Oil casing coupling is the necessary work piece to connect two tubing casings. The manufacturing method is the same as the seamless pipe, 7 'casing coupling BTC, and domestically made of special steel such as J55 N80. Both ends of the steel pipe have internal threads to connect with the upper and lower oil pipes. In order to ensure the tightness of the joint, there are strict requirements on the accuracy of the thread.
Domestic oil casing is divided into non-thickened oil casing couplings and thickened oil casing couplings at both ends.
Car end face-car outer circle-boring-car internal thread-inspection-phosphating
Specification: 1.315 ''-4-1 / 2''Thread type: EUE / UPTBG , NUE / TBG.
Specification: 4-1 / 2``-20 ''. Thread type: SC , LTC , BTC