Hastelloy C276 / Alloy 2.4819 Nickel Alloy Round Bar / Disc / Circle Hot Rolled and Forged C276 Round Rod
Hastelloy C276 (UNS N10276, W. Nr. 2.4819) is a premium nickel-molybdenum-chromium alloy renowned for its exceptional corrosion resistance in harsh environments, particularly against oxidizing and reducing media. The hot-rolled and forged round bars, discs, and circles of this alloy leverage optimized manufacturing processes to enhance mechanical strength, structural integrity, and dimensional precision, making them ideal for critical industrial applications where reliability and durability are non-negotiable.
1. Chemical Composition (Key Parameters)
The superior performance of Hastelloy C276 stems from its precisely controlled chemical composition, which balances nickel (the base element) with alloying elements to resist corrosion and maintain mechanical stability. Below is the typical composition per international standards:
| Element | Content Range (%) | Function |
| Nickel (Ni) | 54.0 - 60.0 | Base metal; provides ductility, toughness, and resistance to stress corrosion cracking |
| Chromium (Cr) | 14.5 - 16.5 | Enhances oxidation resistance and resistance to sulfuric/nitric acid |
| Molybdenum (Mo) | 15.0 - 17.0 | Critical for resistance to reducing media (e.g., hydrochloric acid) and pitting corrosion |
| Tungsten (W) | 3.0 - 4.5 | Complements molybdenum to boost resistance to crevice corrosion and localized attack |
| Iron (Fe) | ≤ 5.0 | Improves workability during hot rolling/forging without compromising corrosion resistance |
| Carbon (C) | ≤ 0.010 | Minimized to prevent carbide precipitation (avoids intergranular corrosion at high temperatures) |
| Silicon (Si) | ≤ 0.08 | Controls oxide formation and enhances casting/forging quality |
| Manganese (Mn) | ≤ 1.0 | Aids in deoxidation during manufacturing; maintains alloy ductility |
| Phosphorus (P) | ≤ 0.040 | Restricted to avoid brittleness and reduce corrosion risks |
| Sulfur (S) | ≤ 0.030 | Minimized to prevent hot cracking during forging and improve corrosion resistance |
2. Mechanical & Physical Properties
Hot-rolled and forged Hastelloy C276 round bars exhibit enhanced mechanical properties compared to cast or cold-worked variants, thanks to grain refinement during thermal processing.
2.1 Mechanical Properties (Typical Values for Hot-Rolled/Forged Bars, Annealed Condition)
| Property | Unit | Value (Annealed, 25°C/77°F) |
| Tensile Strength (UTS) | MPa | ≥ 790 |
| Yield Strength (0.2% Offset) | MPa | ≥ 380 |
| Elongation (in 50mm) | % | ≥ 40 |
| Hardness (Brinell, HB) | - | ≤ 210 |
| Impact Toughness (Charpy V-Notch) | J | ≥ 100 (at 25°C) |
2.2 Physical Properties
| Property | Unit | Value (at 25°C/77°F unless noted) |
| Density | g/cm³ | 8.89 |
| Melting Range | °C | 1325 - 1370 |
| Thermal Conductivity | W/(m·K) | 11.8 (at 100°C) |
| Coefficient of Thermal Expansion (CTE) | μm/(m·K) | 12.4 (20 - 100°C) |
| Electrical Resistivity | Ω·mm²/m | 1.37 |
| Modulus of Elasticity | GPa | 205 |
3. Manufacturing Process: Hot-Rolled vs. Forged
The hot-rolled and forged processes are critical to optimizing the performance of Hastelloy C276 round bars:
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Hot-Rolled Round Bars: Produced by heating the alloy billet to 1150 - 1250°C (above its recrystallization temperature) and rolling it through successive dies to achieve the desired diameter (typically 6mm - 300mm). This process improves ductility, refines grain structure, and ensures uniform dimensional accuracy. Hot-rolled bars are cost-effective for standard applications.
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Forged Round Bars/Discs/Circles: Manufactured by applying high pressure to heated billets (1100 - 1200°C) using presses or hammers, shaping them into round rods, discs (thickness: 10mm - 500mm; diameter: 50mm - 1000mm), or circles. Forging eliminates internal defects (e.g., porosity), enhances mechanical strength (especially impact toughness), and aligns grain flow with the part’s stress direction. Forged products are preferred for high-pressure, high-temperature (HPHT) applications.
4. International Standards & Specifications
Hastelloy C276 round bars, discs, and circles comply with globally recognized standards to ensure consistency and quality:
| Standard Organization | Standard Number | Application Scope |
| ASTM International | ASTM B574 | Nickel alloy rod, bar, and wire (primary standard for hot-rolled/forged bars) |
| ASTM International | ASTM B622 | Nickel alloy plate, sheet, and strip (reference for discs/circles) |
| ASME | ASME SB574 | Boiler and pressure vessel code (for HPHT applications) |
| DIN (Germany) | DIN EN 10095 | Heat-resistant steels and nickel alloys (includes 2.4819) |
| ISO | ISO 9723 | Nickel and nickel alloys — Rods and bars |
| JIS (Japan) | JIS H4551 | Nickel and nickel alloy bars |
5. Equivalent Grades
Hastelloy C276 is marketed under different designations worldwide, depending on regional standards. Below are its key equivalent grades:
| Regional System | Grade Designation | Corresponding Standard |
| UNS (USA) | N10276 | ASTM B574, ASME SB574 |
| W. Nr. (Germany) | 2.4819 | DIN EN 10095, DIN 17750 |
| BS (UK) | NA 44 | BS 3074 (Part 3) |
| JIS (Japan) | NW 276 | JIS H4551 |
| GOST (Russia) | KhN68MVTYu | GOST 9668 |
| EN (Europe) | NiCr21Mo14W | EN 10095 |
6. Key Performance Advantages
Hastelloy C276 round bars stand out for their unique combination of properties, making them superior to many other nickel alloys:
- Exceptional Corrosion Resistance: Resists both oxidizing (e.g., nitric acid, seawater) and reducing (e.g., hydrochloric acid, sulfuric acid) media. It also withstands pitting, crevice corrosion, and stress corrosion cracking (SCC) in chloride-rich environments.
- High-Temperature Stability: Maintains mechanical strength and corrosion resistance up to 1093°C (2000°F), making it suitable for high-heat applications (e.g., furnace components).
- Excellent Fabricability: Hot-rolled and forged variants offer good ductility, allowing for bending, welding, and machining (with carbide tools) to meet custom part requirements.
- Low Carbide Precipitation: The low carbon content minimizes the formation of chromium carbides during welding or heat treatment, eliminating intergranular corrosion risks.
7. Applications
Hastelloy C276 round bars, discs, and circles are widely used in industries where corrosion resistance and high-temperature performance are critical:
- Chemical Processing: Reactors, heat exchangers, valves, and pump shafts (for handling acids, solvents, and corrosive slurries).
- Oil & Gas: Downhole components, wellhead equipment, and pipeline systems (resists sour gas, brines, and chloride-induced corrosion).
- Pharmaceutical & Food Processing: Vessels, mixers, and sanitary fittings (complies with FDA standards; resists cleaning agents and sterilization processes).
- Aerospace & Defense: Jet engine combustion chambers, turbine blades, and missile components (withstands high heat and aggressive fuels).
- Environmental Engineering: Flue gas desulfurization (FGD) systems, wastewater treatment equipment, and incinerator parts (resists acidic flue gases and toxic chemicals).
- Power Generation: Boiler tubes, steam turbines, and nuclear plant components (handles high pressure, high temperature, and coolant corrosion).
