2.4819 Forgings: UNS N10276 / NiMo16Cr15W / Alloy C-276 Forged Rings, Flanges, Shafts and Tube Sheets

• W.Nr. 2.4819
• UNS N10276
• NiMo16Cr15W
• DIN 17744
• ASTM B564 / B574
• ASME SB-564
• AMS 5750
• VdTÜV 400
• JIS NW0276
• GB NS3306
• Hastelloy® C-276 (Haynes International trademark)

Published: 18 June 2022 Last updated: 10 August 2026 Technically reviewed by: Jiangyin Jiangnan Metal Co., Ltd. Metallurgical Engineering Team

This datasheet is written for buyers, specifiers and inspectors of 2.4819 forgings. It covers the chemistry limits under each standard, the mechanical and physical properties reported on a certificate, the corrosion envelope and its boundaries, heat treatment and fabrication practice, and the ordering decisions that account for most rejected material. Calculators for weight, media selection, alloy substitution, sour-service screening and RFQ drafting are placed in the relevant sections.

01 / IdentificationWhat is 2.4819 (UNS N10276 / Alloy C-276)?

2.4819 is a wrought, solid-solution-strengthened nickel-molybdenum-chromium alloy with a tungsten addition, developed to resist both reducing and oxidising corrosive media in the same component. The Werkstoff number 2.4819 is assigned in the German material numbering system; the same alloy carries the DIN name NiMo16Cr15W, the American designation UNS N10276, the Japanese designation NW0276 and the Chinese designation NS3306 (formerly NS334).

Three features of the chemistry account for most of the service behaviour:

• Molybdenum at 15–17 % gives resistance to reducing acids (hydrochloric, dilute sulphuric, phosphoric) and provides the pitting and crevice-corrosion resistance that makes the alloy viable in hot chloride solutions where austenitic and duplex stainless steels fail.
• Chromium at 14.5–16.5 % supplies resistance to oxidising media such as nitric acid and ferric chloride. The combination of high molybdenum with substantial chromium allows 2.4819 to handle process streams that alternate between reducing and oxidising conditions, which single-purpose alloys generally cannot.
• Carbon capped at 0.010 % and silicon at 0.08 %, both very low by general standards, suppress the grain-boundary carbide and intermetallic precipitation that would otherwise sensitise the heat-affected zone. These limits are the reason most 2.4819 fabrications enter service as-welded, without post-weld solution annealing.

2.4819 is not age-hardenable. It gains its strength from solid-solution strengthening only, so there is a single delivery condition, solution annealed, with no H-condition, aging cycle or temper to specify. A certificate for 2.4819 that names an aging treatment should be queried. Cold work raises strength, but at the cost of the sour-service hardness limit and of corrosion performance, so forgings are supplied fully annealed.

The alloy is austenitic and essentially non-magnetic (relative permeability ≈ 1.0002). For inspection this means that magnetic particle examination cannot be used on 2.4819. Specify liquid penetrant instead. An MT clause carried over from a carbon-steel drawing is a frequent cause of dispute at the pre-inspection meeting.

For context on where 2.4819 sits among corrosion-resistant alloys: it is roughly two and a half times the raw-material cost of Alloy 825, meaningfully more expensive than Alloy 625, and comparable to Alloy C-22. It is specified where the process stream combines chlorides, acid and temperature, and where the cost of unplanned downtime outweighs the material cost.

02 / Cross-referenceWhat is the UNS, DIN, JIS and GB equivalent of 2.4819?

Engineers searching for any of the names below are referring to the same chemistry. Jiangyin Jiangnan Metal accepts purchase orders written against any of them and issues a multi-designation material test certificate that lists every specification the heat satisfies.

03 / ChemistryWhat is the chemical composition of 2.4819?

The table below gives the ASTM B564 / B574 limits for UNS N10276, which is the baseline most certificates are written against, alongside the typical mid-band values you will actually see reported on a mill certificate.

Carbon and silicon are the two rows to check first. Earlier Ni-Mo-Cr alloys of this family permitted carbon up to 0.08 % and silicon up to 1 %, and they sensitised in the weld heat-affected zone: carbides precipitated at grain boundaries, depleted the adjacent metal of chromium and molybdenum, and produced knife-line attack in acid service. The low carbon and silicon limits of the present grade were introduced to prevent this. On a 2.4819 certificate these two figures carry more weight than the tensile result.

04 / StandardsHow do ASTM, DIN 17744 and GB limits for 2.4819 differ?

