Spiral steel pipe for road piling

Spiral welded steel pipes for piles are made of hot-rolled steel strip coils as pipe blanks, often warmed and spirally formed, and made by double-sided submerged arc welding or high-frequency welding. They are used for steel pipes for foundation piles in civil construction structures, docks, bridges, etc. .

The spiral steel pipe for piling is a spiral seam steel pipe that is made of strip steel coils as raw materials, is extruded at regular temperatures, and welded by an automatic double-wire double-sided submerged arc welding 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 leveled, 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 smooth transportation of the strip.

(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 electric 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, ensuring 100% non-destructive testing coverage of spiral welds. If there is a defect, it will automatically alarm and spray mark, so that production workers can adjust the process parameters at any time to eliminate defects in time.

(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) The areas with continuous sonic flaw detection marks on the welds will undergo manual ultrasonic and X-ray re-examination. If there are indeed defects, they will be repaired and then undergo non-destructive inspection again until it is confirmed that the defects have been eliminated.

(12) The pipes where the strip butt welds and the T-shaped joints intersecting the spiral welds are located must be 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.