Overview
ASTM A240/A240M is the principal ASTM product specification for chromium, chromium-nickel and chromium-manganese-nickel stainless steel plate, sheet and strip used in pressure-vessel and general applications. A valid order still needs the exact grade, product form, dimensions, finish, condition and referenced A480 requirements.
Designation and acceptance
ASTM A240/A240M-26 identifies the stainless flat-product specification, while ASTM A480/A480M supplies general requirements for flat-rolled stainless and heat-resisting steel. A240 does not make plate, sheet and strip interchangeable labels: product form affects dimensional tolerances, surface expectations, testing and downstream fabrication. The order must also select the A or A/M unit system consistently.
Members and selection
| Designation | Selection context |
|---|---|
| Plate | Use the plate product description with exact thickness, width, length, edge condition, flatness and any pressure-vessel additions. |
| Sheet | Define sheet gauge or thickness, width, length, finish, flatness and protective-film needs for formed or architectural components. |
| Strip | Specify narrow-width strip, slit-edge condition, coil geometry and tolerance controls needed for stamping or continuous fabrication. |
| A240 + A480 | Read the product specification with the referenced general requirements; resolve any purchase-order additions without waiving mandatory acceptance. |
Comparison framework
| Criterion | Decision context |
|---|---|
| Product identity | Plate, sheet and strip share a material document but retain different dimensional and commercial form requirements. |
| Grade identity | A grade or UNS number selects composition and properties within scope; it does not state finish, dimensions or product form. |
| Finish and surface | Surface finish and protective handling are purchase decisions and should not be inferred from the word stainless. |
| Unit system | A240 and A240M values are separate systems; the order should not combine them as if every value were an exact conversion. |
Performance
- Corrosion performance depends on the exact grade, surface condition, fabrication contamination, environment and maintenance rather than the A240 label alone.
- Strength and ductility vary with grade, thickness and delivered condition, so design values must come from the governing product and project documents.
- Flatness, surface quality and edge condition can determine fabrication yield even when chemistry and tensile tests conform.
Orderable product scope
- Pressure-vessel plate requires the applicable design-code review, grade, thickness, condition and project-specific inspection beyond basic material conformity.
- General sheet for enclosures, food equipment or architectural work requires finish, directional grain, film and fabrication controls.
- Strip and slit coil require width, ID/OD or mass, edge, camber, telescoping and packaging details appropriate to the processing line.
Processing
- Confirm whether hot rolling, cold rolling, solution treatment, pickling or final polishing defines the delivered condition and surface.
- Protect stainless surfaces from carbon-steel contamination during slitting, handling, forming, welding and storage.
- Qualify forming and welding from actual grade, thickness and condition; post-fabrication cleaning or passivation remains a separate requirement.
Applications
- Plate for tanks, vessels and fabricated equipment where the governing construction code separately approves the material.
- Sheet for food-service equipment, enclosures, cladding, ductwork and formed components with controlled appearance.
- Strip for stamped parts, springs, clamps, heat-exchanger components and continuous roll-forming operations.
Selection
- Choose the stainless grade from corrosion, temperature, fabrication and mechanical requirements before selecting the flat-product form.
- Match plate, sheet or strip dimensions and tolerance needs to A480 and the actual manufacturing route.
- Add finish, condition, tests, inspection document, packaging and code/project controls to make the RFQ orderable.
Procurement
- State ASTM A240/A240M-26 or the contract-required edition and use one unit system consistently.
- State grade/UNS, plate sheet or strip, thickness, width, length or coil requirements and quantity.
- Define finish, edge, flatness, surface acceptance, protective film, condition and fabrication-sensitive restrictions.
- Specify supplementary requirements, tests, inspection certificate, marking, heat traceability and packaging.