Hastelloy X
2.4665Nickel-chromium-iron-molybdenum solid-solution superalloy — exceptional combination of oxidation resistance, fabricability, and high-temperature strength. NOT age-hardenable (solid-solution only). Oxidation-resistant to 1200°C, good ductility after 16000h at 650-870°C. Outstanding formability and weldability for a superalloy. Used for gas turbine combustor cans, transition ducts, afterburners, furnace hardware, and petrochemical process equipment.
International equivalents
| Flag | Standard | Country | Grade | Number | Match |
|---|---|---|---|---|---|
| 🇺🇸 | UNS | USA | UNS N06002 | N06002 | REF |
| 🇪🇺 | EN | Europe | NiCr22Fe18Mo / 2.4665 | 2.4665 | 100% |
| 🇺🇸 | AMS | USA | AMS 5536 (sheet) / AMS 5754 (bar) | — | 100% |
Sources: ASTM B435, DIN 17744, AMS 5536
Chemical composition comparison (wt%)
Side-by-side: Hastelloy X (UNS) (ASTM B435) vs NiCr22Fe18Mo / 2.4665 (EN)
| Element | Hastelloy X (UNS) | NiCr22Fe18Mo / 2.4665 (EN) | Overlap |
|---|---|---|---|
| C | 0.05–0.15% | — | — |
| Si | 0–1% | — | — |
| Mn | 0–1% | — | — |
| Cr | 20.5–23% | — | — |
| Mo | 8–10% | — | — |
| Ni | — | — | — |
| W | 0.2–1% | — | — |
| B | 0–0.008% | — | — |
| Co | 0.5–2.5% | — | — |
| Fe | 17–20% | — | — |
Mechanical properties
Solution Treated
| Property | Value | Unit |
|---|---|---|
| Tensile Strength | 690–760 | MPa |
| Yield Strength | 275–345 | MPa |
| Elongation | 35–45 | % |
| Elastic Modulus | ≥ 205 | GPa |
| Density | ≥ 8.22 | g/cm3 |
Heat treatment
| Process | Temperature | Medium | Holding Time | Notes |
|---|---|---|---|---|
| solution_treatment | 1150–1177 °C | rapid air or water | — | Not age-hardenable — solution treated only |
Compatibility verdict
Hastelloy X and NiCr22Fe18Mo / 2.4665: 100% composition match
Close equivalents but NOT identical.
Related materials
Hastelloy C-22
2.4602Improved version of Hastelloy C-276 with better resistance to oxidizing media and higher chromium. Considered the most versatile Ni-Cr-Mo alloy for chemical processing. Resists both oxidizing and reducing acids, chlorides, and mixed media. Used for flue gas desulfurization, pharmaceutical, and universal chemical processing.
Alloy 20 / Carpenter 20
2.4660Austenitic Ni-Fe-Cr alloy specifically developed for sulfuric acid resistance. Nb-stabilized against sensitization. Cu addition gives outstanding resistance to H2SO4 at all concentrations up to 80%. Used for sulfuric acid piping, heat exchangers, mixing tanks, pickling equipment, and pharmaceutical processing.
Nimonic 80A
2.4952Nickel-chromium age-hardenable alloy with Ti + Al for gamma-prime strengthening. Developed originally for gas turbine blades. Good creep resistance to ~700°C. Used for exhaust valves, springs at elevated temperatures, nuclear engineering fasteners, and gas turbine components. ≈ UNS N07080.
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