ASTM Standard Hastelloy X Round Bar Custom Sizes Available for
Petrochemical Use
Product Overview
Hastelloy X is a nickel-chromium-iron-molybdenum alloy specifically
designed for high-temperature service in severely corrosive
environments. This solid-solution strengthened superalloy delivers
exceptional oxidation resistance at temperatures up to 1200°C
(2200°F) and maintains good strength at elevated temperatures.
Round bars manufactured from Hastelloy X are particularly valued in
the petrochemical industry for their reliability in critical
applications such as furnace components, reformer tubes, and
reactor parts where both high temperature strength and corrosion
resistance are required.
Chemical Composition
The chemical composition of Hastelloy X is carefully balanced to
provide its signature high-temperature properties. The table below
details the elemental composition range.
Table 1: Chemical Composition of Hastelloy X (Weight %)
| Element | Content (%) | Element | Content (%) |
|---|
| Nickel (Ni) | Balance | Tungsten (W) | 0.2 - 1.0 |
| Chromium (Cr) | 20.5 - 23.5 | Carbon (C) | 0.05 - 0.15 |
| Iron (Fe) | 17.0 - 20.0 | Manganese (Mn) | ≤ 1.0 |
| Molybdenum (Mo) | 8.0 - 10.0 | Silicon (Si) | ≤ 1.0 |
| Cobalt (Co) | 0.5 - 2.5 | Sulfur (S) | ≤ 0.010 |
| Aluminum (Al) | ≤ 0.50 | Phosphorus (P) | ≤ 0.015 |
Nickel (Base) provides the fundamental matrix, offering inherent
ductility, toughness, and resistance to various corrosive media.
Chromium is the primary element responsible for the alloy's
exceptional oxidation resistance at high temperatures by forming a
protective chromium oxide scale.
Molybdenum and Tungsten contribute to solid-solution strengthening,
enhancing high-temperature strength and creep resistance.
Iron content helps to optimize cost and certain performance
characteristics.
Mechanical Properties
Hastelloy X round bars exhibit a robust combination of strength and
ductility at both room and elevated temperatures. The following
table outlines the typical minimum mechanical properties at room
temperature for solution-annealed material.
*Table 2: Typical Mechanical Properties of Hastelloy X Round Bar
(Solution-Annealed Condition)*
| Property | Value |
|---|
| Density | 8.3 g/cm³ (0.30 lb/in³) |
| Melting Point Range | 1260°C - 1355°C (2300°F - 2470°F) |
| Tensile Strength | ≥ 665 MPa (96 ksi) |
| Yield Strength (0.2% Offset) | ≥ 240 MPa (35 ksi) |
| Elongation (A5) | ≥ 35% |
| Hardness (Brinell) | ≥ 241 HBS |
These properties ensure that Hastelloy X round bars can withstand
significant structural loads while providing good fatigue
resistance and fracture toughness in demanding service conditions.
Key Characteristics & Advantages
Hastelloy X is distinguished by several key characteristics that
make it a preferred material for high-temperature petrochemical
applications.
Exceptional High-Temperature Strength: The alloy retains a
significant portion of its strength at elevated temperatures,
exhibiting excellent creep and stress-rupture properties above
790°C (1450°F) . This makes it ideal for components under sustained
mechanical loads at high temperatures.
Superior Oxidation Resistance: With a chromium content of over 20%,
Hastelloy X possesses outstanding oxidation resistance up to 1200°C
. It performs reliably in both oxidizing and reducing atmospheres,
preventing rapid degradation.
Excellent Resistance to Corrosive Environments: The
nickel-chromium-molybdenum base provides strong resistance to a
variety of corrosive attacks, including sulfidation, carburization,
and halogen-containing atmospheres . This is crucial in
petrochemical processes where such environments are common.
Good Fabricability: Hastelloy X offers good formability and
weldability . It can be welded using common techniques such as TIG
(Tungsten Inert Gas) and MIG (Metal Inert Gas) welding without the
need for post-weld heat treatment, facilitating the fabrication of
complex components .
Stable Microstructure: In the solution-annealed condition, the
alloy's structure is an austenitic matrix with minimal secondary
phases, ensuring long-term stability and performance at high
temperatures .
Standards & Equivalent Grades
Hastelloy X round bars are produced to meet various international
standards, ensuring material quality and consistency. The primary
standard for round bars is ASTM B572 .
Table 3: Standard and Equivalent Grades for Hastelloy X
| Country/Region | Standard | Grade/UNS |
|---|
| USA | ASTM B572
UNS | UNS N06002 |
| Germany | DIN & Werkstoff Nr. | 2.4665 |
| China | GB/T | GH3536 / NS3102 |
| France | AFNOR | NC22FeD |
| UK | B.S. | Nimonic PE13 |
| Europe | ISO | NiCr21Fe18Mo9 |
Other relevant standards for Hastelloy X products include AMS 5754
for forgings and ASTM B622 for seamless pipes
Applications in Petrochemical and Other Industries
The unique combination of properties makes Hastelloy X round bars
suitable for a wide range of demanding applications.
Summary
Hastelloy X round bar is a premium, high-performance nickel-based
alloy engineered to solve the most challenging high-temperature and
corrosion problems in the petrochemical and other heavy industries.
Its balanced composition delivers an unmatched mix of extreme
oxidation resistance, high structural strength, and excellent
fabricability. Manufactured to strict standards like ASTM B572, it
provides a reliable material solution for custom-sized components
operating under severe conditions, ensuring long service life and
operational safety.
