Helix steel pipes are spiral seam steel tubes made from strip steel coils, which are shaped through normal temperature extrusion and then焊接 using the automatic double-sided submerged arc welding process. The strip steel is fed into the pipe welding machine, 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 at 1~3mm, ensuring both ends of the weld are flush.
Production Process
(1) Raw materials include steel coils, welding wire, and welding flux. All must undergo rigorous physical and chemical testing 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 patch welding.
(3) Prior to forming, the steel strip undergoes leveling, trimming, edge dressing, surface cleaning conveyance, and pre-bending processing.
(4) The electric contact pressure gauge controls the pressure of the hydraulic cylinders on both sides of the conveyor, ensuring smooth steel strip transport.
(5) Utilizing external or internal roll forming.
(6) Employ 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 inner and outer welds are performed using Lincoln USA welding machines for single or double wire flux cored welding, ensuring consistent welding quality.
(8) All welded seams are inspected by an online continuous ultrasonic flaw detector, ensuring full non-destructive testing coverage 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 the defects.
(9) Cut steel pipes individually using an air plasma cutting machine.
(10) After cutting into individual steel pipes, each batch must undergo a stringent initial inspection process, checking the mechanical properties of the welds, chemical composition, fusion status, 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 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 T-joints intersecting the longitudinal welds of the strip steel have been inspected with X-ray television or film.
(13) Each steel pipe undergoes hydrostatic testing with radial sealing. The test pressure and time are strictly controlled by the steel pipe water pressure computer 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.
Process Features
Key Process Features of Spiral Steel Pipe:
During the molding process, steel plates deform uniformly with minimal residual stress and no surface scratches are produced. The processed spiral steel pipes offer greater flexibility in diameter and wall thickness specifications, particularly in the production of high-grade thick-walled pipes, especially medium and small diameter thick-walled pipes, where they possess advantages that other processes cannot match, and can meet users' more varied requirements for spiral steel pipe specifications.
b. Utilizes advanced double-sided submerged arc welding technology, enabling welding in position with minimal defects such as misalignment, welding offset, and incomplete fusion, ensuring easy control over welding quality.
c. Quality inspections for steel pipes ensure the entire production process is under effective testing and monitoring, thereby effectively guaranteeing product quality.
d. The entire production line's equipment is capable of connecting to a computer data collection system, enabling real-time data transmission and centralized control room monitoring of technical parameters during the production process.
