What is a 240 or sa 240 304h 304l difference?

Difference Between A240 and SA 240 for 304H and 304L Stainless Steel

The query appears to ask about the difference between A240 (ASTM A240) and SA 240 (ASME SA 240) specifications, particularly for 304H and 304L grades. These are related but distinct standards for stainless steel plates, sheets, and strips. Below, I'll explain the differences, focusing on how they apply to 304H (high-carbon for high-temperature service) and 304L (low-carbon for weldability). Both standards cover the same materials, but SA 240 adds ASME certification for pressure vessel use.

A240 vs. SA 240: Key Differences

• A240 (ASTM A240/A240M): An ASTM International standard for chromium and chromium-nickel stainless steel plates/sheets for pressure vessels and general applications. It defines chemical composition, mechanical properties, and testing but is not tied to specific codes like BPVC. It's widely used for general fabrication.

• SA 240 (ASME SA-240/SA-240M): The ASME adoption of ASTM A240, incorporated into the BPVC. It has identical technical requirements but includes additional ASME-specific certification, testing (e.g., tensile, impact), and traceability for pressure vessel compliance (e.g., Section VIII). SA 240 is mandatory for ASME-coded vessels.

Summary of Differences:

• Content: Technically identical; SA 240 references A240 but adds BPVC alignment.
• Certification: A240 is general; SA 240 requires ASME certification for pressure vessels.
• Use: A240 for non-code applications; SA 240 for BPVC-compliant designs.
• Impact on 304H/304L: No material differences; SA 240 ensures higher traceability for high-temp (304H) or welded (304L) applications.

304H vs. 304L Under A240/SA 240: Key Differences

Both are austenitic stainless steels (density 8.00 g/cm³, non-magnetic in annealed state), but carbon content drives their distinctions:

• 304H: Higher carbon boosts creep resistance for elevated temperatures (e.g., power generation), but requires annealing to prevent weld corrosion.
• 304L: Lower carbon prioritizes weldability and intergranular corrosion resistance, ideal for fabricated parts.

Which Specification to Choose?

• A240: For general, non-code applications (e.g., fabrication, non-pressure vessels).
• SA 240: For BPVC-compliant pressure vessels, where certification is required.

For pricing, SA 240 GR 304H plates are ~$1.60/kg FOB (Gangsteel, MOQ 1 ton). Contact admin@gangsteel.com for quotes.