Alloy X,Inconel HX Bar(Round bar, Flat bar),UNS N06002

Alloy X,Hastelloy X Wire,UNS N06002

Introduction to Alloy X (Hastelloy X Wire, UNS N06002) – Versatile High-Temperature Superalloy Series

Alloy X, commercially known as Hastelloy X and classified under UNS N06002, is a nickel-chromium-iron-molybdenum-cobalt superalloy engineered for exceptional performance in extreme high-temperature environments (up to 1200°C/2192°F). Its unique chemistry balances high-temperature strength, oxidation resistance, and thermal fatigue resistance—making it ideal for applications exposed to continuous or cyclic heat, such as aerospace engine components and industrial furnace systems. As specified, Alloy X is available in a comprehensive range of product forms: Bar (Round bar, Flat bar), Ribbon, Wire, Rods, Tube, Pipe, Foil, Plate, Sheet, Strip, and Forging Stock. This versatility allows it to meet diverse design and manufacturing needs across industries where reliability under thermal stress is critical.

1. Chemical Composition (Typical, wt%)

The chemical composition of UNS N06002 adheres to strict industry standards including ASTM B366 (for nickel-alloy flanges/fittings), ASTM B435 (for nickel-alloy wire), and ASME SB366, ensuring consistent high-temperature performance across all product forms. The typical composition is as follows:

Element

Content Range (wt%)

Function

Nickel (Ni)

47.0 - 50.0

Serves as the alloy matrix, stabilizing the austenitic structure and enhancing ductility at high temperatures; improves resistance to molten salt corrosion.

Chromium (Cr)

21.0 - 23.5

Forms a dense, adherent chromium oxide (Cr₂O₃) layer, providing superior oxidation and sulfidation resistance at temperatures up to 1200°C.

Iron (Fe)

17.0 - 20.0

Enhances hot workability (critical for forging, rolling, and extrusion) and reduces alloy cost without compromising high-temperature strength.

Molybdenum (Mo)

8.0 - 10.0

Boosts high-temperature creep strength and resistance to localized corrosion (e.g., pitting) in chloride-containing environments.

Cobalt (Co)

0.5 - 2.5

Improves thermal fatigue resistance (key for cyclic high-temperature applications like engine components) and stabilizes the alloy’s microstructure at extreme heat.

Carbon (C)

0.05 - 0.15

Enhances grain boundary strength, improving creep and stress rupture performance at 1000 - 1200°C; controlled to avoid excessive carbide precipitation.

Manganese (Mn)

≤ 1.0

Aids in deoxidation during melting and improves cold workability for thin forms (e.g., foil, ribbon).

Silicon (Si)

≤ 1.0

Promotes formation of a protective silica layer, supplementing chromium oxide for enhanced oxidation resistance in high-temperature air.

Phosphorus (P)

≤ 0.04

Limited to prevent brittleness, especially in welded joints of tubes and pipes exposed to thermal cycling.

Sulfur (S)

≤ 0.03

Minimized to avoid hot cracking during fabrication (essential for wire drawing and forging) and reduce corrosion susceptibility.

Tungsten (W)

≤ 0.5

Trace element to further enhance high-temperature strength without compromising ductility.

2. Physical Properties

Alloy X exhibits stable physical properties across its primary operating temperature range (-200°C to 1200°C), ensuring consistent performance for both cryogenic pre-assembly and extreme heat service. Key properties (uniform across all product forms) are:

Property

Value

Test Condition

Density

8.30 g/cm³

Room temperature (25°C)

Melting Point Range

1320 - 1370°C

-

Thermal Expansion Coefficient

13.1 × 10⁻⁶/°C

20 - 100°C; 17.8 × 10⁻⁶/°C (20 - 1000°C)

Thermal Conductivity

11.5 W/(m·K)

100°C; 25.1 W/(m·K) (1000°C)

Electrical Resistivity

1.25 × 10⁻⁶ Ω·m

Room temperature (25°C); 1.60 × 10⁻⁶ Ω·m (1000°C)

Modulus of Elasticity

205 GPa

Room temperature (tensile); 140 GPa (1000°C)

Poisson’s Ratio

0.30

Room temperature

Curie Temperature

≈ -196°C

Below this temperature, the alloy is weakly ferromagnetic (irrelevant for high-temperature applications).

