Description
Hastelloy C22 / Alloy C22 Flanges – ASTM B564 UNS N06022
Forged Alloy C22 flange solutions for demanding mixed, oxidizing and reducing chemical environments after project-specific corrosion review.
Quick engineering answer
Hastelloy C22 and Alloy C22 refer to UNS N06022, a nickel-chromium-molybdenum alloy with tungsten. ASTM B564 is the forged-product specification used for applicable C22 flanges; UNS N06022 is the correct UNS designation.
Product specification
| Material | ASTM B564 UNS N06022 nickel-chromium-molybdenum alloy |
|---|---|
| Available forms | Weld neck, blind, slip-on, socket weld, threaded, lap joint, orifice and drawing-specific flanges where permitted |
| Dimensional standards | ASME B16.5; ASME B16.47 for applicable large diameters; EN 1092-1 or approved drawings on request |
| Pressure classes | Class 150, 300, 400, 600, 900, 1500 and 2500 within the selected standard, material group and size limits |
| Facing | Raised Face (RF), Ring Type Joint (RTJ), Flat Face (FF) where permitted, or drawing-specific facing |
| Documentation | EN 10204 3.1 MTC, heat-number traceability, dimensional report and ordered inspection records |
Pressure-temperature ratings depend on the governing code, flange standard edition, material group, size and class. Confirm the complete project specification before ordering.
Grade and terminology check
| Correct UNS designation | N06022 | Use on purchase orders and MTCs |
|---|---|---|
| Forged product standard | ASTM B564 | Dimensional requirements are specified separately |
| Material comparison | C22 and C276 are distinct grades | No automatic substitution |
Material selection
Alloy C22 offers broad corrosion resistance in many severe chemical-process environments, but no alloy is universally immune. Temperature, concentration, contaminants, crevices, fabrication and actual process conditions must be reviewed using relevant corrosion data.
Matching-material note: C22 and C276 are different alloys and should not be interchanged by name. Match adjoining products to their correct product-form standard and obtain written engineering approval for any proposed substitution.
Quality controls available
- PMI and controlled material segregation
- Heat number and EN 10204 3.1 traceability
- Corrosion testing, UT or PT when ordered
- Dimensional, facing and marking inspection
Typical applications
Applications are selection cues, not blanket approvals. Process media, pressure, temperature, corrosion data, fatigue, fabrication and code requirements govern final suitability.
Standards hierarchy
Information required for quotation
Provide the material grade, flange type, standard and edition, NPS or DN, pressure class or PN rating, pipe schedule or exact bore, facing and finish, quantity, delivery destination, heat treatment, NDE, testing, certification and third-party inspection requirements.
Frequently asked questions
What is the correct UNS number for Hastelloy C22?
The correct designation is UNS N06022. Purchase documents should also state ASTM B564 for forged flanges.
Are Alloy C22 and Hastelloy C22 the same?
Alloy C22 is the generic grade name and Hastelloy C22 is a recognized trade name associated with UNS N06022. The UNS number and product standard provide the clearest procurement identity.
Can C22 replace C276?
Not without engineering review. They have different chemistry and may behave differently in the actual service environment, fabrication route and project design.
Request a specification review and quotation
Send the complete RFQ or piping material specification. SASA FLANGE will review grade identity, dimensions, facing, inspection and documentation before production.
Related products and engineering resources
Nickel Alloy Material Center Hastelloy C276 Flanges All Flanges
