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HASTELLOY C276 FASTENERS — DATASHEET, CHEMICAL COMPOSITION, MECHANICAL PROPERTIES & SUPPLY
Ananka Fasteners is a premier manufacturer and global exporter of Hastelloy C276 Fasteners (UNS N10276 / W.Nr. 2.4819). Engineered for the most aggressive service conditions—from boiling reducing acids to subsea manifolds—this nickel-molybdenum-chromium-tungsten superalloy delivers uncompromising structural integrity where conventional stainless steels fail.
The defining breakthrough of UNS N10276 is its strict limitation on carbon (0.01% max) and silicon (0.08% max), which completely suppresses chromium carbide precipitation. Every fastener is produced in-house using CNC machining, hot forging, and precision cold heading, backed by EN 10204 Type 3.1 certification and 100% traceability.
■ Download Technical Datasheet
■ Material Test Certificates
Every lot shipped by Ananka is accompanied by an EN 10204 Type 3.1 MTC, documenting actual chemical analysis, mechanical test results, PMI verification, and dimensional inspection data. EN 10204 Type 3.2 certification is available on request.
■ Hastelloy C276 Material Specifications
| Material Type | Nickel-Molybdenum-Chromium-Tungsten Wrought Superalloy |
|---|---|
| UNS / Werkstoff | N10276 / 2.4819 |
| EN Chemical Designation | NiMo16Cr15W |
| Density | 8.89 g/cm³ (0.321 lb/in³) |
| Melting Range | 1325 – 1370 °C (2415 – 2500 °F) |
| Size Range | Metric: M2 to M160 | Imperial: 3/16" to 4" Custom machined lengths up to 1500 mm available. |
| Thread Types | UNC, UNF, 8UN, Metric Coarse, Metric Fine, BSW, BSF |
■ Chemical Composition of Alloy C276 (per ASTM B574)
Heavy solute atoms (Mo, W) are dissolved into the primary nickel lattice, impeding dislocation movement and granting the material immense structural integrity and unparalleled localized corrosion resistance.
| Ni | Mo | Cr | Fe | W | Co | Mn | V | C | Si | P | S |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Bal. | 15.0 – 17.0 | 14.5 – 16.5 | 4.0 – 7.0 | 3.0 – 4.5 | 2.50 Max | 1.0 Max | 0.35 Max | 0.01 Max | 0.08 Max | 0.04 Max | 0.03 Max |
■ Mechanical Properties
Values per ASTM F468 and ASTM B574. The massive gap between yield and ultimate tensile strength ensures bolted joints stretch before catastrophically rupturing.
| Property | Minimum (per ASTM F468) | Typical Range |
|---|---|---|
| Ultimate Tensile Strength (UTS) | 690 MPa (100 ksi) | 758 – 965 MPa (110 – 140 ksi) |
| Yield Strength (0.2% Offset) | 283 MPa (41 ksi) | 310 – 358 MPa (45 – 52 ksi) |
| Elongation | 25% | 40% – 60% |
| Hardness (Rockwell C) | 20 HRC Min | 20 – 32 HRC Max |
■ International Equivalent Grades
| Standard / Region | Designation |
|---|---|
| UNS (Universal) | N10276 |
| Werkstoff / DIN | 2.4819 |
| EN Designation | NiMo16Cr15W |
| Common Trade Name | Alloy C276, Hastelloy C-276 |
■ Key Industrial Applications
With a PREN exceeding 45, Hastelloy C276 offers robust protection against severe reducing media, oxidizing environments, and complete immunity to chloride-induced stress corrosion cracking.
- Chemical Processing (CPI): Organic chloride synthesis reactors, boiling acetic/formic acid reactors, and hot contaminated sulfuric acid evaporators.
- Power Generation (FGD): Scrubber stack liner fasteners handling hot, highly acidic slurries containing sulfur compounds.
- Oil & Gas: Subsea manifolds and downhole tooling requiring NACE MR0175 / ISO 15156 compliance for sour gas (H₂S) service.
- Pulp, Paper & Pharmaceuticals: Digester vessel bolting, bleach plant flanges, and high-temperature steam sterilization autoclaves.
■ Range of Hastelloy C276 Fasteners
| Bolts & Screws | Nuts & Washers | Studs & Rods |
|---|---|---|
| Hex Bolts / Socket Head Cap Screws | Standard Hex Nuts / Heavy Hex Nuts | Fully Threaded Studs (DIN 976) |
| Flange Bolts / U-Bolts / Set Screws | Flat / Spring / Belleville Washers | Threaded Rods / Custom Studs |
■ Dedicated Product Pages
- Hastelloy C276 Bolts: Heavy hex, flange, and socket head configurations from M6 to M100.
- Hastelloy C276 Nuts: Standard hex, heavy hex, and prevailing torque locknuts per ASTM F467.
- Hastelloy C276 Washers: Flat, spring, and Belleville washers for critical load distribution and thermal compensation.
- Hastelloy C276 Stud Bolts: Precision-machined stud bolts per ASME B16.5 for critical flanged connections.
- Hastelloy C276 Threaded Rods: Fully-threaded fastening solutions for aggressive chemical and offshore service.
■ Torque & Installation Guidelines (UNC Threads)
To counteract galling, the application of high-temperature nickel-compatible anti-seize lubricants is functionally mandatory. Pneumatic impact wrenches must never be used.
| Nominal Diameter | Threads Per Inch (UNC) | Target Torque — Dry (ft-lbs) | Target Torque — Lubricated (ft-lbs) |
|---|---|---|---|
| 1/2" | 13 | 40.2 | 30.1 |
| 5/8" | 11 | 79.9 | 60.0 |
| 3/4" | 10 | 142.0 | 107.0 |
| 1" | 8 | 343.0 | 257.0 |
■ Why Source from Ananka
- In-House Manufacturing: Full control from bar stock through hot forging, cold heading, and CNC machining.
- 100% Traceability: Every fastener is traceable from the vacuum induction melt source to final packing.
- Rigorous PMI Testing: Every production lot is verified by handheld XRF to confirm alloy chemistry before dispatch.
- ISO 9001:2015 Certified: Stringent quality management covering incoming inspection, in-process NDT, and final checks.
- Custom Speeds: Non-standard sizes, special thread forms, and custom-length studs produced rapidly.
■ Frequently Asked Questions
Q1: What is Hastelloy C276?
It is a nickel-molybdenum-chromium-tungsten wrought superalloy (UNS N10276) known for universal corrosion resistance. Its ultra-low carbon and silicon content completely suppresses grain boundary carbide precipitation during welding.
Q2: What ASTM standards cover these fasteners?
Hastelloy C276 fasteners are covered under ASTM F468 (bolts/studs), ASTM F467 (nuts), and ASTM B574 (raw rod/bar stock).
Q3: Is Hastelloy C276 compliant with NACE MR0175?
Yes. Solid-solution nickel-based alloys like C276 are broadly approved for high-H₂S sour gas environments, provided material hardness remains below 35 HRC.
Q4: Why is thread galling a concern?
C276's high ductility and extreme shear strength make it susceptible to cold welding (galling) under clamping load. Prevention requires anti-seize lubrication and strictly manual or low-speed hydraulic tightening.