Technical knowledge
ASTM B564 explained: what the flange material specification actually covers
What ASTM B564 covers, which UNS numbers it includes, how it relates to ASME B16.5 and B16.47, and the supplementary requirements you should state when ordering nickel alloy flanges.

Scope: material, not dimensions
The most common purchasing error is treating ASTM B564 as a complete flange specification. It is not. B564 tells you what the metal must be; ASME B16.5 tells you what shape it must be; ASME B16.20 covers the gasket; MSS SP-25 covers the marking. A flange can comply with all of these and still be wrong for the service if the heat treatment condition, NDT scope or hardness limit was never stated.
Common UNS numbers covered
| UNS number | Common name | Typical duty |
|---|---|---|
| N06625 | Inconel 625 | Seawater, sour, FGD, offshore |
| N08825 | Incoloy 825 | Sulphuric and phosphoric acid |
| N10276 | Hastelloy C-276 | Mixed and reducing acids |
| N06022 | Hastelloy C-22 | Oxidising contaminated acids |
| N04400 | Monel 400 | Seawater, hydrofluoric acid |
| N05500 | Monel K-500 | High strength marine |
| N06600 | Inconel 600 | Caustic, elevated temperature |
| N07718 | Inconel 718 | High strength and bolting |
| N02200 / N02201 | Nickel 200 / 201 | Caustic service |
Supplementary requirements worth stating
- Heat treatment condition. Solution annealed, annealed, or aged. This is the single most consequential line on the order.
- Hardness limit. Required for sour service and for ring type joint grooves.
- Non destructive examination. Ultrasonic testing of the forging, dye penetrant on machined surfaces.
- Grain size or impact testing. Needed for elevated temperature grades and for low temperature service.
- Corrosion testing. Intergranular or pitting tests where the service justifies it.
- Positive material identification. Specify the coverage percentage.
Documentation and traceability
Require a mill test certificate to EN 10204 3.1 quoting actual results for the heat lot, with the heat number shown on the certificate and marked on the flange to MSS SP-25. Where the owner, EPC or regulator requires independent verification, arrange inspection, sampling and laboratory testing by SGS and issue the resulting third party test report with the shipment.
Questions about this topic
Is ASTM B564 the same as ASME SB-564?
Does B564 cover the flange dimensions?
Can I order B564 flanges without stating heat treatment?
Questions about our products
What products does Hangbo Alloy supply?
Which alloy grades are available for these products?
What sizes, wall thicknesses and pressure classes can you supply?
Which material and dimensional standards do you work to?
Is there a minimum order quantity?
What inspection and certification is issued with the goods?
What are typical lead times?
How are the products packed for export?
How do I request a quotation or a sample?
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