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 %)

• 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)*

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.

1. 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.

2. 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.

3. 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.

4. 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 .

5. 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

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.

• Petrochemical Industry:

  • Furnace components (e.g., radiant tubes, convection tubes, and pigtails)

  • Reformer and cracking tubes

  • High-temperature reactor parts

  • Components in environments with sulfur and other corrosive species 

• Aerospace and Gas Turbines:

  • Combustion chambers and liners

  • Afterburner components

  • Tailpipes

  • Turbine shrouds 

• Industrial Heating Technology:

  • Heat treatment fixtures (e.g., grid plates, furnace rolls)

  • Heat exchangers

  • Burner nozzles 

• Power Generation:

  • Components in gas turbines and nuclear reactors 

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.