Hastelloy Alloys
Hastelloy X (UNS N06002) — Composition, Properties & Supply
Hastelloy X (UNS N06002) is a solid-solution Ni-Cr-Fe-Mo superalloy combining oxidation resistance to 1200 °C with useful high-temperature strength. It resists combustion-gas corrosion and thermal fatigue, making it a classic material for aero-engine combustors, afterburners and industrial furnaces.
What is the chemical composition of Hastelloy X?
| Element | Symbol | Content (wt%) |
|---|---|---|
| Ni | Ni | Balance |
| Cr | Cr | 20.5–23.0 |
| Fe | Fe | 17.0–20.0 |
| Mo | Mo | 8.0–10.0 |
| Co | Co | 0.50–2.50 |
| W | W | 0.20–1.00 |
| C | C | 0.05–0.15 |
| Si | Si | ≤ 1.00 |
| Mn | Mn | ≤ 1.00 |
| B | B | ≤ 0.008 |
Values are typical specification limits. Actual heat analysis is reported on the EN 10204 3.1 mill test certificate supplied with each shipment.
What are the mechanical properties of Hastelloy X?
| Property | Value | Note |
|---|---|---|
| Tensile strength | ≥ 655 MPa | Room temperature |
| Yield strength (0.2% offset) | ≥ 240 MPa | Room temperature |
| Elongation | ≥ 35 % | Gauge length 50 mm / 4D |
| Hardness | ≤ 200 HB | Brinell / Rockwell |
What are the physical properties of Hastelloy X?
| Property | Value |
|---|---|
| Density | 8.22 g/cm³ |
| Melting range | 1260–1355 °C |
| Thermal conductivity | 9.1 W/m·K |
| Elastic modulus | 205 GPa |
| Maximum service temperature | 1200 °C |
What are the key characteristics of Hastelloy X?
- Oxidation resistance to 1200 °C plus carburisation and nitriding resistance
- Outstanding combustion-gas corrosion and thermal fatigue resistance
- Balanced high-temperature strength and formability
- Good weldability with ERNiCrMo-2 filler
Where is Hastelloy X used?
- Aero-engine combustors, afterburners and tailpipes
- Industrial gas turbine transition ducts and flame tubes
- Industrial furnace rollers, radiant tubes and muffles
- Reformer and cracking furnace components
- Heat-treat fixtures and baskets
Which standards and specifications cover Hastelloy X?
Which standards cover Hastelloy X forgings and bar?
Hastelloy X is ordered by product form, not under one catch-all specification. Forgings and forging stock fall under ASTM B564, the nickel alloy forging specification, with the UNS N06002 composition limits carried from ASTM B435. Wrought bar uses ASTM B572; plate, sheet and strip use ASTM B435; seamless tube uses ASTM B622.
That split is why a forging enquiry should name the form. Asking for "Hastelloy X to ASTM B435" on a closed-die forging leaves the acceptance criteria undefined, because B435 governs flat product, not forged shape.
| Product form | Standard | Note |
|---|---|---|
| Forgings and forging stock | ASTM B564 | Nickel alloy forgings; grain flow and forging ratio apply |
| Plate, sheet and strip | ASTM B435 | Flat rolled product, solution annealed |
| Bar and rod | ASTM B572 | Hot worked bar |
| Seamless pipe and tube | ASTM B622 | Seamless product |
| Welded tube | ASTM B626 | Welded product |
Hastelloy X is a solid-solution alloy: it is supplied solution annealed and is not precipitation hardened. Holding it between about 650 °C and 870 °C during fabrication or service precipitates secondary phases and costs ductility, so heat-affected fabrication steps are followed by a re-anneal where the drawing requires it.
What product forms are available?
Frequently asked questions
How does Hastelloy X differ from Inconel 601?
Both resist high-temperature oxidation, but X carries 8–10% molybdenum and 17–20% iron, giving markedly better hot strength and combustion-gas corrosion resistance plus oxidation resistance to 1200 °C. 601 costs less and is more cost-effective for furnace parts in clean air without combustion-gas attack.
Which standards cover Hastelloy X forgings?
Hastelloy X forgings and forging stock are ordered to ASTM B564, the nickel alloy forging specification, with the UNS N06002 composition limits from ASTM B435. Bar is specified separately under ASTM B572, and plate, sheet and strip under ASTM B435. Naming the form on the enquiry is what selects the correct standard.
Is Hastelloy X supplied in the solution-annealed condition?
Yes. Hastelloy X is a solid-solution alloy and is supplied solution annealed; it is not precipitation hardened. Any intermediate ageing at 650–870 °C during fabrication reduces ductility and should be avoided or followed by a re-anneal.
Need Hastelloy X bar, tube, plate or forgings?
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