Hastelloy X / UNS N06002 / 2.4665 Round Bar: Hot Rolled and Forged
Bars Diameter 5 - 350mm
1. Introduction and Overview
Hastelloy® X (UNS N06002, Werkstoff Nr. 2.4665) is a
nickel-chromium-iron-molybdenum alloy renowned for its exceptional
strength and oxidation resistance at high temperatures. It is one
of the most widely used nickel-based superalloys for service in
severely demanding thermal environments. This product information
sheet details the specifications, properties, and applications of
our high-quality Hastelloy X round bars, available in hot-rolled
and forged conditions, with diameters ranging from 5mm to 350mm.
The primary reason for selecting Hastelloy X is its outstanding
combination of fabrication characteristics and high-temperature
performance. Unlike many other high-temperature alloys that can be
challenging to weld and form, Hastelloy X offers good
manufacturability while delivering reliable service in temperatures
ranging from cryogenic levels up to 1200°C (2200°F). Our production
process for these round bars—utilizing hot rolling for smaller
diameters and precision forging for larger sections—ensures a
homogeneous microstructure, minimal segregation, and optimal
mechanical properties throughout the cross-section.
2. Key Characteristics and Advantages
The superior performance of Hastelloy X stems from its carefully
balanced chemical composition. The key characteristics that make it
a material of choice for critical applications include:
Excellent Oxidation Resistance: The high chromium content (approx.
22%) forms a dense, adherent chromium oxide (Cr₂O₃) scale that
protects the underlying metal from further degradation in oxidizing
atmospheres up to 1175°C (2150°F).
High-Temperature Strength: Solid solution strengthening from
molybdenum and tungsten provides remarkable creep rupture strength
and tensile strength at elevated temperatures, where many stainless
steels begin to soften significantly.
Good Fabricability: Despite its high strength, Hastelloy X can be
readily formed, machined, and welded using standard techniques,
making it suitable for complex component fabrication.
Resistance to Reducing Atmospheres: The significant molybdenum
content (approx. 9%) confers excellent resistance to sulfidizing
environments and other reducing gases.
3. Chemical Composition (Typical % Weight)
The following table outlines the standard chemical composition of
Hastelloy X as per ASTM/ASME and other common specifications.
Table 1: Standard Chemical Composition of Hastelloy X (UNS N06002)
| Element | ASTM B572 / ASME SB-572 | Werkstoff 2.4665 | Typical Average |
|---|
| Nickel (Ni) | Balance | Balance | Balance |
| Chromium (Cr) | 20.5 - 23.0 | 20.0 - 23.0 | 22.0 |
| Iron (Fe) | 17.0 - 20.0 | 17.0 - 20.0 | 18.5 |
| Molybdenum (Mo) | 8.0 - 10.0 | 8.0 - 10.0 | 9.0 |
| Cobalt (Co) | 0.5 - 2.5 | 0.5 - 2.5 | 1.5 |
| Tungsten (W) | 0.2 - 1.0 | 0.2 - 1.0 | 0.6 |
| Carbon (C) | 0.05 - 0.15 | 0.05 - 0.15 | 0.10 |
| Manganese (Mn) | 1.00 max | 1.00 max | 0.50 |
| Silicon (Si) | 1.00 max | 1.00 max | 0.50 |
| Phosphorus (P) | 0.040 max | 0.030 max | 0.015 |
| Sulfur (S) | 0.030 max | 0.015 max | 0.005 |
| Boron (B) | 0.010 max | 0.010 max | 0.005 |
Note: "Balance" for Nickel is typically around 47%.
4. Mechanical Properties
The mechanical properties of Hastelloy X are exceptional,
particularly at elevated temperatures. The following tables provide
typical room temperature and high-temperature properties for
hot-rolled and forged bars in the solution-annealed condition.
