In the production process, the thread of the drill pipe of the spiral steel pipe is used to check the tightness of the thread according to the API standard. The pitch and taper are detected by the single thread detector of the drill thread according to a certain inspection cycle.
Use the on-site worn thread to check the wear of the thread with a dental profile. The remaining crest width is not less than 1/2 of the original crest width, and the remaining crest height is not lower than the original crest height 2/ 3. When the number of worn teeth does not exceed 3.5 teeth, the thread can still be used continuously, otherwise it should be repaired.
The most effective way to identify the thread of a spiral steel pipe is to use a joint ruler. This ruler is a vernier caliper with a diameter of the root of the external thread and the diameter of the taper hole of the internal thread. It is simple, intuitive and accurate. In addition, you can also directly use the long-foot vernier caliper combined with the steel ruler to measure the outer diameter, length and internal thread taper diameter of the external thread.
The thread is placed vertically, and the direction of the spiral rise from the front can be determined by the direction of the thread, rising to the right to the right, and to the left to the left. The three-digit representation of the thread of the drill is the code number specified in the standard SYB12604-63 of the Ministry of Metallurgical Industry. The first digit indicates the general size of the joint, the second digit indicates the type of the joint, and the third digit indicates the inside and outside of the joint thread.