Spiral steel pipe is a spiral seam steel pipe with steel coil plate as raw material

Spiral steel pipe is a spiral seam steel pipe with steel coil plate as raw material, and welded by automatic double-wire double-sided submerged arc welding process. The main production process is described as follows:

(1) Raw materials are strip steel coil, welding wire and flux. It must go through strict physical and chemical tests before input.

(2) Belt steel head and tail docking, using single wire or double wire buried arc welding, and using automatic buried arc welding and supplementary welding after rolling into the steel pipe.

(3) Before forming, the strip through leveling, cutting edge, cutting edge, surface cleaning and pre-bending edge treatment.

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(4) The electric connection pressure gauge is used to control the pressure of the oil cylinder on both sides of the conveyor to ensure the smooth transmission of the strip steel.

(5) Adopt external control or internal control roller forming.

(6) The weld gap control device is adopted to ensure that the weld gap meets the welding requirements, and the pipe diameter, the amount of wrong edges and the weld gap are strictly controlled.

(7) Internal welding and external welding are used for single wire or double wire submerged arc welding, so as to obtain stable welding specifications.

(8) The welded welds are checked by the online continuous ultrasonic automatic flaw detector, which ensures the nondestructive testing coverage of 100% spiral welds. If there is a defect, alarm automatically and spray marks, and the production workers can adjust the process parameters at any time to eliminate the defects in time.

(9) Use the air plasma cutting machine to cut the steel pipe into single roots.

(10) After cutting into a single steel pipe, the first three of each batch of steel pipe should undergo strict first inspection system to check the mechanical properties, chemical composition, dissolution status, surface quality of the steel pipe and non-destructive flaw inspection to ensure that the pipe making process is qualified before being formally put into production.

(11) The parts with continuous acoustic wave detection mark on the weld, after manual ultrasonic and X-ray review, if there is any defect, after repair, through nondestructive inspection again, until it is confirmed that the defect has been eliminated.

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(12) The pipe where the strip butt welding weld and the D-shaped joint that intersects the spiral weld are all inspected by X-ray TV or film.

(13) Each steel pipe passes through the hydrostatic test, and the pressure is radially sealed. The test pressure and the time are strictly controlled by the steel pipe water pressure microcomputer detection device. Automatic print record of test parameters.

(14) Pipe end machining, so that the end surface verticality, slope mouth and blunt edge to be accurate control.