Stress Rupture Strength

140 MPa

1000 hours at 800°C; 40 MPa (1000 hours at 1000°C)

Oxidation Resistance

Weight gain ≤ 0.1 g/m²·h

1000°C in air (after 1000 hours, no spallation of oxide layer)

3. Production Process (Tailored for Multiform Products)

The manufacturing of Alloy X into its diverse product forms requires precise process control to preserve high-temperature properties, dimensional accuracy, and surface integrity. Below is a unified production framework with form-specific optimizations:

3.1 Raw Material Melting & Casting (Base for All Forms)

Melting: High-purity raw materials (nickel, chromium, molybdenum, etc.) are melted via vacuum induction melting (VIM) followed by argon oxygen decarburization (AOD). This dual process eliminates gaseous impurities (O₂ < 20 ppm, N₂ < 40 ppm) and adjusts carbon content to target levels—critical for avoiding grain boundary embrittlement in high-temperature service.

Casting: Molten alloy is cast into:

Ingots (800 - 3000 kg) for bars, rods, and forging stock.

Slabs (15 - 60 mm thick) for plates, sheets, and strips.

Blooms (120 - 350 mm diameter) for tubes and pipes.

All cast forms undergo homogenization annealing at 1180 - 1230°C for 8 - 10 hours to eliminate chemical segregation and refine grain structure.

3.2 Form-Specific Hot & Cold Processing

3.2.1 Bars (Round/Flat), Rods, & Forging Stock

Hot Forging: Ingots are hot-forged at 1080 - 1180°C using hydraulic presses to form round bars (diameter: 15 - 400 mm) or flat bars (thickness: 8 - 120 mm, width: 30 - 600 mm). Forging stock is shaped into near-net components (e.g., turbine discs, furnace doors) via closed-die forging, with controlled cooling to prevent grain coarsening.

Hot Rolling: Smaller rods (diameter: 6 - 25 mm) are produced via hot rolling at 1050 - 1150°C, followed by air cooling.

Cold Finishing: Precision bars undergo cold drawing (round bars) or cold rolling (flat bars) to achieve tight tolerances (±0.03 mm) for critical machining applications, then stress-relieved at 700 - 800°C to reduce residual stresses.

3.2.2 Plates, Sheets, Strips, & Foil

Hot Rolling: Slabs are hot-rolled at 1050 - 1150°C into plates (thickness: 6 - 150 mm) or continuous coils (for sheets/strips). Intermediate annealing (1000 - 1050°C, water-quenched) is performed to maintain ductility during rolling.

Cold Rolling: Sheets (thickness: 0.8 - 6 mm) and strips (thickness: 0.15 - 1.5 mm, width: 15 - 300 mm) are cold-rolled in multiple passes. Foil (thickness: 0.02 - 0.15 mm) requires ultra-fine cold rolling with frequent intermediate annealing (980 - 1030°C) to avoid work hardening—critical for preserving flexibility in thin gauges.

Flatness Correction: Plates and sheets undergo precision leveling (roller or press leveling) to achieve flatness ≤ 0.08 mm/m, essential for aerospace component assembly.

3.2.3 Tubes & Pipes

Seamless Tubes: Blooms are extruded at 1100 - 1200°C into tube blanks (outer diameter: 25 - 250 mm, inner diameter: 12 - 230 mm), then pierced via the Mannesmann process to create seamless tubes. Cold drawing (for precision tubes) refines dimensions to outer diameter: 8 - 200 mm, wall thickness: 0.8 - 30 mm, with post-drawing annealing at 1000 - 1050°C.

Welded Tubes/Pipes: For large-diameter pipes (outer diameter > 250 mm), Alloy X strip is formed into a cylinder and welded via TIG or laser welding. Post-weld annealing at 1050 - 1100°C ensures the weld zone matches the base metal’s corrosion and high-temperature properties.

3.2.4 Wire & Ribbon

Wire Production: Blooms are hot-rolled into wire rods (diameter: 6 - 18 mm) at 1050 - 1150°C. Wire rods are then cold-drawn through diamond dies into final wire diameters (0.15 - 8 mm) with intermediate annealing (980 - 1050°C, 20 - 40 minutes) to maintain ductility—critical for smooth wire feeding in welding or heating element applications.

Ribbon Production: Wire rods or thin flat stock are cold-rolled into ribbon (thickness: 0.08 - 0.8 mm, width: 2 - 80 mm), with surface polishing to achieve Ra ≤ 0.3 μm for applications like heating coils or electrical contacts.

3.3 Uniform Heat Treatment

All Alloy X products undergo solution annealing—the key step for optimizing high-temperature performance. The process involves heating to 1150 - 1200°C for 20 - 60 minutes (duration scales with thickness: 20 min for foil, 60 min for thick plates), followed by rapid water quenching. This dissolves unwanted precipitates (e.g., carbides), produces a uniform fine-grained austenitic microstructure, and maximizes oxidation resistance and creep strength.

3.4 Surface Finishing & Quality Inspection

Surface Treatment:

Bars/Rods: Grinding (Ra ≤ 0.6 μm) or polishing (Ra ≤ 0.2 μm for aerospace-grade) to remove scale and defects.

