Hastelloy C-276 – UNS N10276
Low-carbon nickel-molybdenum-chromium-tungsten alloy
Ni-Mo-Cr-W alloy (16Mo-15.5Cr-3.75W) with very low carbon and silicon, which reduces grain-boundary precipitation in the HAZ and allows use in the as-welded condition. It is the reference for reducing and mixed chloride media: contaminated HCl and H₂SO₄, ferric/cupric chloride, hypochlorite and chlorine dioxide. It is limited in hot concentrated nitric acid.
Designations and equivalents
| System | Designation |
|---|---|
| UNS | N10276 |
| W.Nr./EN | 2.4819 – NiMo16Cr15W |
| DIN | NiMo16Cr15W |
| JIS | NW0276 |
| Trade names | Hastelloy C-276 (Haynes), Nicrofer 5716 hMoW (VDM), Inconel C-276 (Special Metals), Alloy C276 |
Standards by product form
| Form | Standard |
|---|---|
| Bar | ASTM B574 |
| Forging | ASTM B564; B462 (flanges and fittings) |
| Plate | ASTM B575 |
| Tube | ASTM B622 (seamless), B619/B626 (welded) |
Tolerances and HS codes
- Forged bars (round and square): machining allowance from 2 mm (Ø 6–16 mm) to 24 mm (Ø 400–500 mm) on the diameter. E.g. Ø 100–125 mm finished: +7 mm, tolerance +6 / −0 (length up to 3,500 mm).
- Forged discs: allowance of 4 to 9 mm on the diameter and 3 to 11 mm on the height, plus-only tolerance.
- Cutting and machining: band saw −0 / +5 to +15 mm on length; waterjet +10 % of thickness on the diameter (min. 2 mm); machined parts −0 / +2 to +5 mm on the diameter. See the full tables (INF 002 and INF 003, the same for every alloy).
| Form | NCM (Brazil, 8 digits) | HS (international, 6 digits) | HTS (USA, 10 digits)* | CN (European Union, 8 digits)* |
|---|---|---|---|---|
| Forged bar | 7505.12.10 | 7505.12 | 7505.12.3000 | 7505 12 00 |
| Hot-rolled bar | 7505.12.10 | 7505.12 | 7505.12.3000 | 7505 12 00 |
| Plate (> 10 mm, width ≥ 600 mm) | 7506.20.00 | 7506.20 | 7506.20.3000 | 7506 20 00 |
| Seamless pipe | 7507.12.00 | 7507.12 | 7507.12.0000 | 7507 12 00 |
| Welded pipe | 7507.12.00 | 7507.12 | 7507.12.0000 | 7507 12 00 |
| Flange and fitting | 7507.20.00 | 7507.20 | 7507.20.0000 | 7507 20 00 |
Tariff class: nickel alloy (by chemical composition, under the Chapter 72 Notes and Section XV Note 5).
*: US and EU codes for reference. NCM per current legislation (General Rules of Interpretation, Notes to Chapters 72, 74 and 75 and Section XV Note 5). Confirm the final code with your customs broker according to the item size and finish. HS = first 6 digits of the NCM.
Chemical composition (%)
ASTM B574 / B564 (UNS N10276)
| Element | Range (%) |
|---|---|
| Ni | balance (≈ 57) |
| Mo | 15.0 – 17.0 |
| Cr | 14.5 – 16.5 |
| Fe | 4.0 – 7.0 |
| W | 3.0 – 4.5 |
| Co | ≤ 2.5 |
| Mn | ≤ 1.0 |
| V | ≤ 0.35 |
| Si | ≤ 0.08 |
| C | ≤ 0.010 |
| P | ≤ 0.04 |
| S | ≤ 0.03 |
Mechanical properties
solution annealed (ASTM B564 / B574)
| Property | Value |
|---|---|
| Yield strength (0.2%) | ≥ 283 MPa |
| Tensile strength | ≥ 690 MPa |
| Elongation | ≥ 40% |
| Hardness (ISO 15156-3) | no limit in the solution-annealed condition; limit only for cold-worked material (check table A.14)* |
Typical physical properties
| Property | Value |
|---|---|
| Density | 8.89 g/cm³ |
| Melting range | 1,323 – 1,371 °C |
| Modulus of elasticity | 205 GPa |
| Thermal conductivity (20 °C) | 10.2 W/m·K |
| Thermal expansion (20–100 °C) | 11.2 µm/m·K |
| Electrical resistivity | 130 µΩ·cm |
Heat treatment, welding and machining
| Item | Usual practice |
|---|---|
| Service temperature | An alloy for aqueous corrosion, from cryogenic up to ~675 °C in the ASME allowable stress tables; corrosive service should stay below ~650 °C. Prolonged exposure between ~650 and 1,040 °C precipitates μ and P phases and reduces corrosion resistance. |
| Heat treatment | Solution annealing at ≈ 1,120 °C with rapid cooling (water). Hot forming between 870 and 1,230 °C, followed by a new solution anneal. Not age hardenable. |
| Welding | Good weldability by GTAW, GMAW and SMAW. Consumables: AWS A5.14 ERNiCrMo-4 and AWS A5.11 ENiCrMo-4 (or over-alloyed ERNiCrMo-10). Do not use oxyacetylene or submerged arc. |
| Machining | Difficult: work hardens quickly; use carbide, low speed, firm feed and abundant coolant. |
Filler metal for welding
The wire composition is usually not identical to the material: each page explains why.
