A Complete Guide on Hastelloy C22 Seamless Pipe

Here is a comprehensive guide on Hastelloy C22 seamless pipes, covering their properties, manufacturing process, applications, and handling considerations.

Hastelloy C22 Seamless Pipe: A Complete Guide

The nickel-chromium-molybdenum-tungsten alloy Hastelloy C22 is renowned for its exceptional strength and resistance to corrosion. In industries where protection against extremely corrosive conditions is necessary, it is commonly employed. Hastelloy C22 seamless pipes are especially prized for their durability and dependability.

Chemical Composition

Hastelloy C22 has a unique chemical composition that contributes to its exceptional properties:

• Nickel (Ni): ~56%
• Chromium (Cr): 20–22.5%
• Molybdenum (Mo): 12.5–14.5%
• Tungsten (W): 2.5–3.5%
• Iron (Fe): 2–6%
• Cobalt (Co): 2.5% max
• Others: Carbon (C), Manganese (Mn), Silicon (Si), Vanadium (V), Phosphorus (P), Sulfur (S)

Key Properties

1. Corrosion Resistance:

• Resistant to pitting, crevice corrosion, and stress corrosion cracking.
• Performs well in oxidizing, reducing, and mixed environments.

1. Thermal Stability:

• Maintains mechanical integrity at high temperatures.
• Suitable for both high-temperature and cryogenic applications.

1. Mechanical Properties:

• High tensile strength and ductility.
• Excellent formability and weldability.

1. Non-Magnetic:

• Maintains non-magnetic properties across a range of temperatures and conditions.

Manufacturing Process

The production of Hastelloy C22 seamless pipes involves several key steps to ensure the highest quality:

1. Raw Material Selection:

• High-purity alloys are selected to meet stringent chemical composition standards.

1. Melting and Casting:

• The alloy is melted and cast into billets using techniques like vacuum induction melting to minimize impurities.

1. Extrusion or Rotary Piercing:

• Billets are hot-worked through extrusion or rotary piercing to form seamless pipes.

1. Cold Working:

• Pipes are cold-worked to refine the grain structure, enhancing strength and surface finish.

1. Heat Treatment:

• Annealing is performed to relieve stresses and enhance corrosion resistance.

1. Finishing and Inspection:

• Pipes undergo finishing processes such as polishing and are inspected for dimensional accuracy and defects.

Applications

Hastelloy C22 seamless pipes are used in a variety of industries and applications, including:

1. Chemical Processing:

• Ideal for reactors, heat exchangers, and piping handling corrosive chemicals.

1. Pharmaceuticals:

• Used in manufacturing equipment and piping where purity and corrosion resistance are critical.

1. Oil and Gas:

• Suitable for sour gas environments and downhole applications.

1. Environmental and Waste Treatment:

• Employed in pollution control and waste treatment equipment.

1. Marine and Aerospace:

• Used in components exposed to seawater and harsh environments.

Standards and Specifications

Hastelloy C22 seamless pipes are manufactured to meet various international standards, ensuring quality and consistency:

• ASTM B622: Standard Specification for Seamless Pipe and Tube.
• ASTM B619: Standard Specification for Welded Nickel and Nickel-Cobalt Alloy Pipe.

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