C22

Alloy C22

UNS N06022 / W.Nr. 2.4602

COMMON TRADE NAMES: Hastelloy® C22

Alloy C22 is a nickel-chromium-molybdenum solid solution strengthened super-alloy with a nominal chemical composition of 56% nickel, 22% chromium, and 13% molybdenum, with additions of iron, tungsten, and cobalt. It is commonly referred to by the tradename Hastelloy® C22 and the universal designation UNS N06022. C22 has excellent corrosion and oxidation resistance, great mechanical properties over a wide range of temperatures, and good fabrication properties.

Characteristics

Corrosion Resistance

Alloy C22 is one of the most corrosion-resistant alloys available, even outperforming C276 and 625. It is resistant to almost all reducing and oxidizing environments, including strong oxidizers, seawater, and organic acids. In addition, C22 has excellent resistance to chloride-induced localized corrosion, including pitting, crevice corrosion, and stress corrosion cracking.
Oxidation Resistance

Oxidation Resistance

C22 has excellent resistance to oxidation, carburization, and sulfidation at elevated temperatures. However, C22 should not be used at temperatures above 1250°F due to the possible formation of embrittling phases.
Mechanical Properties

Mechanical Properties

C22 is typically provided in the annealed condition with a minimum yield strength of 45 ksi. However, C22 can be cold worked to higher strength levels.

Heat Treatment

C22 is typically annealed at 2050°F (1121°C), followed by rapid cooling.
Workability

Workability

C22 can be hot worked or cold worked. However, C22 work-hardens rapidly. Therefore, cold working must often be performed in stages with intervening anneals. Parts should be annealed after cold working.

Applications

The exceptional corrosion resistance of C22 has promoted its use in many different markets wherever harsh environments are encountered, including the chemical process, pharmaceutical, food processing, oil & gas, power generation, and the paper industries. CRA offers specialty alloy C22 seamless pipe & tube for use in multiple industries and applications, including:

  • Chemical Processing
  • Food Processing
  • Pharmaceutical Industry
  • Oil & Gas
  • Power Generation
  • Pulp & Paper Industries

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Chemical Composition

CCrNiFeMnSiMoCoPSVW
≤ 0.01520 - 22.5BAL2 - 6≤ 0.5≤ 0.0812.5 - 14.5≤ 2.5≤ 0.02≤ 0.02≤ 0.352.5 - 3.5
(mass %)

Specifications

ASTM B622, ASME SB622

Specified Mechanical Properties in Annealed Condition

Per ASTM B622, ASME SB622
Tensile StrengthYield StrengthElongation
minimum, ksiminimum, ksiminimum, %
1004545

Typical Physical & Mechanical Properties in Annealed Condition

  70°F200°F400°F600°F800°F1000°F
Densitylbs/in30.314-----
Thermal ExpansionX10-6/°F-6.96.977.47.7
Elastic Modulus102 ksi29.929.428.527.626.625.7
Poisson Ratio-0.3-----
Thermal ConductivityBtu-in/h·ft2·°F697694110125139
Specific HeatBtu/lb·°F0.0980.1010.1060.1110.1140.118
Yield Strengthksi544941363534
Tensile Strengthksi11410798959288

Manufacturing Process

PROCESSDESCRIPTION
Steel MakingElectric Arc Furnace followed by Vacuum Oxygen Decarburization (VOD) or Argon Oxygen Decarburization (AOD).
Pipe MakingConventional Seamless Cold Finished Pipe and Tube Manufacturing Processes.
Heat TreatmentCannot be hardened by heat treatment. Typically provided in the annealed condition.

Related Alloys

C22 is part of the Hastelloy® C family of Ni-Cr-Mo alloys. C276 is the ancestor of C22 and is a versatile alloy with resistance to many corrosive environments.

Product Availability

CRA offers this alloy in:
Seamless Pipe & Tube

MIN OD: 2-1/16″ (2.0625″)
MAX OD: 10-3/4″ (10.750”)
THICKNESS: Up to 1.925”
LENGTHS: Up to 70′

Standard & Non-Standard Sizes Available.

Manufactured Material Available as Quickly as 1 Week.

Non-Standard Mill Quantities Accommodated