API Oil Casing Thread Connection

API oil casing threaded connection usually consists of two parts: pipe or external thread end and coupling or internal thread end. Those with external threads are called pipes or male ends, and those with internal threads are called pipe joints or female ends. Today, we will briefly introduce the threaded connection of API oil casing.

API specifications include 4 types of threads, namely line pipe threads, round threads, trapezoidal threads and direct connection threads. Line pipes, round threads, and trapezoidal threads all need to fit together when tightening and assembling to prevent leakage of sealing grease at the threads. The threaded end of the direct coupling sleeve is designed to be sealed, and the sealing of the direct coupling is achieved by a metal-to-metal seal.

Main Parameters of API Standard Thread:

(1) Thread length, (except trapezoidal thread): the length from the starting point of the thread (pipe end) to the vanishing point;

(2) Thread height: the distance from the top of the thread to the bottom of the thread;

(3) Pitch: the distance in the axial direction from any point of the thread to the corresponding point of the adjacent tooth;

(4) Thread taper: The change in thread diameter per inch of thread length, expressed in inches;

(5) Close distance: the distance measured in the axial direction from the end face of the pipe or coupling to the tightening position of the ring gauge or plug gauge;

(6) Thread tail taper (only some trapezoidal threads): The rapid retreat of the tool causes a steep slope at the end of the thread.

USI Steel is a professional API oil casing manufacturer in China, integrating warehousing, sales, processing and distribution. If you have related requirements, please contact: sales@usisteels.com