Hastelloy X (UNS N06002): High-Temperature Oxidation Resistant Alloy for Aerospace

AMS 5536 / ASTM B435 · Published: 2026-06-01 · Updated: 2026-06-02

Hastelloy X (UNS N06002) is a nickel-chromium-iron-molybdenum alloy designed for exceptional oxidation resistance and high-temperature strength up to 1,200°C. It is the most widely used wrought nickel alloy for aerospace gas turbine hot-section components: combustor cans, transition ducts, afterburner components, and tail cone assemblies. The alloy's 22% chromium content forms a protective Cr2O3 scale; 9% molybdenum provides solid-solution strengthening at elevated temperatures; and 18.5% iron reduces raw material cost compared to more nickel-rich superalloys like Inconel 718.

Fabrication: Hastelloy X is readily formed in the solution-annealed condition (1,177°C, rapid air cool or water quench). It is weldable by GTAW (TIG), GMAW (MIG), and resistance welding — matching filler metal (AMS 5798) must be used. Post-weld stress relief at 1,080°C for 1 hour is recommended to minimize distortion. The alloy cannot be age-hardened — all strengthening is by solid solution, and high-temperature strength derives from the inherent creep resistance of the FCC (face-centered cubic) nickel matrix rather than precipitate strengthening. For applications requiring higher strength at temperature, precipitation-hardened superalloys (Inconel 718, Waspaloy) are specified for rotating components, while Hastelloy X remains the standard for static hot-section sheet metal components.

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