Internationally recognized specifications ASTM A263, ASTM A264 and ASTM A265 were introduced in 1943 by the World Trade Organization Technical Barriers to Trade Committee. While these specifications are very similar, the differences can be seen in the metal combinations for explosion welded clad plate.

The World Trade Organization Technical Barriers to Trade Committee created these specifications to standardize definitions, markings, procedures, repairs etc so purchasing departments can invoke requirements when placing clad orders from vendors.

ASTM A263 is for stainless chromium steel clad plate. The specification verifies plate of carbon steel or low-alloy steel metallurgically bonded to a thin layer of stainless chromium steel on one or two sides.

ASTM A264 is for stainless chromium-nickel-clad plate. The specification verifies plate of carbon steel or low-alloy steel metallurgically bonded to a layer of stainless chromium-nickel steel on one or two sides.

ASTM A265 is for nickel and nickel-base alloy-clad steel plate. The specification verifies plate of carbon steel or low-alloy steel metallurgically bonded to a layer of nickel or nickel-base alloy on one or two sides.

All three specifications can be used in combination with any cladding operation that produces plate for project design and processing requirements, including explosion bonding, roll bonding, and weld overlay. With a solid-state bond, fabricators, owner-operators, and clad manufacturers trust ASTM A263, ASTM A264 and ASTM A265-certified clad plates for pressure vessels and other uses where the above metal combinations require quality control of the clad in chemical & petrochemical, oil & gas, power generation, and metals extraction & refining operations. The functional benefits of using certified clad plates are many—from design flexibility to equipment reliability, which lowers operational and maintenance costs.

Source: https://www.astm.org/