API Coupling and Threads for Casing and Tubing

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API Coupling and Threads for Casing and Tubing

API Coupling refers to the steel couplings that used in connecting casing pipe and tubing. Also known by OCTG coupling, it is usually manufactured in seamless type, material grade same with the pipe body, same PSL or providing higher grades than requested. Same heat treatment also applicable, except there is an special requirements.As we know steel pipe coupling is a short pipe or tube that with threads on both ends,Iron Products Supplier used to connect pipelines. So It is a kind of pipe fittings that with threaded connection, the advantage is easy for pipeline maintenance or to replace the broken pipe.

With this purpose, API 5CT standard coupling plays an important feature in connecting casing and tubing line pipes. On the contrary, the biggest different with general steel pipe coupling is: API coupling manufacturing processes is more rigorous, requires a precisely control in the different processes as blew listed.As we told, one of the important figure of API coupling, that it shall be made of seamless, another is the same grade as the casing or tubing pipe body, and these materials are used for manufacturing the blank coupling.

Coupling should be processed from coupling blanks or from coupling stock, including manufactured in hot forging. (Except Grade C110 and Q125 couplings shall not be in hot forging. These two grades material are typically different from other grades, so if you are purchasing couplings in this grades, should pay more attention to read regulations in API 5CT spec.)In case specified in the contract, special-clearance (reduced outside diameter Wc) couplings for buttress (BTC connection) casing and external upset (EUE connection) tubing shall be furnished. Unless otherwise specified, special-clearance external upset tubing couplings shall have a special bevel on both ends. The inside and outside edges of the bearing face shall be rounded or beveled. The ends (or root face when beveled) of couplings shall be faced at right angles to the axis.

Combination couplings with different types of thread of the same specified size shall be furnished when specified on the contract. The minimum length and minimum OD of this coupling shall be sufficient to work with the specified size specified threads.Sealing-ring couplings conforming to the requirements shall be furnished when specified in the PO. Grooves may be cut before or after threading at manufacture's option. Grooves and threads shall be free of fins, wickers and ribbons that are loose or can become loose and fold into the thread dorm. Couplings shall be inspected after final machining of the groove.