Article
ASTM A240 covers chromium and chromium-nickel stainless steel plate, sheet and strip for pressure vessels and general applications. It is the standard behind the stainless steel used for tanks, vessels, heat exchangers, fabricated fittings and structural work.
Plate, sheet and coil
The terms describe thickness and form, and usage varies slightly by region. Broadly, sheet is thin material (under about 6 mm), plate is thicker, and coil is sheet or strip supplied wound, to be cut to length or slit by the user. Plate is usually hot rolled; thin sheet is cold rolled.
Common grades
- 304 / 304L: the general-purpose austenitic grade.
- 316 / 316L: with molybdenum, for chloride environments.
- 321 and 347: stabilised grades for elevated temperature.
- 310S: heat-resistant, for furnace parts.
- 2205: duplex, for strength and chloride resistance.
- 430 and 409: ferritic grades for non-pressure use.
Surface finishes
| Finish | How it is made | Appearance and use |
|---|---|---|
| No.1 | Hot rolled, annealed and pickled | Dull, rough. Plate for industrial and pressure use where appearance does not matter. |
| 2D | Cold rolled, annealed and pickled | Dull, uniform. Deep drawing. |
| 2B | Cold rolled, annealed, pickled and lightly skin-passed | Smooth, slightly reflective. The most common sheet finish. |
| BA | Cold rolled and bright annealed in a controlled atmosphere | Mirror-like. Decorative, reflectors, some hygienic uses. |
| No.4 | Polished with abrasive | Brushed, directional grain. Kitchen equipment, architectural panels. |
A finish is a surface specification, not a grade. The same 316L can be supplied in No.1, 2B or No.4.
Tolerances
Thickness, width, length and flatness tolerances for A240 material are given in ASTM A480, the general requirements standard. For a job where flatness matters, such as a flange or a tube sheet cut from plate, say so on the order.
What to put on the enquiry
The grade (and whether dual certification such as 316/316L is acceptable), the thickness, width and length or the cut sizes, the finish, the quantity, and whether protective film is required on the surface.
See SS 316 plate to ASTM A240 and the sheets, plates and coils range.
Frequently asked questions
What does ASTM A240 cover?
Chromium and chromium-nickel stainless steel plate, sheet and strip for pressure vessels and general applications.
What is the difference between No. 1 and 2B finish?
No. 1 is hot rolled, annealed and pickled (dull, rougher); 2B is cold rolled, annealed, pickled and skin passed (smooth, slightly reflective).
Is 316L plate dual certified?
Plate is commonly supplied dual certified as 316/316L, meeting the requirements of both grades.
Key takeaways
- A240 is the main stainless plate and sheet specification.
- Finish (No. 1, 2B, BA, No. 4) must be stated in the order.
- Ask for protective film if surface appearance matters.
Need these products?
Sawariya Metal Industries supplies stainless steel pipes, flanges and buttweld pipe fittings from Mumbai to buyers in India and overseas. Send your size, grade, standard and quantity through our enquiry form and we will reply with a clear quotation and the test documents you need. You can also browse our stainless steel pipes, flanges and buttweld fittings.