Production process of spiral steel pipe

(1) Raw materials are strip steel coils, welding wires, and fluxes. Before putting into use, they must go through strict physical and chemical tests.

(2) The head-to-tail butt joint of strip steel adopts single-wire or double-wire submerged arc welding, and automatic submerged arc welding is used for repair welding after being rolled into steel pipes.

(3) Before forming, the strip steel is leveled, trimmed, planed, surface cleaned, transported, and pre-bent.

(4) Electric contact pressure gauges are used to control the pressure of the cylinders on both sides of the conveyor to ensure the smooth conveying of the strip.

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

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

(7) Both internal and external welding adopt American Lincoln electric welding machines for single-wire or double-wire submerged arc welding, to obtain stable welding specifications.

(8) The welded seams are all inspected by the online continuous ultrasonic automatic flaw detector, which ensures 100% non-destructive testing coverage of the spiral welds. If there is a defect, it will automatically alarm and spray the mark, and the production workers can adjust the process parameters at any time according to this to eliminate the defect in time.

(9) Cut the steel pipe into single pieces with an air plasma cutting machine.

(10) After cutting into single steel pipes, each batch of steel pipes must undergo a strict first inspection system to check the mechanical properties, chemical composition, fusion status of the welds, steel pipe surface quality, and non-destructive testing to ensure that the pipe-making process is qualified After that, it can be officially put into production.

(11) The parts marked by continuous acoustic wave flaw detection on the weld seam shall undergo manual ultrasonic and X-ray re-examination. If there are indeed defects, after repairing, they shall undergo non-destructive inspection again until the defects are confirmed to be eliminated.

(12) The pipes where the strip steel butt welds and the D-shaped joints intersected with the spiral welds are all inspected by X-ray TV or film.

(13) Each spiral steel pipe has passed the hydrostatic pressure 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 end of the spiral steel pipe is machined, so that the verticality of the end face, the groove angle, and the blunt edge are accurately controlled.