Spiral steel pipe thread in the production process in accordance with the provisions of API standards using threaded fastening test screw tightness, according to a certain test cycle using single-threaded drilling tool pitch and taper for testing.
Use the site has been worn thread can be used to check the tooth profile tooth wear, the remaining tooth width is not less than the original tooth width of 1/2, the remaining tooth top height of not less than 2/3, grinding tooth is not greater than 3.5 teeth, thread can continue Use, or should be withholding treatment.
The most effective way to identify the threads on the helix is to use a joint ruler, which is a special marked vernier caliper with a diameter of the root of the outer helical pipe and the diameter of the tapered bore of the internal thread. It is simple, intuitive and accurate. In addition, you can directly use the long vernier caliper with a steel ruler to measure the root diameter of the external thread, length, screw diameter, in order to expand the tapered control thread size query.
The thread is placed vertically and the direction of the screw upwards can be recognized from the front. The thread rotates, rising right to the right, and left to the left.
The three-digit representation of the drill thread is the name of the joint specified in the Metallurgical Industry Standard SYB12604-63. The first number indicates the nominal size of the joint, the second number indicates the type of joint, and the third number indicates the inside and outside of the joint thread.
Spiral steel pipe and ordinary steel race
Spiral steel pipe is divided into cold-drawn and hot-rolled, but the surface is not to deal with several sub-seamless pipe, with its material and the implementation of standards, the material is ordinary pipe, alloy pipe, the implementation of standards 1, seamless steel pipe: GB8162-992 5, fertilizer equipment, high-pressure seamless steel pipe: GB6479-999, the boiler seamless pipe: GB5163-99 3, boiler seamless steel pipe: GB3087-1999 4, boiler high-pressure seamless pipe: GB5310-95 (ST45.8-Ⅲ type) 1999 6, geological drilling seamless steel pipe: YB235-70 7, oil drilling seamless steel pipe: YB528-65 8, oil cracking seamless steel pipe: GB9948- 88 9, seamless drill casing: YB691-70 10, Seamless steel tube: GB3088-1999 11, seamless steel pipe: GB5312-1999 12, cold drawn precision cold-rolled seamless steel pipe: GB3639- 1999 13, a variety of alloy pipe 16Mn, 27SiMn, 15CrMo, 35CrMo, 12CrMo, 20G, 40Cr , 12Cr1MoV, 15CrMo steel production process is divided into two types of seamless steel tubes and welded steel pipe. Spiral steel pipe from the ingot, seamless steel pipe made of pipe rods or steel rod perforation; pipe is hot or cold rolled steel and strip welding, vertical seam welding can also be spiral welding.