Introduction to the production steps of spiral steel pipes

How to produce various types of spiral steel pipes from a piece of steel?


(1) Various inspections are carried out on the raw materials. Raw materials generally refer to strip steel coils, welding wires, flux, etc. They must undergo strict physical and chemical inspections before being put into use to ensure quality.
(2) The head and tail of the strip steel are butt-jointed, and single-wire or double-wire submerged arc welding is used. After the steel pipe is rolled, automatic submerged arc welding is used for repair welding.
(3) Processing is carried out. Before forming, the required steel is leveled, trimmed, planed, surface cleaned, conveyed, and pre-bent.
(4) An electric contact pressure gauge is used to control the pressure of the oil cylinder on both sides of the conveyor to ensure the smooth conveying of the strip steel.
(5) External or internal control roller forming is used.
(6) A weld gap control device is used to ensure that the weld gap meets the welding requirements. The pipe diameter, misalignment, and weld gap are strictly controlled.
(7) Both internal and external welding are performed by single-wire or double-wire submerged arc welding with the American Lincoln electric welder, thus obtaining stable welding specifications.
(8) The welds are inspected by online continuous ultrasonic automatic flaw detectors to ensure 100% non-destructive testing coverage of spiral steel pipes. If there are defects, an automatic alarm will be given and a spray mark will be applied. Production workers can adjust process parameters at any time to eliminate defects promptly.
(9) The steel pipes are cut into single pieces by an air plasma cutter.
(10) After being cut into single steel pipes, the first three steel pipes of each batch must undergo a strict first inspection system to check the mechanical properties, chemical composition, fusion status, surface quality of the welds, and non-destructive testing to ensure that the pipe making process is qualified before it can be officially put into production.
(11) The parts with continuous ultrasonic flaw detection marks on the welds are re-inspected by manual ultrasonic and X-ray. If there are defects, they will be repaired and then subjected to non-destructive testing again until it is confirmed that the defects have been eliminated.
(12) The butt welds of the strip steel and the T-joints intersecting the spiral welds are all inspected by X-ray television or film.
(13) Each steel pipe is subjected to a hydrostatic test, and the pressure is radially sealed. The test pressure and time are strictly controlled by the steel pipe water pressure microcomputer detection device. The test parameters are automatically printed and recorded.
(14) The pipe end is machined to accurately control the end face verticality, groove angle, and blunt edge.


Usually after the above 14 steps, a spiral steel pipe has been formed, but such a spiral steel pipe cannot be directly sent to the market. It is still necessary to inspect the quality of the spiral steel pipe and other aspects.