API series casing and tubing are steel pipes conforming to API SPEC 5CT issued by the American Petroleum Institute, mainly used for oil and gas exploitation. Tubing extracts oil or gas from wells, and casing supports wellbores of oil & gas wells.

Applicable Standards & Technical Requirements
API SPEC 5CT Specification for Casing and Tubing
ISO 11960 Petroleum and natural gas industries — Steel pipes for use as casing or tubing for wells
GB/T 19830 Petroleum and natural gas industries — Steel pipes for use as casing or tubing for wells

Mechanical Properties