Application of drilling thread of thick wall spiral steel pipe

　　In the production process of the drilling thread of thick wall spiral steel pipe, the thread working gauge is used to check the thread tightness according to the API standard, and the single detector of drilling thread is used to check the thread pitch and taper according to a certain inspection cycle.

　　The worn thread can be checked by using the profile gauge on the site. The remaining crown width is not less than 1 / 2 of the original crown width, the remaining crown height is not less than 2 / 3 of the original crown height, and the thread can still be used when the number of worn teeth is not more than 3.5. Otherwise, the thread shall be repaired.

　　The most effective way to identify the screw thread of ASTM A106 28 Inch SSAW Spiral Steel Pipe in the field is to use joint ruler, which is a vernier caliper specially marked with the root diameter of external thread and the taper hole diameter of internal thread. In addition, the long foot vernier caliper and steel ruler can be directly used to measure the outer diameter, length of the root of the external thread, and the tapered hole diameter of the internal thread to check the thread specification.

　　When the thread is placed vertically, the thread rotation direction can be determined by looking at the rising direction of the helix from the front, which is right when it rises to the right and left when it rises to the left.

　　The three digit representation of drilling tool thread is the joint code specified in the standard syb12604-63 of the Ministry of metallurgical industry. The first digit represents the general dimension of joint, the second digit represents the type of joint, and the third digit represents the internal and external thread of joint.