The national standard spiral steel pipe is made from steel coil as raw material, formed through cold extrusion, and welded using the automatic double-sided submerged arc welding process. The spiral steel pipe involves feeding the steel strip into the welding pipe unit, passing through multiple roller rolls, gradually rolling up the steel strip to form a circular billet with an opening gap. The pressure of the extrusion roller is adjusted to control the weld gap between 1~3mm and ensure the ends of the weld are flush.

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

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

(3) Prior to forming, the strip steel is processed through leveling, trimming, edging, surface cleaning conveyance, and pre-bending edge treatment.

(4) The pressure on the conveying machine's cylinder is controlled by an electric contact pressure gauge, ensuring smooth steel strip transportation.

(5) Utilize externally or internally controlled roller forming.

(6) Utilize a weld gap control device to ensure the weld gap meets welding requirements; the pipe diameter, misalignment, and weld gap are all strictly controlled.

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

(8) All welded seams undergo online continuous ultrasonic automatic flaw detection, ensuring full coverage of non-destructive testing for spiral welds. In case of defects, an automatic alarm is triggered and marked with paint, allowing production workers to adjust process parameters in real-time and promptly eliminate defects.

(9) Cut steel pipes into individual lengths using an air plasma cutting machine. National Standard Spiral Steel Pipe, National Standard Spiral Steel Pipe Manufacturer, National Standard Spiral Steel Pipe Price

(10) After cutting into individual steel pipes, each batch must undergo a rigorous initial inspection process. This includes checking the mechanical properties, chemical composition, fusion condition, surface quality of the pipes, and undergoing non-destructive testing to ensure the pipe-making process is qualified before it can be officially produced.

(11) Areas with continuous ultrasonic flaw detection marks 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) All pipes with weld seams of steel strips or T-joints intersecting helical seams have been inspected by X-ray television 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 microcomputer 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.