SSAW steel pipe is strip steel coil as the raw material, warm-extruded, and welded by an automatic double-wire double-sided submerged arc welding process.

(1) The raw materials are strip coil, welding wire, and flux. Before going through the strict physical and chemical tests.

(2) Strip steel head-to-tail butt joint, single wire or double wire submerged arc welding, automatic submerged arc welding repair welding after rolling into steel pipe.

(3) Before forming, the strip is subjected to leveling, trimming, planing, surface cleaning and pre-bending.

(4) The electric contact pressure gauge is used to control the pressure of the cylinder on both sides of the conveyor to ensure the smooth conveyance of the strip.

(5) Roller molding with external control or internal control.

(6) Weld gap control device is used to ensure that the weld gap meets the welding requirements, and the pipe diameter, misalignment and weld gap are strictly controlled.

(7) Both internal and external welding are performed by single- or double-wire submerged arc welding using the Lincoln welding machine in the United States, so as to obtain stable welding specifications.

(8) The welded seams are inspected by an online continuous ultrasonic automatic flaw detector to ensure 100% non-destructive testing coverage of spiral welds. If there is a defect, it will automatically alarm and spray the mark, and the production workers will adjust the process parameters at any time to eliminate the defect in time.

(9) The steel pipe is cut into individual pieces by an air plasma cutting machine.

(10) After cutting into a single steel pipe, each batch of steel pipes must undergo a strict first inspection system to check the mechanical properties, chemical composition, fusion status, surface quality of the steel pipe and non-destructive inspection to ensure that the pipe manufacturing process is qualified. Only then can it be officially put into production.

(11) The parts with continuous sonic flaw detection marks on the welds are reviewed by manual ultrasonic and X-rays. If there are defects, after repairing, they undergo non-destructive inspection again until it is confirmed that the defects have been eliminated.

(12) All pipes where steel butt welds and tee joints intersect with spiral welds are inspected by X-ray television or film.

(13) Each steel pipe is subjected to a hydrostatic test, and the pressure is radial sealed. The test pressure and time are strictly controlled by the steel tube hydraulic pressure testing device. The test parameters are printed automatically.

(14) The pipe end is machined to accurately control the end face verticality, bevel angle and blunt side.