ASTM A240

Covers — chromium and chromium-nickel stainless steel plate, sheet, and strip for pressure vessels and general applications, across austenitic (304/316/321/347), ferritic, martensitic, and duplex (2205, 2507) grades.

Does NOT cover (exclusions) — the following are governed elsewhere:

• Finished stainless pipe/tube → ASTM A312 / A358.
• Forged stainless components → ASTM A182; cast stainless → ASTM A351.
• Vessel design rules that use the plate → ASME BPVC Section VIII.

A240 is the flat product; it becomes welded pipe, vessel shells, and formed fittings downstream.

A240 sets minimum requirements for the flat product:

• Chemistry — grade-specific stainless composition (austenitic, ferritic, martensitic, duplex).
• Mechanical Properties — tensile/yield/elongation and hardness by grade and thickness.
• Heat Treatment — solution annealing (austenitic/duplex) with pickling as required.
• Testing — tension/hardness testing, and intergranular-corrosion or ferrite testing where specified.

ASTM A240 is the specification for stainless steel plate, sheet, and strip — the flat product from which welded stainless pipe, vessel shells, and fabricated fittings are made. It spans austenitic, ferritic, martensitic, and increasingly duplex grades.

When welded pipe is produced from A240 plate (e.g., A312 welded, A358), the plate's certified chemistry and properties carry into the finished pipe. Vessel design under ASME Section VIII draws its allowable stresses from these grades.

Engineering Note: For chloride-bearing or higher-strength duty, duplex grades (2205/2507) qualified to A240 offer better stress-corrosion and strength performance than 304/316 — check availability and welding qualification.