings, seamless rolled rings, flanges, shafts, discs, sleeves, tube sheets and bars, made to drawing.

Summary