These limits are often presented as identical. They are not. The differences are small and sit almost entirely in the impurity elements, but they matter when one heat has to satisfy a European pressure-equipment package and an ASME package at the same time.

A heat produced to the DIN 17744 phosphorus and sulphur limits will satisfy ASTM B564 and B574, but not the reverse. Our standard practice on 2.4819 is to procure billet to the stricter European limit and cross-certify to both systems on one certificate at no additional cost. Where an order is placed to ASTM alone, a later request to add DIN coverage normally requires a new heat.

05 / MechanicalWhat are the mechanical properties of 2.4819 forgings?

2.4819 is supplied in one condition: solution annealed. The values below are the specification minima that a certificate must meet, and the typical range our forgings actually achieve on the tensile test.

Two points affect design:

• The yield strength is low. At 283 MPa minimum, 2.4819 has approximately the yield strength of annealed 316L. The grade is selected for corrosion resistance rather than strength. Pressure-containing parts sized on allowable stress come out thick, and that thickness, at a density of 8.89 g/cm³ and a nickel-based price, accounts for most of the cost of a C-276 vessel. Where strength and corrosion resistance are both required, Alloy 718 or Alloy 925 are the age-hardenable alternatives, at lower corrosion capability.
• There is no ductile-to-brittle transition. The face-centred-cubic structure retains high impact toughness to cryogenic temperature, so 2.4819 needs no impact-test exemption calculation for low-temperature service, unlike ferritic and martensitic materials used in cryogenic chemical plant.

06 / PhysicalWhat are the physical properties of 2.4819 (density, thermal, magnetic)?

Two of these figures affect fabrication directly. The low thermal conductivity keeps heat at the cutting edge during machining and at the arc during welding, so tool tips and weld pools run hotter than on stainless steel. Combined with the relatively high thermal expansion, this produces more distortion during welding than an equivalent stainless assembly, and fixturing and weld sequence should be planned accordingly.

07 / CorrosionHow corrosion-resistant is 2.4819, and where does it stop working?

2.4819 is specified where a stream combines chlorides, acid and temperature, the conditions that limit stainless steel. Its pitting resistance equivalent number is PREN ≈ 68 using the conventional Cr + 3.3 Mo formula, or ≈ 75 if the tungsten contribution is credited via Cr + 3.3(Mo + 0.5 W). For comparison, 316L sits near 26 and super-duplex near 42. Critical pitting and crevice temperatures for 2.4819 in ASTM G48 testing normally exceed 85 °C, above which the test method rather than the alloy sets the limit.

Intergranular corrosion testing

The standard acceptance test for 2.4819 forgings destined for wet-corrosion service is ASTM G28 Method A (boiling ferric sulphate – 50 % sulphuric acid, 24 h) with a stated maximum corrosion rate, and Method B (boiling mixed acid with ferric chloride) where intermetallic precipitation is the specific concern. A failed G28 result on solution-annealed C-276 nearly always traces back to cooling too slowly from the annealing temperature. For forgings destined for acid service, include G28 in the purchase specification; the test cost is small relative to identifying the problem at commissioning.

08 / Selection2.4819 vs C-22, C-2000, Alloy 59, 625 and 316L

Selection within the Ni-Cr-Mo family turns on whether the environment is reducing or oxidising. Molybdenum addresses reducing conditions, chromium addresses oxidising conditions. 2.4819 is the high-molybdenum, moderate-chromium member of the family, suited to reducing service while still tolerating oxidising excursions.

09 / Sour serviceIs 2.4819 approved for NACE MR0175 / ISO 15156 sour service?

Yes, with conditions. UNS N10276 is listed in ISO 15156-3 among the solid-solution nickel-based alloys acceptable for H₂S-containing environments in oil and gas production. Acceptance is conditional on three things:

1. Delivery condition. Solution annealed. Cold-worked material falls under a different table entry with different limits. This is where most non-conformances originate.
2. Hardness. A maximum of 40 HRC applies to the annealed condition. Properly annealed 2.4819 forgings test around 85–95 HRB, far below that limit, so hardness is rarely the constraint, but it must still be measured and reported.
3. Environmental envelope. The applicable table entry sets limits on temperature, H₂S partial pressure, chloride concentration and the presence of elemental sulphur. Different envelopes apply to different equipment classes, and they are revised between editions of the standard.

10 / Heat treatmentHow is 2.4819 solution annealed?

2.4819 has a single heat treatment. Material that meets the chemistry and tensile requirements but fails in service has usually been annealed or cooled incorrectly.

