Spiral Welded Pipe Manufacturing Process

Introduction

Spiral steel pipe is a spiral seam steel pipe welded by automatic double-wire double-sided submerged arc welding process using strip steel coil as raw material, constant temperature extrusion molding.

Spiral Welded Pipe Manufacturing Process

(1) Raw materials include steel strip coil, welding wire and flux. They must undergo strict physical and chemical inspections before being put into use.
(2) The head and tail of the steel strip are butt-jointed using single-wire or double-wire submerged arc welding. After being rolled into a steel pipe, automatic submerged arc welding is used for repair welding.
(3) Before forming, the strip steel is straightened, trimmed, planed, surface cleaned, transported and pre-bent.
(4) Electric contact pressure gauges are used to control the pressure of the cylinders on both sides of the conveyor to ensure stable conveyance of strip steel.
(5) Adopt external control or internal control roller forming.
(6) A weld gap control device is used to ensure that the weld gap meets the welding requirements. The pipe diameter, offset amount and weld gap are all strictly controlled.
(7) Both internal and external welding use American Lincoln welding machines for single-wire or double-wire submerged arc welding to obtain stable welding quality.
(8) All completed welds have been inspected by an online continuous ultrasonic automatic flaw detector to ensure complete non-destructive testing coverage of spiral welds. If there are defects, the marks will be automatically sprayed and the production workers will adjust the process parameters at any time accordingly.
(9) Use an air plasma cutting machine to cut the steel pipe into individual pieces.
(10) After cutting into individual steel pipes, each batch of steel pipes must undergo a strict first inspection system to check the mechanical properties, chemical composition, fusion status of the welds, the surface quality of the steel pipes, and non-destructive testing to ensure that the pipe making process is qualified. Only then can it be officially put into production.
(11) There are areas with continuous acoustic flaw detection marks on the welds. After manual ultrasonic and X-ray re-examination, if there is a defect, it will be repaired and then go through non-destructive inspection again until the defect is confirmed to be gone.
(12) The pipes where the strip butt welds and the T-shaped joints that intersect the spiral welds are located have all been inspected by X-ray television or film.
(13) Each steel pipe has undergone a hydrostatic pressure test, and the pressure is radially sealed. 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) The pipe end is machined to accurately control the end face verticality, bevel angle and blunt edge.