Plates/Sheets: Pickling (nitric-hydrofluoric acid solution) to eliminate oxide layers, then passivated (optional chromate treatment) for enhanced corrosion resistance in chemical environments.

Tubes/Pipes: Internal honing (for high-flow applications) and external polishing to reduce friction in fluid transport; welded pipes undergo weld bead grinding for smooth surfaces.

Wire/Foil: Electrochemical cleaning to remove drawing lubricants and oxides, ensuring surface purity for welding or thin-film applications.

Quality Control:

Chemical Analysis: Optical emission spectroscopy (OES) and inductively coupled plasma mass spectrometry (ICP-MS) to verify elemental composition compliance.

Mechanical Testing: Tensile strength (≥700 MPa at room temperature, ≥200 MPa at 1000°C), elongation (≥35% at room temperature), and hardness (≤240 HB).

High-Temperature Testing: Creep rupture testing (1000 hours at 1000°C) and oxidation testing (1000 hours at 1200°C) to validate performance.

Non-Destructive Testing: Ultrasonic testing (for bars/plates/tubes) to detect internal defects; eddy current testing (for wire/foil) for surface flaws; pressure testing (for pipes) at 2× design pressure.

4. Product Applications (By Form & Industry)

Alloy X’s combination of high-temperature strength, oxidation resistance, and form versatility makes it indispensable in industries requiring reliable performance under extreme heat. Key applications are organized by product form:

4.1 Bars (Round/Flat), Rods, & Forging Stock

Aerospace & Defense:

Round bars: Machined into jet engine combustor liners, afterburner components, and rocket nozzle throats (resist 1000 - 1200°C exhaust gases).

Forging stock: Forged into gas turbine blades, turbine discs, and missile guidance system housings (withstand thermal cycling and mechanical stress).

Industrial Furnaces: Flat bars fabricated into furnace heating element supports and hearth rails (operate in air or inert gas at 900 - 1100°C).

Chemical Processing: Rods machined into agitator shafts for high-temperature polymer reactors (resist molten plastic and catalyst corrosion).

4.2 Plates, Sheets, Strips, & Foi

Aerospace:

Plates: Used to manufacture aircraft engine flame holders and heat shields (protect against radiant heat up to 1150°C).

Sheets: Formed into exhaust system components for supersonic aircraft (resist thermal fatigue from rapid temperature changes).

Energy Generation:

Strips: Welded into heat exchanger cores for concentrated solar power (CSP) plants (operate in heat transfer fluids at 800 - 900°C).

Foil: Used as thermal barrier coatings for nuclear reactor auxiliary components (resist high-temperature coolant corrosion).

Metallurgy: Plates constructed into molten metal handling equipment (e.g., aluminum casting molds) due to resistance to molten metal attack.

4.3 Tubes & Pipes

Aerospace: Seamless tubes used as fuel lines and cooling air ducts in jet engines (transport fluids at 800 - 1000°C).

Chemical & Petrochemical:

Pipes: Transport high-temperature syngas (CO + H₂) in gasification plants (resist sulfidation and carbon deposition).

Tubes: Used in ethylene cracking furnaces (operate at 1100°C to break down hydrocarbons into ethylene).

Energy: Welded pipes for biomass combustion boilers (resist high-temperature ash and flue gas corrosion).

4.4 Wire & Ribbon

Aerospace: Wire (0.2 - 1.0 mm diameter) used as heating elements in aircraft de-icing systems (operate at 500 - 700°C) and as thermocouple sheaths for engine temperature monitoring.

Industrial Heating: Ribbon formed into resistance heating coils for high-temperature furnaces (used in metal heat treatment, operate at 900 - 1100°C in air).

Electronics: Fine wire (0.15 - 0.3 mm) used as high-temperature electrical connectors in automotive exhaust sensors (resist 600 - 800°C exhaust gases).

Conclusion

Alloy X (Hastelloy X Wire, UNS N06002) is a premier high-temperature superalloy, distinguished by its exceptional thermal stability, oxidation resistance, and diverse product portfolio. From heavy forging stock for turbine components to ultra-thin foil for thermal coatings, it meets the demands of aerospace, energy, and chemical industries where performance under extreme heat is non-negotiable. Its strict manufacturing controls and compliance with global standards ensure reliability across all applications. For custom requirements—such as ultra-precision wire (down to 0.05 mm diameter), large-diameter seamless pipes (up to 500 mm), or specialty heat treatments—tailored production processes are available to align with specific high-temperature challenges.

Packing of Standard Packing: 

Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 856 gallon liquid totes Special package is available on request.