Spiral steel pipe production process and straight seam steel pipe is different: the strip coil as raw material, often warm extrusion molding, automatic double-wire double-sided submerged arc welding process welded spiral seam steel pipe.
(1) Raw materials are steel coils, welding wire, and flux. Have to go through rigorous physical and chemical tests before investing.
(2) For the butt-end welding of steel strips, single-wire or double-wire submerged arc welding is used, and after the coils are made into steel pipes, automatic submerged arc welding is used to make up the welding.
(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, thereby obtaining a stable welding specification.
(8) Welded welds were all inspected by an online continuous ultrasonic automatic flaw tester to ensure non-destructive testing 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 a single steel pipe, a strict first inspection system shall be carried out for each of the first three pipes of each batch to inspect the mechanical properties, chemical composition, fusion condition, surface quality of steel pipes, and non-destructive testing to ensure the pipe-making process. Qualified before they can officially 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 undergo a non-destructive test 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 radial sealed. 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.