(1) Raw materials are strip steel coils, welding wires, and fluxes. Strict physical and chemical inspections are required before investment.
(2) Butt joint of strip steel head and tail, adopt single wire or double wire submerged arc welding, after coiling into steel pipe, adopt automatic submerged arc welding repair welding.
(3) Before forming, the strip undergoes leveling, edge trimming, edge planing, surface cleaning and conveying, and pre-bending treatment.
(4) The electric contact pressure gauge is 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 welding seam gap control device is adopted to ensure that the welding seam gap meets the welding requirements, and the pipe diameter, the amount of misalignment and the welding seam gap are all strictly controlled.
(7) 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 quality.
(8) The welded seams are all inspected by the online continuous ultrasonic automatic flaw instrument, which guarantees 100% non-destructive testing coverage of the spiral welds. If there is a defect, it will automatically alarm and spray the mark, and the worker can adjust the process parameters at any time to eliminate the defect in time.
(9) Use an air plasma cutting machine to cut the steel pipe into individual pieces.
(10) After cutting into single steel pipes, each batch of steel pipes must undergo a strict initial 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 that the pipe-making process is qualified. After that, it can be formally invested.
(11) The parts with continuous sonic flaw detection marks on the weld are re-examined by manual ultrasonic and X-ray. If there are defects, after repairing, they will go through non-destructive inspection again until it is confirmed that the defects have been eliminated.
(12) The pipes where the strip steel butt welds and the D-shaped joints intersecting with the spiral welds are all inspected by X-ray television or filming.
(13) Each steel pipe undergoes hydrostatic pressure test, and the pressure adopts radial seal. The test pressure and time are strictly controlled by the steel pipe hydraulic microcomputer detection device. The test parameters are automatically printed and recorded.
(14) The pipe end is machined to accurately control the verticality of the end face, the bevel angle and the obtuse edge.
