ASTM A666 vs ASTM A240 at a Glance
| Item | ASTM A666 | ASTM A240/A240M |
|---|---|---|
| Material scope | Austenitic stainless steels | Chromium and chromium-nickel stainless steels covered by the specification |
| Product forms | Sheet, strip, plate and flat bar | Plate, sheet and strip |
| Condition emphasis | Annealed and normally required cold-worked conditions | Grade, heat treatment and mechanical requirements defined by the order and specification |
| Typical selection driver | Cold-worked austenitic flat products and temper requirements | General or pressure-related flat-product requirements, subject to the governing code |
When ASTM A666 Is the Better Starting Point
Use ASTM A666 as the starting specification when the order is for an austenitic stainless flat product and the required cold-worked condition or mechanical properties are central to the purchase. The order should still state the grade, thickness, width, condition, finish, edge and test-document requirements.
When ASTM A240/A240M Is the Better Starting Point
ASTM A240/A240M is commonly specified for stainless plate, sheet or strip used in general fabrication and in pressure-related applications. Specifying A240 does not by itself prove that a finished component is accepted for a pressure service. The applicable design code, grade, thickness, heat treatment, fabrication procedure and inspection requirements must also be confirmed.
Where ASTM A480/A480M Fits
ASTM A480/A480M supplies general requirements used with stainless flat-product specifications, including ordering information, dimensions, tolerances, workmanship and testing provisions. Buyers should not combine inch-pound and SI requirements in the same order unless the contract clearly defines the controlling unit system.
A Practical Selection Sequence
- Define the product form: plate, sheet, strip or flat bar.
- Confirm the alloy family and grade: do not assume every stainless grade appears in both standards.
- State the required condition: annealed, cold-worked temper or another specified condition.
- Identify the governing application code: especially for pressure equipment or regulated service.
- Add dimensional and finish requirements: thickness, width, tolerance, surface and edge.
- Specify documentation: inspection certificate, test scope, marking and traceability.
RFQ Checklist
- Standard and edition, grade and unit system
- Product form, thickness, width, length and quantity
- Annealed or cold-worked condition and required mechanical properties
- Surface finish, edge condition and protective-film requirement
- Applicable design code, supplementary tests and inspection documents
Common Questions
Can ASTM A666 and ASTM A240 be treated as interchangeable?
No. Their scopes and purchasing emphasis differ. Check the exact grade, form, condition and application requirements before substituting one specification for another.
Does ASTM A240 alone qualify material for a pressure vessel?
No. Material specification is only one part of acceptance. The governing design code and project requirements control final suitability.
For related product options, see our stainless steel sheet and plate. You may also review our stainless steel sheet surface guide and edge-condition guide.
Post time: Nov-05-2026