The national standard spiral steel pipe is made from strip steel coils, formed through normal temperature extrusion, and then welded using the automatic double-spiral double-sided submerged arc welding process to create spiral seam steel pipes. The strip steel is fed into the pipe welding unit, where it undergoes multiple passes of roller rolling, gradually forming a circular billet with an opening gap. The pressure of the extrusion roller is adjusted to control the weld gap between 1~3mm, ensuring that the ends of the weld are flush.

(1) Raw materials include steel coils, welding wire, and 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. After rolling into steel pipes, automatic submerged arc welding is used for reinforcement.

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

(4) The pressure on the conveying machine's cylinders on both sides is controlled by an electrical contact pressure gauge, ensuring smooth and even steel strip conveyance.

(5) Utilizing externally or internally controlled roller forming.

(6) Employ a weld gap control device to ensure the weld gap meets welding requirements, with strict control over pipe diameter, misalignment, and weld gap.

(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焊ed 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 marking is applied, allowing production workers to adjust process parameters in real-time and promptly eliminate the defects.

(9) Single steel pipes are cut using an air plasma cutting machine. National Standard Spiral Steel Pipe, Manufacturer of National Standard Spiral Steel Pipe, Price of National Standard Spiral Steel Pipe

(10) After cutting the steel pipes into individual pieces, each batch must undergo a stringent initial inspection system, checking the mechanical properties of the welds, chemical composition, fusion condition, surface quality of the pipes, and undergo non-destructive testing to ensure the pipe-making process is qualified before being officially put into production.

(11) Areas with continuous ultrasonic flaw detection markings on the welds should undergo manual ultrasonic and X-ray re-inspection. If defects are confirmed, they should be repaired and re-inspected by non-destructive testing until the defects are eliminated.

(12) All pipes with butt welds of strip steel or T-joints intersecting helical welds have been subjected to X-ray television or film inspection.

(13) Each steel pipe undergoes hydrostatic testing with radial sealing. Both 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) Precision machining at pipe ends to ensure accurate control of end face perpendicularity, bevel angle, and burr.