Table 2: Typical Room Temperature Mechanical Properties (Solution
Annealed)
| Property | Hot Rolled Bar (Diameter <100mm) | Forged Bar (Diameter 100-350mm) | Test Standard |
|---|
| Tensile Strength | 725 MPa (105 ksi) min | 690 MPa (100 ksi) min | ASTM E8 |
| Yield Strength (0.2% Offset) | 315 MPa (46 ksi) min | 310 MPa (45 ksi) min | ASTM E8 |
| Elongation (in 50mm) | 35% min | 30% min | ASTM E8 |
| Reduction of Area | 50% min | 45% min | ASTM E8 |
| Hardness (Brinell) | 180 - 240 HBW | 170 - 230 HBW | ASTM E10 |
Table 3: Typical Short-Time Elevated Temperature Properties
| Temperature | Tensile Strength | Yield Strength (0.2% Offset) | Elongation |
|---|
| 815°C (1500°F) | 380 MPa (55 ksi) | 195 MPa (28 ksi) | 40% |
| 980°C (1800°F) | 165 MPa (24 ksi) | 110 MPa (16 ksi) | 55% |
| 1095°C (2000°F) | 83 MPa (12 ksi) | 62 MPa (9 ksi) | 60% |
5. Product Specifications and Available Forms
Our Hastelloy X round bars are supplied in the solution-annealed
condition to ensure optimal corrosion resistance and mechanical
properties. They are available in a wide range of diameters to suit
various manufacturing needs.
Table 4: Hastelloy X Round Bar Product Specifications
| Parameter | Specification |
|---|
| Material | Hastelloy X (UNS N06002, 2.4665) |
| Product Form | Round Bar / Rod |
| Manufacturing Process | Hot Rolling (5mm - 100mm), Forging (80mm - 350mm) |
| Diameter Range | 5 mm to 350 mm |
| Standard Length | 3000mm to 6000mm (or cut-to-length as required) |
| Condition | Solution Annealed & Pickled/Descaled |
| Surface Finish | Black, Descaled, Machined (Turned/Peeled), or Centerless Ground |
| Applicable Standards | ASTM B572, ASME SB-572, AMS 5754, DIN 17752, DIN 17754 |
6. Manufacturing Process: Hot Rolling vs. Forging
Hot-Rolled Bars (5mm - 100mm): This process involves heating the
alloy billets above its recrystallization temperature and passing
them through a series of rollers to achieve the desired diameter.
Hot rolling is a cost-effective and efficient method for producing
smaller diameter bars with a fine, uniform grain structure. It is
ideal for applications where the bar will be subsequently machined
into components like bolts, fasteners, and shafts.
Forged Bars (80mm - 350mm): For larger diameters, we employ
open-die or closed-die forging. Forging involves applying
compressive forces to the heated billet, which results in a
superior, directional grain flow that follows the contour of the
bar. This process enhances the mechanical properties, particularly
toughness, fatigue resistance, and creep strength in the
longitudinal direction. Forged bars are preferred for the most
critical applications, such as turbine shafts, large valves, and
components subject to high cyclic stresses.
7. Applications
Hastelloy X round bars are specified across a wide range of
high-temperature industries due to their reliability. Key
application areas include:
Aerospace & Gas Turbines: Combustion cans, transition ducts, burner
liners, afterburner parts, turbine shafts, and spray bars.
Industrial Furnaces: Radiant tubes, muffles, retorts, furnace
rollers, and heat treatment baskets.
Power Generation: Heat exchangers, combustor components, and hot
gas path parts in land-based gas turbines.
Chemical Processing: Components for high-temperature catalytic
systems, pyrolysis reactors, and furnace hardware.
Pollution Control: Thermal oxidizer internals and flare tips.
8. Machining and Welding
Machining: Hastelloy X is machinable using methods similar to those
for austenitic stainless steels but requires more power due to its
high work-hardening rate. Positive rake angles, rigid setups, sharp
carbide tools, and constant feed rates are recommended. Use
heavy-duty cutting fluids for cooling and lubrication.
Welding: The alloy is readily weldable using common techniques like
Gas Tungsten Arc Welding (GTAW/TIG) and Gas Metal Arc Welding
(GMAW/MIG). Matching filler metals such as ERNiCrMo-2 or ENiCrMo-2
are typically used. Post-weld heat treatment is not usually
required for stress-relief but may be performed for optimal
properties in specific applications.
9. Conclusion
Our supply of Hastelloy X round bars, produced via controlled
hot-rolling and forging processes, guarantees a product with
consistent chemistry, superior mechanical integrity, and proven
performance in the world's most challenging high-temperature
environments. With a diameter range from 5mm to 350mm, we provide a
reliable solution for everything from precision-machined fasteners
to massive, high-stress forged shafts.