Why the cooling rate matters. Between roughly 650 °C and 1040 °C, 2.4819 precipitates µ-phase and P-phase intermetallics along grain boundaries. These precipitates draw molybdenum and chromium out of the adjacent matrix, leaving a depleted zone that is attacked preferentially in acid. Material in this state passes its tensile test and then corrodes intergranularly in service. A heavy forging that is air-cooled rather than water-quenched remains in the band too long. Where a certificate does not state the cooling method for a section above about 50 mm, query it.

The same temperature window governs the service limit: continuous operation between 650 °C and 1040 °C should be avoided unless the component can be re-annealed, since the effect on the part is the same as a slow furnace cool.

11 / FabricationHow do you forge, weld and machine 2.4819?

Forging

2.4819 has a narrow hot-working window and high flow stress, requiring roughly twice the deformation load of an austenitic stainless steel at the same temperature. Our working practice:

• Heating: to 1180–1230 °C, in a clean, sulphur-free furnace. Nickel alloys are embrittled by sulphur pick-up from fuel-fired furnaces; ours are gas-fired with controlled sulphur.
• Finishing temperature: not below 950 °C. Below that the alloy work-hardens rapidly and surface cracking risk rises sharply.
• Reheats: more frequent than for steel. A typical 2.4819 ring passes through three to five heats where a comparable stainless ring would need two.
• Forging ratio: minimum 4:1 to break down the cast structure and produce a uniform recrystallised grain size.
• After forging: full solution anneal at 1121 °C with rapid quench. As-forged material is not an acceptable delivery condition.

For buyers this means a higher conversion cost per kilogram than stainless and a longer lead time, both driven by the additional reheats rather than by scheduling.

Welding

• Filler: matching ERNiCrMo-4 bare wire (AWS A5.14) for GTAW and GMAW; ENiCrMo-4 covered electrode (AWS A5.11) for SMAW.
• Preheat: none required. Interpass temperature below approximately 100 °C.
• Heat input: keep low; stringer beads rather than wide weave. Excess heat input holds the HAZ in the precipitation band.
• Post-weld: normally none required. For severe reducing-acid service or heavy restrained joints, a post-weld solution anneal at 1121 °C with rapid quench restores the fully homogeneous condition.
• Cleanliness: stainless or dedicated nickel-alloy brushes and grinding media only. Iron contamination from carbon-steel tooling produces localised rust spots that initiate pitting in service. Degrease thoroughly; sulphur from marker pens, cutting fluid and grease causes hot cracking.

Machining

Machinability is roughly 15–20 % of free-machining B1112 steel. The alloy work-hardens rapidly and conducts heat poorly. Do not allow the tool to dwell, and avoid light spring passes; both work-harden the surface and degrade the following cut.

12 / Failure modesHow does 2.4819 fail in service, and how is each mode prevented?

13 / CapabilityWhat 2.4819 forgings can Jiangyin Jiangnan Metal produce?

Jiangyin Jiangnan Metal Co., Ltd. has operated as an open-die forging factory in Jiangyin, Jiangsu Province since 2008, employing about 460 people including 9 senior and 32 intermediate engineers, and exporting to more than 40 countries. Nickel alloys including 2.4819 are produced on the same presses and ring mills as our stainless and alloy-steel work, with dedicated tooling, handling and storage to prevent iron contamination.

Process flow for a 2.4819 forging

Plant and inspection equipment

14 / QualityWhich standards and quality documents apply to 2.4819 forgings?

15 / OrderingHow do you specify a 2.4819 forging order?

1. State the generic designation. Write UNS N10276 / W.Nr. 2.4819 / NiMo16Cr15W, not the Hastelloy trademark, so every qualified producer can quote.
2. Name the product specification. ASTM B564 or ASME SB-564 for forgings; add DIN 17744 / VdTÜV 400 for a European pressure-equipment package.
3. Define the delivery condition. Solution annealed at 1121 °C with rapid quench, and state whether the anneal is before or after final machining.
4. Specify corrosion testing. ASTM G28 Method A or Method B with a maximum acceptable corrosion rate, for anything entering wet-corrosion service.
5. Specify NDE correctly. Ultrasonic per ASTM A388 or EN 10228-3 with the acceptance class, plus liquid penetrant per ASTM E165. Do not specify magnetic particle testing.
6. Specify certification. EN 10204 3.1 or 3.2, plus a NACE MR0175 / ISO 15156-3 statement and hardness limit if the part enters sour service.
7. Give commercial detail. Quantity, finished dimensions with machining allowance, required date, Incoterm and destination port.

