(1) The raw materials are steel strip coil, welding wire, and flux. They must undergo strict physical and chemical inspections before being put into use.
(2) For the head-to-tail butt joint of the steel strip, single-wire or double-wire submerged arc welding is used. After being rolled into a spiral steel pipe, automatic submerged arc welding is used for repair welding.
(3) Before forming, the strip steel undergoes leveling, trimming, planing, surface cleaning, transportation, and pre-bending.
(4) Electric contact pressure gauges control the pressure of the cylinders on both sides of the conveyor to ensure smooth conveying of the strip.
(5) Adopt external control or internal control roller forming.
(6) A weld gap control device is used to ensure that the weld gap meets the welding requirements. The pipe diameter, offset amount, and weld gap are strictly controlled.
(7) Both internal and external welding use electric welding machines for single-wire or double-wire submerged arc welding to obtain stable welding specifications.
(8) All completed welds have been inspected by an online continuous ultrasonic automatic flaw detector, ensuring 100% non-destructive testing coverage of spiral welds. If there is a defect, it will automatically alarm and spray mark, so that production workers can adjust the process parameters to eliminate defects in time.
(9) Use an air plasma cutting machine to cut the spiral steel pipe into individual pieces.
(10) After cutting into a single spiral steel pipe, each batch of spiral steel pipes must undergo a strict first inspection system to check the mechanical properties, chemical composition, fusion status of the weld, the surface quality of the spiral steel pipe, and non-destructive testing to ensure that the manufacturing process is only after the piping process is qualified can it be officially put into production.
(11) The areas with continuous sonic flaw detection marks on the welds will undergo manual ultrasonic and X-ray re-examination. If there are indeed defects, they will be repaired and then undergo non-destructive inspection again until it is confirmed that the defects have been eliminated.
(12) The steel strip butt welds and the pipes where the T-shaped joints intersect with the spiral welds are all inspected by X-ray television or film.
(13) Each spiral steel pipe has been tested by hydrostatic pressure, and the pressure is radially sealed. The spiral steel pipe water pressure microcomputer detection device strictly controls the test pressure and time. Test parameters are automatically printed and recorded.
(14) The pipe end is machined to accurately control the end face verticality, bevel angle, and blunt edge.
Post time: Oct-10-2023