NICKEL-CHROMIUM-MOLYBDENUM ALLOY

Hastelloy C22 Tube Sheet

Higher chromium than C276, giving improved resistance in certain oxidizing conditions (notably wet chlorine and ferric/cupric chloride) plus better as-welded corrosion resistance without post-weld heat treatment.

UNS N06022 ASTM B575 / B622 Higher Cr than C276

Chemical Composition

ElementMin %Max %
Nickel (Ni)Balance
Chromium (Cr)20.022.5
Molybdenum (Mo)12.514.5
Tungsten (W)2.53.5
Iron (Fe)2.06.0
Carbon (C)0.015

Mechanical Properties

PropertyTypical Value
Tensile Strength690 MPa min (annealed)
Yield Strength (0.2% offset)310 MPa min (annealed)
Elongation45% min
Max. Practical Service Temp.~550°C

Equivalent Grades

StandardDesignation
ASTM / UNSN06022
EN / DIN2.4602
Trade NameHastelloy® C-22 (Haynes International)

C22 vs. C276 — Which One

Attribute
C276
C22
Chromium Content
14.5-16.5%
20-22.5%
As-Welded Corrosion Resistance
Good
Better
Best For
Broad reducing/oxidizing mix
Wet chlorine, ferric/cupric chloride

See the full Hastelloy C276 datasheet for the broader-spectrum alternative.

Applications

Chlorine dioxide bleach plants, wet chlorine processing, ferric and cupric chloride etching solutions, and pharmaceutical processes with aggressive cleaning agents where welded fabrication without PWHT is required.

Advantages & Limitations

Advantages

  • Superior as-welded resistance vs. C276, no PWHT required
  • Better resistance to wet chlorine and oxidizing chloride solutions
  • Excellent resistance to pitting and crevice corrosion

Limitations

  • Similar high cost to C276
  • Slow, tool-intensive machining
  • C276 may be preferred for broader mixed-acid resistance

FAQ

Not exactly an upgrade — the two are optimized for slightly different conditions. C22's higher chromium gives it an edge in wet chlorine and certain oxidizing chloride solutions, while C276 has a longer track record across a broader range of reducing acid conditions.

No — C22's low carbon and high chromium content give it good as-welded corrosion resistance without requiring PWHT, which is one of its key practical advantages over some other corrosion-resistant alloys.

Similar to C276 — typically sourced to order given specialist demand. Send your specification and quantity for a confirmed schedule.

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