Nickel-chromium-iron-molybdenum grade, Alloy X offers outstanding strength and corrosion resistance at temperatures up to 1093°C.
Alloy X is a solid-solution-strengthened nickel-based alloy designed for excellent strength, fabricability and oxidation resistance in extreme thermal conditions. Its high molybdenum, chromium and iron content provides strong corrosion resistance in both oxidising and reducing environments, especially those containing carburising gases.
The alloy retains structural integrity in thermal cycling environments and has good weldability with matching filler metals. Alloy X is widely used in jet engine combustion components, heat-treating systems and high‑temperature industrial plant equipment.
We stock Alloy X in a range of forms, including coil, plate, sheet, round bar and welding wire, available for fast dispatch and certified to international standards. Explore the dropdowns below to view available specifications and add products to your enquiry basket.
Alloy X demonstrates excellent metallurgical stability, corrosion resistance and mechanical strength in prolonged high-temperature service. It performs reliably in challenging combustion environments and furnace conditions.
| % | Cr | Mo | Co | W | Al | Ti | B | C | Fe | Mn | Si | P | S | Cu | Ni |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Min | 20.5 | 8 | 0.5 | 0.2 | - | - | - | 0.05 | 17 | - | - | - | - | - | - |
| Max | 23 | 10 | 2.5 | 1 | 0.5 | 0.15 | 0.01 | 0.15 | 20 | 1 | 1 | 0.04 | 0.03 | 0.5 | Balance |
Alloy X is engineered for long‑term stability in extreme heat. Its balance of nickel, chromium, molybdenum and iron allows it to resist carburisation, oxidation, thermal cycling and fatigue in some of the most demanding conditions. The alloy can be welded using conventional methods with matching filler wire. After severe forming, annealing at 1177°C (15 minutes per 1/8” thickness) followed by rapid air cooling is recommended to regain mechanical and structural performance.
Due to its molybdenum content, Alloy X should not be exposed to temperatures above 1204°C, where it may undergo catastrophic oxidation.
| Mechanical &Physical Properties | 21C° | 538°C | 649°C | 760°C | 871°C | 982°C |
|---|---|---|---|---|---|---|
| Ultimate Tensile Strength /MPa | 765.3 | 613.6 | 572.2 | 462 | 310.3 | - |
| 0.2% Yield Strength /MPa | 379.2 | 248.2 | 241.3 | 234.4 | 193 | - |
| Elongation % | 44 | 49 | 54 | 53 | 58 | - |
| Coefficient of Thermal Expansion /mm/m°C x 10-6 | - | 15.1 | 15.5 | 15.8 | 16.2 | 16.6 |
| Thermal Conductivity /kcal/(hr.m.°C) | - | 16.8 | 19 | 20.7 | 22.6 | 24.4 |
| Modulus of Elasticity/ x105 MPa | 2.07 | 1.79 | 1.72 | 1.59 | 1.52 | 1.38 |
| Temperature °C | 649°C | 816°C | 982°C |
|---|---|---|---|
| 100 Hours, ksi | 48 | 14 | 4 |
| 10,000 Hours, ksi | 34 | 10 | 2 |
Alloy X is a top choice for high-temperature engineering applications where thermal stress, oxidation and mechanical loading occur together. It’s widely used in the aerospace, power generation and thermal processing sectors.
Used for heat shields, combustion liners and structural supports in extreme heat service.
Ideal for forming transition ducts, furnace linings and jet engine insulation layers.
Preferred for precision components such as fasteners, shafts, and turbine mounts.
Used for constructing or repairing high-temperature alloy assemblies in industrial furnaces or gas turbines.
It’s commonly used in jet engines, heat treatment equipment, aircraft heaters, combustion systems, and industrial furnaces, thanks to its high-temperature stability and resistance to oxidation and carburising environments.
Alloy X offers reliable performance up to 1093°C. It should not be used above 1204°C due to the potential for oxidation failure.
No, Alloy X is non-magnetic in the annealed condition, making it suitable for instrumentation and high-temperature electrical applications.
Yes. Alloy X has good weldability using matching filler wire. Post-weld annealing may be necessary for high-performance applications.
Alloy 625 offers better corrosion resistance in seawater and aqueous environments, but Alloy X outperforms in extreme heat and oxidising or carburising conditions.
Looking for a trusted supplier of Alloy X? NeoNickel provides extensive stock across Europe, fast turnaround, and technical expertise for high-temperature alloy projects. Add a product to your enquiry basket or contact our specialists for tailored support.
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