The national standard spiral steel pipe is a helical seam steel pipe made from steel strip coils, which is formed by warm extrusion and焊接 using the automatic double-sided submerged arc welding process. The steel strip is fed into the pipe welding unit, rolled by multiple roller stands, gradually coiling to form a circular billet with an open gap. The pressure of the extrusion roller is adjusted to control the weld gap between 1~3mm, and to ensure the ends of the weld are flush.

(1) Raw materials include steel coils, welding wire, and welding flux. All must undergo rigorous physical and chemical inspections before use.

(2) Steel strip ends are joined using single or double wire submerged arc welding, followed by automatic submerged arc welding for reinforcement after rolling into steel pipes.

(3) Prior to forming, the steel strip is straightened, trimmed, deburred, cleaned, conveyed, and pre-bent.

(4) The electrical contact pressure gauge is used to control the pressure of the hydraulic cylinders on both sides of the conveyor, ensuring smooth and even steel strip conveyance.

(5) Utilize external or internal roll forming.

(6) Utilize a weld gap control device to ensure the weld gap meets welding requirements; strict control is applied to pipe diameter, misalignment, and weld gap.

(7) Both inner and outer welds are performed using Lincoln welding machines for single or double wire submerged arc welding, ensuring consistent welding quality.

(8) All welded seams are inspected by an online continuous ultrasonic flaw detector, ensuring full coverage of non-destructive testing for spiral seams. In case of any defects, an automatic alarm is triggered and a marking is sprayed, allowing production workers to adjust process parameters in real-time and promptly eliminate defects.

(9) Cut steel pipes individually using an air plasma cutting machine. GB Spiral Steel Pipe, GB Spiral Steel Pipe Manufacturer, GB Spiral Steel Pipe Price

(10) After cutting into individual steel pipes, each batch must undergo a rigorous initial inspection process, checking the mechanical properties of the welds, chemical composition, fusion condition, surface quality of the steel pipes, and non-destructive testing to ensure the pipe manufacturing process is qualified before formal production can commence.

(11) Areas with continuous ultrasonic flaw detection markings on the welds are subject to manual ultrasonic and X-ray re-inspection. If defects are confirmed, they are repaired and re-inspected non-destructively until the defects are eliminated.

(12) The pipes at the location of the welded seams of the strip steel and the T-joints intersecting with the spiral welds have all undergone X-ray television inspection or filming.

(13) Each steel pipe undergoes hydrostatic testing with radial sealing. The test pressure and time are strictly controlled by the steel pipe water pressure computerized detection device. Test parameters are automatically printed and recorded.

(14) Machining at the pipe end ensures precise control of the end face perpendicularity, bevel angle, and burr.