The performance of alloy steel pipe is much higher than that of ordinary seamless steel pipe.
(1) Raw materials are strip steel coils, welding wires, and fluxes. Before putting into use, they must go through strict physical and chemical tests.
(2) The head-to-tail butt joint of strip steel adopts single-wire or double-wire submerged arc welding, and automatic submerged arc welding is used for repair welding after being rolled into steel pipes.
(3) Before forming, the strip steel is leveled, trimmed, planed, surface cleaned, transported, and pre-bent.
(4) Electric contact pressure gauges are 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 weld gap control device is used to ensure that the weld gap meets the welding requirements and that the pipe diameter, misalignment amount, and weld gap are strictly controlled.
(7) Both internal welding and external welding use American Lincoln welding machines for single-wire or double-wire submerged arc welding, to obtain stable welding specifications.
(8) The welded seams are all inspected by the online continuous ultrasonic automatic flaw detector, which ensures 100% non-destructive testing coverage of the 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 according to this to eliminate the defect in time.
(9) Use an air plasma cutting machine to cut the steel pipe into single pieces.
(10) After cutting into single steel pipes, 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 pipes, and non-destructive testing to ensure the quality of the pipe-making process. Only after passing the test can it be formally put into production.
(11) The part marked by continuous ultrasonic flaw detection on the weld shall undergo manual ultrasonic and X-ray re-examination. If there is a defect, after repair, it shall undergo non-destructive inspection again until it is confirmed that the defect has been eliminated.
(12) The tubes where the strip steel butt welds and the D-joints intersected with the spiral welds are all inspected by X-ray TV or film.
(13) Each steel pipe has passed the hydrostatic pressure test, and the pressure is radially sealed. The test pressure and time are strictly controlled by the steel pipe water pressure 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 blunt edge. Because this kind of steel pipe contains a lot of Cr, its high-temperature resistance, high-temperature resistance, and corrosion resistance are incomparable to other seamless steel pipes, so alloy pipes are more useful in petroleum, chemical, electric power, boiler, and other industries. power throughout. China Steel Pipe Information Port Market Information
Post time: Jun-15-2023