API Connections

We manufacture a complete range of API-certified connections.

U. S. Steel Tubular Products manufactures a complete range of American Petroleum Institute (API) certified casing thread types, including short round thread casing (STC), long round thread casing (LTC) and buttress thread casing (BTC). STC and LTC both feature a non–runout design of round threads, each with eight round crested threads per inch. BTC has a square thread with a flat root and crest, a runout design, and five buttress threads per inch.


Each thread type is suited for a specific well condition. STC is a good choice for shorter length casing applications that do not involve high axial loads or bending. LTC is well suited for situations where some axial load is encountered but overall well conditions do not include extremes of temperature or pressure. BTC is an excellent connection for use in well situations involving higher axial loads and moderate internal pressures and temperatures.

U. S. Steel Tubular Products’ other API connections include non–upset end tubing (NUE) and external–upset end tubing (EUE). Both offer eight or ten round threads per inch and a non–runout design of round threads. NUE is well suited to light duty, general purpose applications.

EUE can be deployed for general purpose drilling and production applications where internal pressures are moderate.

U. S. Steel Oilwell Services Threading Services

U. S. Steel Oilwell Services specializes in complex threading of OCTG. We provide API and premium threading of OCTG , ranging in size from 3-1/2” to 20” outside diameter. Tubing and casing threading services encompass bucking, torque turn, saw cutting, and full-length drift.

We provide threading through U. S. Steel Oilwell Services – Offshore Operations, Houston and through Patriot Premium Threading Services in Midland, Texas.

U. S. Steel Tubular Products OCTG Distributors

U. S. Steel Tubular Products are available through authorized distributors. See our complete list of U. S. Steel Tubular Products OCTG product distributors and authorized agents.