Typical applications
- FGD scrubbers, ducts and dampers
- Reactors, exchangers and evaporators with acidic chlorides
- ClO₂ bleaching in pulp and paper
- Oil and gas wells with H₂S, CO₂ and chlorides (severe sour service)
- Effluent treatment and incineration
- Pharmaceuticals and fine chemicals
Alternatives: C22 in oxidizing (HNO₃, Fe³⁺, wet chlorine) and mixed media; B-3 for pure HCl without oxidizers; 625 in moderate media, at lower cost; C-4 when there is long thermal exposure.
Hastelloy C-276: complete guide
What Hastelloy C-276 is
Hastelloy C-276 belongs to the family of nickel alloys, in the nickel-chromium-molybdenum group. Tungsten of 3 to 4.5% is an alloying element in solid solution, not "a coating layer", and together with molybdenum gives resistance to pitting, crevice corrosion and reducing media; chromium gives passivity in moderately oxidizing media. With carbon up to 0.010% and silicon up to 0.08%, the alloy can be welded without losing corrosion resistance in the heat-affected zone, which made it the reference of its class.
Mechanical properties
Solution annealed, ASTM B574 requires a minimum yield strength of 283 MPa, minimum tensile strength of 690 MPa and minimum elongation of 40%. The alloy does not harden by heat treatment, only by cold work, and work hardens faster than austenitic stainless steels.
Heat treatment, forming and welding
Supplied solution annealed at about 1,120 °C and water quenched. Prolonged exposure between 650 and 1,040 °C precipitates intermetallic phases that reduce toughness and corrosion resistance, so that range is for fabrication, not service. Forging is done at 870 – 1,230 °C with subsequent solution annealing. Welding is done with ERNiCrMo-4 consumables, without preheating and normally without post-weld heat treatment; oxyacetylene and submerged arc are not recommended. Dustre performs solution annealing in its own furnaces as part of its heat treatment service.
Corrosion and limits of use
C-276 resists hydrochloric and sulfuric acid, acid chlorides, chlorinated solvents, formic and acetic acids, acetic anhydride, wet chlorine, hypochlorites, ferric and cupric chlorides, seawater and brines, without pitting, crevice corrosion or stress corrosion cracking, with an equivalent PREN of around 70 to 75. The relatively low chromium is the limitation: in hot concentrated nitric acid and strongly oxidizing media C-22 is the better choice.
Applications
Acid gas scrubbers and ducts, flue gas stacks and reheaters, evaporators and reactors in the chemical and pharmaceutical industry, pulp bleaching equipment, valve and pump components in hot chlorides, effluent treatment and oil well parts in sour service.
Supply forms and Dustre services
Round bars and blocks forged in open die, cut to size on a band saw, with rough or finish machining, solution annealing or annealing in our own furnaces and hardness, tensile and impact testing. All material is supplied with a 3.1 inspection certificate and heat traceability.
Frequently asked questions
What is the chemical composition of Hastelloy C-276?
Per ASTM B574 / B564 (UNS N10276): Ni balance (≈ 57); Mo 15.0 – 17.0; Cr 14.5 – 16.5; Fe 4.0 – 7.0; W 3.0 – 4.5; Co ≤ 2.5.
Which standards cover Hastelloy C-276?
Bar: ASTM B574. Forging: ASTM B564; B462 (flanges and fittings). Plate: ASTM B575. Tube: ASTM B622 (seamless), B619/B626 (welded).
Up to what temperature can Hastelloy C-276 be used?
An alloy for aqueous corrosion, from cryogenic up to ~675 °C in the ASME allowable stress tables; corrosive service should stay below ~650 °C. Prolonged exposure between ~650 and 1,040 °C precipitates μ and P phases and reduces corrosion resistance.
Which materials can replace Hastelloy C-276?
C22 in oxidizing (HNO₃, Fe³⁺, wet chlorine) and mixed media; B-3 for pure HCl without oxidizers; 625 in moderate media, at lower cost; C-4 when there is long thermal exposure.
