Hastelloy X Alloy | N06002 | 2.4665 | 1200°C Oxidation Resistant | Fushun Metal

Hastelloy X / N06002 / 2.4665 — Introduction

Hastelloy X, designated UNS N06002 and Werkstoff Nr. 2.4665, is a solid-solution-strengthened nickel-chromium-iron-molybdenum alloy engineered specifically for sustained high-temperature service in oxidizing, reducing, and neutral atmospheres up to 1200°C. Unlike precipitation-hardenable superalloys such as Rene 41 and Nimonic 90A, Hastelloy X derives its elevated-temperature strength entirely from solid-solution hardening by molybdenum (8–10%), cobalt (0.5–2.5%), and tungsten (0.2–1.0%) within a high-chromium (20.5–23%) nickel matrix stabilized by 17–20% iron. This composition delivers an exceptional combination of oxidation resistance, fabricability, and weldability unmatched by any single competing grade: it can be formed, welded, and placed into service without the complex multi-step precipitation-hardening heat treatments required by gamma-prime-strengthened alloys, yet retains useful tensile and creep-rupture strength at temperatures where most stainless steels have long since exceeded their structural limits. With a continuous service rating of 900°C and short-term capability to 1080°C, Hastelloy X is the industry-standard material for gas turbine combustion chambers, afterburner components, industrial furnace radiant tubes and rollers, and high-temperature gas-cooled nuclear reactor internals worldwide.

At Fushun Metal, Hastelloy X is manufactured through a fully integrated triple-melt route under one roof. VIM primary melting under high vacuum ensures precise control of the reactive strengthening elements—particularly the narrow tungsten window and the critical chromium level that governs oxidation resistance to 1200°C. The VIM electrode undergoes VAR, where controlled directional solidification eliminates macro-segregation of molybdenum and tungsten—two heavy elements prone to micro-banding in less controlled solidification—producing chemically homogeneous electrode stock essential for consistent high-temperature mechanical properties. For aerospace combustion hardware, nuclear reactor internals, and critical industrial furnace components where long-term microstructural stability under thermal cycling is non-negotiable, we deploy PESR as the final stage, achieving deep desulfurization and oxide refinement through argon-shielded reactive slag for maximum thermal-fatigue resistance.

Every heat is processed, solution-annealed, quenched, and tested within Fushun Metal’s certified quality management system—ISO 9001 for manufacturing process control and AS9120B for aerospace distribution traceability. Full digital traceability links each production lot from melt heat number through remelt sequence, hot-working reduction ratio, and final solution-annealing batch. Standard deliverables include room-temperature and elevated-temperature tensile testing, stress-rupture testing per ASTM E139 at design-relevant temperatures, grain size verification per ASTM E112, ultrasonic inspection, and chemical re-verification by optical emission and LECO combustion analysis. Mill test certificates to EN 10204 3.1 or 3.2 accompany every shipment.

Equivalent Grades of Hastelloy X Across International Standards

Hastelloy X is codified under multiple national and international specification systems. The table below maps its designations and governing standards across major markets. Fushun Metal certifies to all listed specifications and can dual-certify heats where required.

Applications of Hastelloy X

Hastelloy X is the default specification wherever thin-gauge sheet metal fabrications must simultaneously withstand gas temperatures exceeding 900°C, resist oxidation and carburization from combustion products, and survive thousands of thermal cycles without embrittlement or distortion. Its solid-solution-strengthened microstructure eliminates the strain-age cracking risk that plagues gamma-prime-hardened alloys during welding and repair, making it the dominant combustion-section material in both aero and industrial gas turbines.

Hastelloy X — Supply Range by Fushun Metal

Fushun Metal stocks and processes Hastelloy X across all major mill forms from a single integrated facility. Our in-house 6000-ton hydraulic open-die press, 1800-ton precision radial forger (GFM), and multi-stand 850/550/350/250 rolling mills enable a broad dimensional envelope without outsourcing—ensuring uninterrupted lot traceability from melt to delivery under ISO 9001 and AS9120B. All material is supplied in the solution-annealed condition per ASTM B435 / B572 / AMS 5536 (typically 1150–1177°C, rapid air or water cool). Hot-working is performed at 1170°C maximum with finishing temperatures above 950°C. The alloy’s excellent weldability permits fabrication by GTAW, GMAW, and resistance welding using ERNiCrMo-2 filler wire or ENiCrMo-2 electrodes; low heat input and interpass temperature control below 100°C are recommended. Post-weld stress relief at 870°C for 30–60 minutes may be applied. Mill test certificates to EN 10204 3.1 or 3.2 accompany every shipment.

Chemical Composition of Hastelloy X — ASTM B435 / AMS 5536

All heats produced by Fushun Metal are melted via VIM+VAR or VIM+PESR and verified against the composition limits below by optical emission spectrometry and LECO combustion analysis. Full chemical certificates are issued with every shipment under ISO 9001 and AS9120B quality management. The 20.5–23% chromium content is the primary driver of oxidation resistance to 1200°C, forming a dense, adherent Cr₂O₃ scale. The combination of molybdenum (8–10%), cobalt (0.5–2.5%), and tungsten (0.2–1.0%) provides solid-solution strengthening that is retained to temperatures well above the gamma-prime solvus of precipitation-hardened alloys, eliminating the risk of over-aging or strain-age cracking during fabrication and repair welding.

Mechanical Properties of Hastelloy X — Per Product Form & Temperature

Hastelloy X is a solid-solution-strengthened alloy; all properties are developed through solution annealing at 1150–1177°C followed by rapid air or water cooling. The alloy is not hardenable by precipitation heat treatment—this is its principal practical advantage over Rene 41, Waspaloy, and other gamma-prime-strengthened grades for fabricated sheet-metal structures. Room-temperature properties below represent minimum guaranteed values per ASTM B435 and B572. Elevated-temperature tensile and stress-rupture data are provided as typical values for design reference.

Fushun Metal performs all solution annealing in-house under calibrated furnace controls. The alloy exhibits exceptional ductility retention after prolonged high-temperature exposure: elongation values above 30% are maintained after 16,000 hours at 650°C, 760°C, and 870°C, demonstrating freedom from embrittling phase precipitation. Hot-working temperature: 1170°C maximum, finish above 950°C. Cold-working requires intermediate annealing due to the alloy’s high work-hardening rate. Welding consumables: ERNiCrMo-2 (AWS A5.14) filler wire; ENiCrMo-2 (AWS A5.11) electrode.

Physical constants: Density 8.28 g/cm³; Melting range 1260–1355°C; Hardness ≤241 HB (annealed condition); Modulus of elasticity 205 GPa at 20°C; Thermal conductivity 14.4 W/m·K at 20°C; Coefficient of thermal expansion 13.5 μm/m·°C (20–100°C). Continuous maximum service temperature: 900°C (long-term), 1080°C (short-term). Oxidation resistance: rated to 1200°C in air. The alloy is non-magnetic.