(1) The head and tail of the steel pipe
are butt jointed by single-wire or double-wire submerged arc welding. After the steel pipe is coiled, it is repaired by automatic submerged arc welding.
(2) Before forming, the steel pipe undergoes flattening, edge trimming, edge planing, surface cleaning and conveying, and pre-curving.
(3) Electric contact pressure gauges are used to control the pressure of the cylinders on both sides of the conveyor to ensure the smooth transportation of steel pipes.
(4) The steel pipe is cut into individual steel pipes with an air plasma cutting machine.
(5) After cutting into a single steel pipe, the first three steel pipes of each batch must undergo a strict first inspection system to check the mechanical properties, chemical composition, fusion status of the weld, the surface quality of the steel pipe and pass non-destructive inspection to ensure the pipe manufacturing process Only after it is qualified can it be officially put into production.
(6) The parts with continuous sonic flaw detection marks on the welds are re-examined by manual ultrasonic and X-ray. If there are defects, after repairing, they will go through non-destructive inspection again until the defects are confirmed.
(7) adopts external control or internal control roll forming.
(8) The weld gap control device is used to ensure that the weld gap meets the welding requirements, and the pipe diameter, the amount of misalignment and the weld gap are strictly controlled.
(9) Both internal welding and external welding adopt American Lincoln electric welding machine for single-wire or double-wire submerged arc welding, so as to obtain stable welding specifications.
(10) All welds after welding are inspected by an online continuous ultrasonic automatic flaw instrument, which guarantees 100% non-destructive testing coverage of 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 to eliminate the defect in time.
(11) The butt weld of the steel pipe and the pipe where the T-shaped joint intersects with the spiral weld is all inspected by X-ray television or filming.
(12) Each steel pipe undergoes hydrostatic pressure test, and the pressure adopts radial seal. Test pressure and time are strictly controlled by the steel pipe hydraulic microcomputer testing device.
(13) The pipe end is machined to accurately control the verticality of the end face, the bevel angle and the obtuse edge.