Hastelloy X is a nickel-chromium-iron-molybdenum superalloy renowned for its exceptional performance in extreme high-temperature environments. As a workhorse material in the aerospace and industrial gas turbine industries, it offers a unique combination of high strength, outstanding oxidation resistance, and excellent fabricability. This guide provides a comprehensive overview of its composition, key properties, and critical applications.
What is Hastelloy X?
Hastelloy X is a solid-solution-strengthened nickel-based superalloy. Unlike precipitation-hardened superalloys, its strength comes primarily from the elements dissolved within its nickel matrix, rather than from intermetallic compounds. This gives it remarkable stability and strength at temperatures up to approximately 1200°C (2200°F). Its primary advantage is its ability to withstand severe thermal cycling and oxidizing atmospheres while maintaining structural integrity.
Hastelloy X Chemical Composition
Hastelloy X’s excellent high-temperature performance is due to its chemical composition.
| Element | Content (%) | Role |
| Nickel (Ni) | Balance | Provides the fundamental austenitic matrix and corrosion resistance. |
| Chromium (Cr) | 20.5 – 23.0 | Essential for superior resistance to oxidizing environments at high temperatures. |
| Iron (Fe) | 17.0 – 20.0 | A major alloying element that contributes to strength and helps control costs. |
| Molybdenum (Mo) | 8.0 – 10.0 | Provides solid-solution strengthening and enhances creep resistance. |
| Cobalt (Co) | 0.5 – 2.5 | Adds to the alloy’s high-temperature strength and stability. |
| Tungsten (W) | 0.2 – 1.0 | Contributes to solid-solution strengthening. |
| Carbon © | 0.05 – 0.15 | Kept at a controlled level for carbide formation and strength. |
| Manganese (Mn) | 1.0 (max) | Acts as a deoxidizer. |
| Silicon (Si) | 1.0 (max) | Improves castability and provides some oxidation resistance. |
Key Properties
Hastelloy X is chosen for demanding applications due to its distinctive set of properties:
- Exceptional High-Temperature Strength:It retains excellent tensile and creep-rupture strength at temperatures where many other alloys fail.
- Outstanding Oxidation Resistance:Forms a protective, adherent oxide scale that resists spalling under cyclic heating conditions.
- Excellent Fabricability:It is one of the easiest-to-weld superalloys and can be readily formed using both hot and cold working techniques.
- Good Stress-Corrosion Cracking Resistance:Offers reliable performance in various high-temperature service environments.
Applications and Industrial Uses
The unique properties of Hastelloy X make it indispensable in several high-tech sectors:
- Gas Turbine Engines:Used for combustor cans, transition ducts, afterburner parts, and turbine exhaust components.
- Industrial Furnaces:Ideal for furnace baskets, retorts, and other components exposed to high-temperature oxidizing atmospheres.
- Chemical Processing:Used in equipment for high-temperature nitriding and carburizing.
- Nuclear Power:Employed in certain high-temperature reactor core components.
- Aerospace:Used for thrust reverser assemblies and other hot-section aircraft engine parts.
Physical and Mechanical Properties Tables
Physical Properties
| Property | Value |
| Density | 8.22 g/cm³ (0.297 lb/in³) |
| Melting Point | 1260 – 1355 °C (2300 – 2470 °F) |
| Modulus of Elasticity | 196 GPa (28.4 x 10⁶ psi) |
Mechanical Properties (Typical, Solution Annealed)
| Temperature (°C) | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) |
| Room Temp | 755 | 345 | 43 |
| 540 | 620 | 260 | 50 |
| 650 | 515 | 240 | 50 |
| 870 | 185 | 105 | 65 |
*Note: These are typical values. Properties can vary based on heat treatment and product form.*
International Equivalents and Standards
Hastelloy X is a trademark name of Haynes International, but it is specified under various international standards.
| Standard / Designation | Specification |
| UNS Number | N06002 |
| AMS (Aerospace) | 5754 (Sheet, Plate, Strip) |
| ASTM | B435 (Plate, Sheet, Strip), B619 (Welded Pipe), B622 (Seamless Pipe) |
| EN (Europe) | 2.4665 (NiCr22FeMo) |
Processing and Fabrication
Hastelloy X is known for its excellent fabricability. It is typically supplied in the solution-annealed condition.
- Forming:Can be cold-formed using standard processes, but requires more power than carbon steel. Hot forming is recommended for complex shapes.
- Welding:It has excellent weldability. Common methods include Gas Tungsten Arc Welding (GTAW/TIG) and Gas Metal Arc Welding (GMAW/MIG). No preheating or post-weld heat treatment is typically required.
- Machining:It is a high-strength alloy and should be machined using sharp tools, rigid setups, and positive feeds to avoid work hardening.
At Daxun Alloys Co., Ltd., we understand the critical nature of these materials. We offer precision cutting, forming, and machining services for Hastelloy X to ensure it meets the exacting tolerances required for your high-performance applications.
Common Product Forms
Hastelloy X is available in a range of standard product forms to meet diverse manufacturing needs.
- Plate and Sheet:For structural components, shrouds, and liners.
- Bar and Rod:For fasteners, shafts, and fittings.
- Pipe and Tube:For high-temperature fluid and gas handling systems.
- Wire and Welding Consumables:Specifically designed for welding the alloy.
Frequently Asked Questions (FAQ)
- What is the main difference between Hastelloy X and Inconel 625?
While both are nickel-based superalloys, Hastelloy X is optimized for superior strength and oxidation resistance at higher temperatures (up to 1200°C). Inconel 625 offers better corrosion resistance in a wider range of aggressive chemical environments but has lower high-temperature strength. - Is Hastelloy X magnetic?
No, Hastelloy X has an austenitic structure and is typically non-magnetic. - Can Hastelloy X be heat-treated to increase its strength?
It is not an age-hardening alloy. Its strength is derived from solid-solution strengthening and work-hardening. The standard heat treatment is a solution anneal to restore its properties after forming.
Conclusion
Hastelloy X remains a critical material for any application involving extreme heat and oxidative stress. Its unparalleled combination of strength, stability, and fabricability makes it a top choice for the most demanding environments in aerospace, power generation, and industrial manufacturing.
For your next high-temperature project, trust the expertise of Daxun Alloys Co., Ltd. We supply premium-grade Hastelloy X and offer comprehensive processing solutions to meet your exact specifications. Contact us today for a detailed quote and to discuss how we can support your requirements.
*For official technical data: Haynes International – Hastelloy X Page*
