This specification identifies requirements for the foundry qualification, production, design, marking, and documentation of carbon steel, alloy steel, stainless steel, and nickel base alloy castings used in the petroleum and natural gas industries when referenced by an applicable API product standard or otherwise specified as a requirement for compliance.

This specification applies to castings used in the manufacture of pressure-containing, pressure-controlling and primary load-bearing components. Castings manufactured in accordance with this API specification may be produced using any industry standard casting method.

It also provides manufacturers with a fixed methodology to examine a qualification casting and to compare the results of that examination with a defined set of acceptance criteria. The results of the qualification testing by material grouping are then used to establish a baseline casting specification level (CSL) for subsequently produced castings.