What are the differences between Inconel 718 alloy and Haynes 282 alloy?
Inconel 718 typically exhibits higher strength at low temperatures and better room-temperature mechanical properties; while Haynes 282 offers superior high-temperature strength and creep resistance, making it more suitable for applications above 650°C (1200°F). Haynes 282 also offers better weldability and machinability, but its higher strain rate sensitivity and higher cost (due to its higher cobalt and molybdenum content) may make it more difficult to process.
Why is Inconel 718 difficult to machine?
Inconel 718 nickel-based superalloys exhibit excellent properties at high temperatures, making them widely used in the aerospace, marine, and automotive industries. However, Inconel 718 has poor thermal conductivity and is prone to rapid strain hardening, resulting in poor machinability and poor surface finish.
For medium- to high-temperature structural components requiring excellent long-term creep resistance, thermal stability above approximately 650°C (1200°F), and good weldability, Haynes 282 is generally the better choice. For applications requiring extremely high room-temperature and medium-temperature yield/tensile strength, a wide availability of various forging/forging forms, and long-standing experience in the oil and gas and aerospace industries, Inconel 718 remains the preferred choice. Ultimately, the suitable alloy depends on the operating temperature, required creep life, manufacturing process (welding-intensive or forging-based), and cost/supply constraints.
Haynes 282 (UNS N07208) and Inconel 718 (UNS N07718) are both nickel-based superalloys developed specifically for high-temperature applications, but their designs cater to different performance requirements.
Haynes 282 is a γ′ phase-strengthened forged superalloy designed to balance high creep resistance at high temperatures with good weldability and machinability. It is suitable for hot gas passage components, advanced steam and supercritical carbon dioxide (s-CO₂) power cycles, and other applications requiring long creep life at temperatures above 650°C.
Inconel 718 is a precipitation-hardening nickel-chromium-iron alloy (primary hardener: γ″ phase Ni₃Nb) exhibiting excellent strength from low temperatures to approximately 650°C. Its combination of machinability, high yield/tensile strength under aging conditions, and a mature supply chain has led to its widespread use in aerospace, oil and gas, and tool manufacturing.
Chemical composition (typical nominal values)
| Element | Haynes 282 (typical, wt%) | Inconel 718 (typical, wt%) |
|---|---|---|
| Nickel (Ni) | ~57 (balance) | ~50–55 (balance) |
| Chromium (Cr) | ~20 | ~17–21 |
| Cobalt (Co) | ~10 | ≤1 (trace to none) |
| Molybdenum (Mo) | ~8.5 | ~2.8–3.3 |
| Niobium (Nb, sometimes reported as columbium) | - (low; Nb not primary hardener) | ~4.75–5.5 |
| Titanium (Ti) | ~2.1 | ~0.65–1.15 |
| Aluminum (Al) | ~1.5 | ~0.2–0.8 |
| Iron (Fe) | ~1.5 max | remainder / balance |
| Carbon (C) | ~0.06 | ≤0.08 |
| Boron (B), Mn, Si | trace | trace |
Mechanical performance summary
Representative tensile/yield figures (age-hardened condition; typical ranges)
| Alloy | Typical 0.2% yield (ksi / MPa) | Typical UTS (ksi / MPa) | Notes |
|---|---|---|---|
| Haynes 282 (age-hardened sheet data) | ~112.9 ksi (≈779 MPa) | ~172.8 ksi (≈1191 MPa) | Haynes published sheet tensile figures for age-hardened material. |
| Inconel 718 (cold-rolled/aged / sheet/forgings vary) | typical range ~140–190 ksi (≈965–1310 MPa) depending on product & cold work | typical UTS ~190–215 ksi (≈1310–1480 MPa) | Special Metals tensile tables show variation by product and processing; 718 often reaches higher peak yield in the aged & cold-worked states. |
Machinability and Weldability
Inconel 718: More difficult to machine than Haynes 282, primarily due to its higher strength and greater sensitivity to strain rates.
Haynes 282: Offers better weldability and machinability compared to many other high-temperature alloys with similar creep strength.
Corrosion Resistance
Inconel 718: Corrosion resistance depends on the environment; it performs better than Haynes 282 in some alkaline media, but is more susceptible to corrosion in acidic environments (e.g., HCl).
Haynes 282: Offers better corrosion resistance than Inconel 718 in some acidic media due to the formation of a denser passivation film.
Why Choose Gnee Nickel Alloy (Supplier Example)?
✅ Large stock of Inconel alloy tubes/bars/plates/fittings/coils, fast shipping.
✅ Factory direct sales, highly competitive prices, excellent value for money.
✅ Comprehensive quality assurance: Material Testing Certificate (MTC), chemical composition certificate, and mechanical property certificate.
✅ Value-added services: slitting, cutting, polishing, surface treatment.
✅ Worldwide shipping, secure and reliable packaging, and provision of export-required documents.
Email: ss@gneemetal.com
Gnee Steel is a supplier of Inconel 718 alloy, offering a wide range of products including: seamless pipe (sizes: 4-219 mm; thickness: 0.5-20 mm); welded pipe (sizes: 5.0-1219.2 mm; thickness: 0.5-20 mm); plates (thickness: 0.1 to 100 mm; width: 10-2500 mm); strips; alloy round bars (diameter: 3-800 mm); flat bars (thickness: 2-100 mm; width: 10-500 mm); hexagonal bars (size: 2-100 mm); wire rods; and extruded profiles. We collaborate with steel mills to provide our customers with Inconel 718 alloy products that meet or exceed numerous leading industry standards, including ASTM, ASME, SAE, AMS, ISO, DIN, EN, and BS standards.
Gnee Steel stocks and sells Inconel 718, pipes, plates, strips, round bars, flat bars, forged billets, hexagonal steel, wire rods, and extruded profiles. Please feel free to contact us at ss@gneesteel.com for a quote.