Drawing callout template

MATERIAL:     UNS N10276 / W.Nr. 2.4819 / NiMo16Cr15W
SPECIFICATION: ASTM B564 (ASME SB-564)
              also to satisfy DIN 17744 P and S limits
CONDITION:    Solution annealed 1121 deg C, rapid water quench
HARDNESS:     Report actual; max 100 HRB
CORROSION:    ASTM G28 Method A, rate to be reported and
              not to exceed [ ] mm/y
NDE:          UT per ASTM A388, acceptance class [ ]
              PT per ASTM E165 on all machined surfaces
              MT NOT APPLICABLE - material is non-magnetic
CERTIFICATE:  EN 10204 3.1  [ ] / 3.2 witnessed  [ ]
SOUR SERVICE: NACE MR0175 / ISO 15156-3 compliance statement
              required  [ ] yes  [ ] no
MARKING:      Heat number, specification, our order number,
              low-stress stamp or vibro-etch only

16 / PitfallsTen mistakes engineers make when ordering 2.4819

1. Writing “Hastelloy C-276” on the purchase order. It is a trademark, not a specification. Write UNS N10276 / 2.4819 with the ASTM or DIN specification instead, and open the order to every qualified supplier.
2. Specifying magnetic particle examination. 2.4819 is non-magnetic. Specify liquid penetrant per ASTM E165.
3. Omitting the cooling requirement after annealing. “Solution annealed” without “rapid quench” allows a slow furnace cool, which precipitates the intermetallics the anneal was meant to dissolve.
4. Leaving out ASTM G28. Chemistry and tensile results do not confirm that the anneal was correct. G28 does, at low cost.
5. Sizing the part on stainless-steel allowable stress. With a 283 MPa minimum yield, 2.4819 sections come out thicker than the 316L equivalent, and section thickness on this alloy is costly.
6. Forgetting the density difference. At 8.89 g/cm³, 2.4819 is about 11 % heavier than 316L for the same geometry. Budgets built from a stainless weight estimate come in short.
7. Specifying a hardness ceiling that forces cold work out of scope, then requesting cold-worked material. For NACE service, the solution-annealed entry is the straightforward route; cold-worked material carries different limits.
8. Ignoring iron contamination in handling. Carbon-steel slings, chains, stillages and shared blast media all transfer free iron. Specify iron-free handling and packing in the purchase order.
9. Assuming C-276 is the best choice in every environment. In strongly oxidising service such as nitric acid or hot ferric chloride, Alloy C-22 or Alloy 59 perform better. In hydrofluoric acid, Alloy 400 does.
10. Quoting a lead time from the stainless-steel schedule. Billet availability, additional reheats and the corrosion test package put 2.4819 at 10–14 weeks typical, 14–18 weeks with 3.2 witness or heavy sections.

17 / ApplicationsWhere are 2.4819 forgings used?

Representative project scenarios

18 / GlossaryKey terms used on this page

2.4819

The European Werkstoff (material) number for the nickel-molybdenum-chromium-tungsten alloy also designated UNS N10276 and NiMo16Cr15W.

UNS N10276

The generic Unified Numbering System designation for the same alloy, and the designation to use on purchase orders and drawings.

NiMo16Cr15W

The DIN name for 2.4819, read directly from the nominal chemistry: nickel base, 16 % molybdenum, 15 % chromium, tungsten addition.

Hastelloy® C-276

Registered trademark of Haynes International, Inc. for material they produce to this chemistry. Not a specification.

Solution annealing

Heating to 1121 °C to dissolve carbides and intermetallic phases into solid solution, then quenching rapidly to hold them there. The only heat treatment for 2.4819.

µ-phase and P-phase

Molybdenum-rich intermetallic compounds that precipitate at grain boundaries between roughly 650 °C and 1040 °C, depleting the surrounding matrix and causing intergranular attack.

PREN

Pitting Resistance Equivalent Number, conventionally Cr + 3.3 Mo + 16 N. For 2.4819 it is approximately 68, or about 75 if the tungsten contribution is credited.

ASTM G28

Standard test methods for detecting intergranular attack in wrought nickel-rich alloys. Method A uses boiling ferric sulphate–sulphuric acid; Method B uses a mixed acid with ferric chloride.

ASTM B564

The ASTM product specification for nickel alloy forgings, and the correct specification for forged rings, flanges, discs and tube sheets in N10276.

EN 10204 3.1 / 3.2

Inspection document types. 3.1 is issued by the manufacturer's own independent inspection function; 3.2 is countersigned by a third party or the purchaser's representative.

NACE MR0175 / ISO 15156

The materials standard for H₂S-containing oil and gas production. Part 3 covers corrosion-resistant alloys and lists N10276 with its condition, hardness and environmental limits.

