Raw materials are strip coils, welding wire, flux. Strict physical and chemical testing is required before input.
The strip head and tail are butt jointed, and the monofilament or double wire submerged arc welding is adopted, and the automatic submerged arc welding repair welding is adopted after the coil is welded into the welded pipe.
Before forming, the strip is leveled, trimmed, planed, surface cleaned and pre-bent.
The electric contact pressure gauge is used to control the pressure of the cylinder on both sides of the conveyor to ensure the smooth conveying of the strip.
It adopts external control or internal control roll molding.
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 strictly controlled.
Both internal and external welding are performed by single-wire or double-wire submerged arc welding using a Lincoln electric welder in the United States to obtain stable welding quality.
The welded welds are inspected by online continuous ultrasonic automatic injury inspection, which guarantees the non-destructive testing coverage of 100% spiral welds. If there is a defect, the alarm is automatically alarmed and sprayed, and the production worker adjusts the process parameters at any time to eliminate defects in time.
The welded pipe was cut into individual pieces using an air plasma cutter.
After cutting into a single welded pipe, each batch of welded pipe shall be subjected to a strict first inspection system to check the mechanical properties, chemical composition, fusion condition, surface quality of the welded pipe and non-destructive testing to ensure that the pipe making process is qualified. Formally put into production.
The part of the weld with continuous acoustic flaw detection marks, after manual ultrasonic and X-ray review, if it is defective, after repair, it will pass the non-destructive test again until it is confirmed that the defect has been eliminated.
The tubes of the butt welds of the strip and the butt joints intersecting the spiral welds are all inspected by X-ray television or film.
Each welded pipe was subjected to hydrostatic pressure test and the pressure was sealed by radial. The test pressure and time are strictly controlled by the welded water pressure microcomputer detection device. The test parameters are automatically printed and recorded.
The pipe end is machined to make the end face verticality, groove angle and blunt edge accurately controlled.
Add: East Railway, North Yinhe Bridge, Beichen District, Tianjin, China
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