Pile spiral weld steel pipe is made of hot-rolled steel strip coil as pipe billet, often temperature spiral forming, and made of double-sided submerged arc welding or high-frequency welding. It is used for steel pipe used in civil building structure, wharf, bridge and other foundation piles. The main reference standard is SY/T5040-2008 (spiral weld steel pipe for pile). Pipe diameter range: diameter of 325mm-2400mm, wall thickness range 8-60mm, length range 6-12m.
The spiral steel pipe used for pile driving is a spiral seam steel pipe welded by automatic double-wire double-sided submerged arc welding process with strip coil plate as the raw material and extruded at constant temperature.
Process flow :
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(1) Raw materials, namely strip coil, welding wire and flux. Strict physical and chemical tests must be carried out before being put into operation.
(2) Strip steel head and tail butt, single wire or double wire submerged arc welding, automatic submerged arc welding after coil steel pipe repair welding.
(3) Before forming, strip steel is straightened, edging, planing, surface cleaning, conveying and bending.
(4) The electric contact pressure gauge is used to control the pressure of the oil cylinder on both sides of the conveyor to ensure the smooth transmission of strip steel.
(5) Adopt external control or internal control roller forming.
(6) The weld gap control device is adopted to ensure that the weld gap meets the welding requirements, and the pipe diameter, the amount of wrong side and the weld gap are strictly controlled.
(7) Both internal and external welding adopts Lincoln welding machine for single wire or double wire submerged arc welding, so as to obtain stable welding quality.
(8) The welds after welding are inspected by online continuous ultrasonic automatic injury instrument to ensure 100% non-destructive testing coverage of spiral welds. If there is any defect, it will automatically alarm and spray mark, and the production workers will adjust the process parameters at any time to eliminate the defect in time.
(9) Use air plasma cutting machine to cut the steel pipe into a single.
(10) After cutting into a single steel pipe, each batch of steel pipe shall undergo a strict first inspection system to check the mechanical properties of the weld, chemical composition, melting condition, surface quality of the steel pipe and non-destructive testing to ensure that the pipe making process is qualified before it can be formally put into production.
(11) The parts with continuous acoustic flaw detection mark on the weld shall be reviewed by manual ultrasonic and X-ray. If there are defects, after repair, they shall be nondestructive test again until it is confirmed that the defects have been eliminated.
(12) The butt welding welds of strip steel and the pipes where the T-joint intersects with the spiral welds are all inspected by X-ray TV or film.
(13) Each steel pipe is tested by hydrostatic pressure, and the pressure is sealed radial. The test pressure and time are strictly controlled by the microcomputer detecting device of steel pipe water pressure. Test parameters are automatically printed and recorded.
(14) Pipe end machining, so that the end face perpendicularity, groove Angle and blunt edge can be accurately controlled.