Sensitisation

Loss of corrosion resistance caused by grain-boundary precipitation that depletes the adjacent metal of chromium and molybdenum. The low carbon and silicon limits of 2.4819 exist to prevent it.

ERNiCrMo-4

The AWS A5.14 classification for the matching bare filler wire used to weld 2.4819. The covered-electrode equivalent is ENiCrMo-4 per AWS A5.11.

Iron contamination

Free iron transferred to a nickel-alloy surface by carbon-steel tooling, slings or blast media. It rusts and initiates localised corrosion, and is removed by pickling and passivation.

Forging ratio

The ratio of starting to finished cross-section. A minimum of 4:1 is used on 2.4819 to break down the cast structure and produce uniform recrystallised grain.

19 / FAQFrequently asked questions about 2.4819

20 / ReferencesTechnical references

Chemistry, mechanical, physical and corrosion data on this page are drawn from the published standards and engineering references below. Test results reported on our certificates are independent and traceable to calibrated equipment.

1. ASTM B564/B564M, Standard Specification for Nickel Alloy Forgings, ASTM International, West Conshohocken, PA.
2. ASTM B574/B574M, Standard Specification for Low-Carbon Nickel-Chromium-Molybdenum, Low-Carbon Nickel-Molybdenum-Chromium Alloy Rod, ASTM International.
3. ASTM B575/B575M, Standard Specification for Low-Carbon Nickel Alloy Plate, Sheet and Strip, ASTM International.
4. ASTM B622 / B619 / B626, seamless pipe and tube, welded pipe, and welded tube specifications for nickel alloys, ASTM International.
5. ASTM B366, Standard Specification for Factory-Made Wrought Nickel and Nickel Alloy Fittings, ASTM International.
6. ASTM G28, Standard Test Methods for Detecting Susceptibility to Intergranular Attack in Wrought, Nickel-Rich, Chromium-Bearing Alloys, ASTM International.
7. ASTM A388/A388M, Standard Practice for Ultrasonic Examination of Steel Forgings, ASTM International.
8. ASTM E165/E165M, Standard Practice for Liquid Penetrant Testing for General Industry, ASTM International.
9. ASTM E8/E8M, Standard Test Methods for Tension Testing of Metallic Materials, ASTM International.
10. DIN 17744, Wrought nickel alloys with molybdenum and chromium — Chemical composition, Deutsches Institut für Normung.
11. VdTÜV-Werkstoffblatt 400, NiMo16Cr15W (2.4819), Verband der TÜV.
12. EN 10204, Metallic products — Types of inspection documents, CEN, Brussels.
13. EN 10228-3, Non-destructive testing of steel forgings — Part 3: Ultrasonic testing, CEN.
14. SEP 1921, Ultrasonic testing of steel forgings, Stahl-Eisen-Prüfblatt.
15. NACE MR0175 / ISO 15156-3, Petroleum and natural gas industries — Materials for use in H₂S-containing environments in oil and gas production — Part 3: Cracking-resistant CRAs and other alloys, ISO.
16. ASME Boiler and Pressure Vessel Code, Section II Part B (SB-564, SB-574, SB-575), Part D allowable stresses, and Section VIII Division 1, ASME.
17. AMS 5750, Nickel Alloy, Corrosion and Heat Resistant, Bars, Forgings and Rings, SAE International.
18. AWS A5.14, Specification for Nickel and Nickel-Alloy Bare Welding Electrodes and Rods, and AWS A5.11 for covered electrodes, American Welding Society.
19. ASM Handbook, Volume 2: Properties and Selection: Nonferrous Alloys and Special-Purpose Materials, ASM International, Materials Park, OH.
20. ASM Handbook, Volume 13B: Corrosion: Materials, ASM International.
21. GB/T 15007, Corrosion-resisting alloy — Designation, Standardization Administration of China.

Standards referenced are the latest revisions known at the date of the last page review. For procurement, always cite the revision in force at the contract date. All trademarks are the property of their respective owners.

Related nickel and superalloy grades

• Alloy C-22 / 2.4602
• Alloy C-2000 / N06200
• Alloy C-4 / N06455
• Alloy 59 / N06059
• Alloy B-2 / N10665
• Alloy B-3 / N10675
• Alloy X / N06002
• Alloy 625 / N06625
• Alloy 718 / N07718
• Alloy 825 / N08825
• Alloy 800H / N08810
• Alloy 400 / N04400
• Alloy K-500 / N05500
• 904L / N08904
• All nickel alloy grades