Alloy C22 - UNS N06022

Alloy C22, UNS N06022, is commonly associated with ASTM B574 - ASTM B575 - ASME SB564.
Alloy C22 is commonly known as Hastelloy® C-22. Alloy C22 is a Nickel-Chrome-Moly alloy.
Mechanical properties here.


Ni Cr Mn C Mo Si Fe
Max % Bal 22.5 0.50 0.015 14.5 0.08 6.0
Min % 20.0 12.5 2.0

Typical Inventory

Round Bar

Product Description

Alloy C22, also known as HASTELLOY C-22, is a nickel-chromium-molybdenum alloy with enhanced resistance to pitting, crevice corrosion, and stress corrosion cracking. This alloy is resistant to the formation of grain boundary precipitates, specifically in the weld-heat affected zone. This attribute makes alloy C-22 suitable for use in the as-welded condition. C-22 has outstanding resistance to both reducing and oxidizing media. Due to these corrosion resistant properties, alloy C22 can be used where challenging conditions are likely to occur. The alloy has been proven to possess excellent weldability and high corrosion resistance as consumable filler wires and electrodes. Alloy C-22 also has proven results as a filler wire in many applications.

C-22 can easily be cold-worked because of its ductility. Cold-forming is the preferred method of forming. Cold working requires more energy during production because the alloy is stiffer than austenitic stainless steels. For comparison, a 0.28" thick sheet in the heat-treated at 2050°F, rapid quenched condition, has an average olsen cup depth of 0.49".

General Data

Alloy C-22 is a great alternative when super austenitic stainless steels (AL-6XN®, 904L, and 254 SMO®) and duplex stainless steels (2205 and 2507) will not withstand extremely aggressive media. This is because it is a nickel-chromium-molybdenum-tungsten alloy with better overall resistance to uniform and localized corrosion than any other Ni-Cr-Mo alloys such as Hastelloy C-276, C-4, and alloy 625.

  • No crevice and pitting corrosion, no product accretion.
  • Highly corrosion resistant.
  • Can be cold-worked to enhance properties.


C-22 is used in severely corrosive media with high chloride and temperature applications such as buffer solutions, active pharmaceutical ingredients (API), fabric softeners, cleaning supplies, and fish, soy and chili sauce.

Mechanical Properties

The typical properties listed can usually be provided in rounds, sheet, strip, plate, & custom forgings. We have the equipment to produce small quantities in special sizes to meet our customers’ specific needs.

Minimum Properties Acceptable for Material Specification Annealed Bars
Ultimate Tensile ksi (MPa) Yield Strength ksi (MPa) Elong. % in 2 in.
100 (690) 45 (310) 35 45

Common Specifications

Please, note that the specs listed are for reference and are not comprehensive nor indicative of the actual specifications listed on the Material Test Report (MTR). If you have a special spec requirement, then please reach out to our sales department at 1-800-472-5569.

Form Standard
Metal Type UNS N06022
Bar ASTM B574
Sheet ASTM B575
Plate ASTM B575
Fitting ASME SB-366
Forging ASME SB-564
Weld Wire
Weld Electrode


Nickel and cobalt based alloys can be difficult to machinine. However, it should be emphasized that these alloys can be machined using conventional production methods at satisfactory rates. These alloys harden rapidly, generate high heat during cutting, weld to the cutting tool surface and offer high resistance to metal removal because of their high shear strengths. The following are key points which should be considered during machining operations:

  • CAPACITY - Machine should be rigid and overpowered as much as possible.
  • RIGIDITY - Work piece and tool should be held rigid. Minimize tool overhang.
  • TOOL SHARPNESS - Make sure tools are sharp at all times. Change to sharpened tools at regular intervals rather than out of necessity. A 0.015 inch wear land is considered a dull tool.
  • TOOLS - Use positive rake angle tools for most machining operations. Negative rake angle tools can be considered for intermittent cuts and heavy stock removal. Carbide-tipped tools are suggested for most applications. High speed tools can be used, with lower production rates, and are often recommended for intermittent cuts.
  • POSITIVE CUTS - Use heavy, constant, feeds to maintain positive cutting action. If feed slows and the tool dwells in the cut, work hardening occurs, tool life deteriorates and close tolerances are impossible.
  • LUBRICATION - lubricants are desirable. Soluble oils are recommended especially when using carbide tooling.

Ulbrich's information on alloy 22

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