(1) Raw materials are steel coils, welding wire, and flux. Have to go through rigorous physical and chemical tests before investing.
(2) The head and tail butt of the steel strip adopts monofilament or double wire submerged arc welding and adopts automatic submerged arc welding to repair welding after being rolled into steel pipe.
(3) Before forming, the steel strip is leveled, trimmed, edged, surface cleaned and pre-flanged.
(4) The electric contact pressure gauge is used to control the pressure of the compression cylinders on both sides of the conveyor to ensure the smooth delivery of the strip.
(5) 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 the pipe diameter, the amount of misalignment, and the weld gap are all strictly controlled.
(7) The inner and outer welds are all welded by single-wire or double-wire submerged arc welding using the Lincoln Electric Welder of the United States, so as to obtain stable welding quality.
(8) Welded welds were all inspected by an online continuous ultrasonic automatic flaw tester to ensure a non-destructive test coverage of 100% spiral welds. If there are defects, they will be automatically alarmed and painted. The production workers will adjust the process parameters at any time to eliminate defects in time.
(9) Using an air plasma cutter to cut the steel pipe into single pieces.
(10) After cutting into single steel pipes, each batch of steel pipes shall be subjected to a strict first inspection system to check the mechanical properties, chemical composition, fusion condition of the welds, the surface quality of the steel pipes, and non-destructive inspections to ensure the quality of the pipe-making process. After they can be formally put into production.
(11) Where there is a continuous sound wave flaw detection mark on the weld, after manual ultrasonic and X-ray review, if there is a defect, after repair, it shall be subjected to non-destructive testing again until it is confirmed that the defect has been eliminated.
(12) The butt joints of the butt welds and the intersections with the spiral welds of the steel strip are all examined by X-ray television or film.
(13) Each pipe is hydrostatically tested and the pressure is sealed with a radial seal. The test pressure and time are strictly controlled by the steel pipe hydraulic pressure testing device. Test parameters are automatically printed and recorded.
(14) End-of-pipe machining is performed so that the verticality of the end face, the groove angle and the blunt edge are accurately controlled.
