Project Description
Hastelloy C-276 / UNS N10276 is a nickel-molybdenum-chromium-tungsten superalloy engineered for maximum corrosion resistance in the most aggressive oil and gas environments. Developed by Haynes International and standardized under ASTM B574, it is the benchmark material where H₂S, chlorides, and reducing acids coexist at elevated temperatures and pressures.
Hastelloy C-276 — Overview
Hastelloy C-276 (UNS N10276, W.Nr. 2.4819) is arguably the most widely deployed corrosion-resistant alloy in the oil and gas sector. Its balanced Ni-Mo-Cr-W chemistry delivers outstanding resistance to pitting, crevice corrosion, and stress corrosion cracking (SCC) — failure modes that are endemic in sour-gas wells, subsea pipelines, and high-chloride production environments.
The alloy’s low carbon content (≤0.01 wt%) eliminates sensitization in the weld heat-affected zone, allowing components to be used in the as-welded condition without post-weld annealing — a critical advantage in field fabrication. It complies with NACE MR-0175/ISO 15156 for sour-service applications, making it a default choice for HISC-sensitive assemblies.
N10276 Equivalent Grades & Standards
Hastelloy C-276 is recognized under multiple national and international standards. The table below maps the most common designations used by procurement engineers worldwide.
| Standard Body | Designation / Grade | Applicable Form |
|---|---|---|
| UNS (USA) | N10276 | All wrought forms |
| ASTM / ASME | B574 / SB574 (Bar & Forging) B575 / SB575 (Plate/Sheet/Strip) B622 / SB622 (Seamless Pipe & Tube) B619 / SB619 (Welded Pipe) B564 / SB564 (Forgings) |
Bar, Plate, Pipe, Tube, Forging |
| AMS (USA, Aerospace) | AMS 5750 | Bar & Forgings |
| EN / DIN (Europe) | W.Nr. 2.4819 / NiMo16Cr15W DIN 17744 / DIN 17750–17754 |
All wrought forms |
| ISO | NW 2.4819 | Wrought alloy identification |
| GOST (Russia) | ХН65МВУ / ЭП760 | Bar, Sheet |
| JIS (Japan) | NW0276 | Pipe, Plate, Bar |
| NACE | MR-0175 / ISO 15156 Compliant | Sour-service components |
| AWS (Welding) | ERNiCrMo-4 (Wire) / ENiCrMo-4 (Electrode) | Weld consumables |
Oil & Gas Applications of Hastelloy C-276
The following components are machined or forged directly from Hastelloy C-276 bar stock in oil and gas operations worldwide:
- Drill collar inserts
- Logging-while-drilling (LWD) mandrels
- MWD sensor housings
- Perforating gun bodies
- Packer mandrels
- Valve stems & seats
- Gate valve bodies
- Tubing hangers
- Casing head spools
- Actuator shafts
- Subsea tree components
- Umbilical end fittings
- Riser clamp bolts
- Manifold block inserts
- ROV tooling pins
- Heat exchanger tubes & baffles
- Separator vessel internals
- Pump shafts & impellers
- Scrubber spray nozzles
- Pressure vessel nozzles
- Stud bolts & hex nuts
- Flange bolting sets
- Butt-weld fittings
- Socket-weld elbows
- Compression fittings
- H₂S scrubber internals
- Amine contactor trays
- Gas dehydration internals
- Sulfur recovery components
- Injection quill assemblies
Supply Forms & Size Range — Hastelloy C-276 Bar
SHUNFU METAL supplies Hastelloy C-276 in all standard mill and forged forms. Size ranges below reflect our standard stock; non-standard dimensions are available to order with full mill certification.
| Form | Size Range | Condition | Standard |
|---|---|---|---|
| Hot-Rolled Round Bar | Ø 6 – 250 mm | Annealed & Pickled | ASTM B574 |
| Cold-Drawn Round Bar | Ø 3 – 80 mm | Bright Annealed | ASTM B574 |
| Forged Round Bar | Ø 80 – 600 mm | Forged + Annealed | ASTM B564 |
| Hot-Rolled Flat Bar | T 6–150 mm × W 10–400 mm | Annealed & Pickled | ASTM B575 |
| Forged Flat Bar / Block | T 20–300 mm × W 50–800 mm | Forged + Annealed | ASTM B564 |
| Hex Bar | AF 8 – 100 mm | Bright / Pickled | ASTM B574 |
Length: standard 1,000–6,000 mm; cut-to-length and rough-machined blanks available. MTC 3.1 per EN 10204 supplied with every order.
Chemical Composition — ASTM B574 N10276
The composition below conforms to ASTM B574 / UNS N10276 requirements. SHUNFU METAL verifies each heat with OES in-house and third-party ICP analysis before dispatch.
| Element | Ni | Mo | Cr | Fe | W | Co | Mn | Si | V | C | P | S |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Min % | Bal. | 15.0 | 14.5 | 4.0 | 3.0 | — | — | — | — | — | — | — |
| Max % | Bal. | 17.0 | 16.5 | 7.0 | 4.5 | 2.5 | 1.0 | 0.08 | 0.35 | 0.010 | 0.040 | 0.030 |
High Mo (15–17%) + W (3–4.5%) combination provides a PREN of approximately 67, giving exceptional resistance to localized corrosion in chloride-rich environments. Carbon is capped at 0.010% to prevent carbide precipitation during welding.
Mechanical Properties — Hastelloy C-276 Bar (Annealed)
Standard heat treatment: solution anneal at 2050°F (1121°C), rapid water quench. Properties below are at room temperature per ASTM B574 and Special Metals data. SHUNFU METAL performs tensile testing on every production lot using calibrated universal testing machines traceable to NIST standards.
| Form | UTS (MPa) | YS 0.2% (MPa) | Elongation (%) | Hardness |
|---|---|---|---|---|
| Round Bar | 758 min (110 ksi) | 363 min (52.6 ksi) | 40 min (typ. 62) | 88 HRB / ≈200 HB |
| Plate / Sheet | 741–796 (107–115 ksi) | 347–376 (50–54 ksi) | 60–67 | 86–89 HRB |
| Forged Bar (heavy) | ≥ 690 | ≥ 310 | ≥ 30 | ≤ 35 HRC (NACE MR-0175) |
Physical constants: Density 8.89 g/cm³ · Modulus of Elasticity 205 GPa · Thermal Conductivity 10.2 W/m·K at 23°C · Melting Range 1325–1370°C.
How SHUNFU METAL Ensures Quality
We source exclusively from VIM+VAR or AOD-refined heats with full heat-number traceability. Each bar is stamped with heat number, size, and standard — conforming to ASTM A700 identification requirements.
Every heat is re-tested by our in-house OES (spark emission spectrometer) before cutting and shipping. This eliminates material mix-ups — a critical safeguard for sour-service applications.
Forged bars ≥ Ø100 mm undergo 100% UT to ASTM A388 / EN 10228-3 acceptance class S3. Subsurface defects, segregation, and internal cracks are screened before delivery.
Tensile, yield, elongation, and hardness are tested on every heat lot. Mill Test Certificates (MTC 3.1 per EN 10204) are issued with every shipment and are available digitally upon request.