Spiral welded pipe equipment manufacturers describe the production process of spiral steel pipes

Spiral steel pipe production process: It is a spiral seam steel pipe made of strip steel coil as raw material, often warmly extruded, and welded by automatic double-wire double-sided submerged arc welding process.

(1) The raw materials are 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 strip steel are butted by single wire or double wire submerged arc welding, and automatic submerged arc welding is used for repair welding after rolling into a steel pipe.

(3) Before forming, the strip is leveled, trimmed, planed, surface cleaned and conveyed and pre-bending.

(4) The electric contact pressure gauge is used to control the pressure of the cylinders on both sides of the conveyor to ensure the smooth conveying of the strip.

(5) Adopt external control or internal control roll forming.

(6) The weld gap control device is used to ensure that the weld gap meets the welding requirements, and the pipe diameter, the amount of misalignment and the weld gap are strictly controlled.

(7) Lincoln welding machine is used for single wire or double wire submerged arc welding, so as to obtain stable welding specifications.

(8) The welded seams are all inspected by the online continuous ultrasonic automatic flaw tester, which ensures the highest non-destructive testing coverage of the spiral welds. If there is a defect, it will automatically alarm and spray the mark, and the production workers can adjust the process parameters at any time accordingly to eliminate the defect in time.

(9) Use an air plasma cutting machine to cut the steel pipe into single pieces.

(10) After cutting into a single steel pipe, the first three of each batch of steel pipes shall undergo a strict 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 parts with continuous sonic flaw detection marks on the welds shall be re-examined by manual ultrasonic wave and X-ray. If they are indeed defective, they shall be repaired and subjected to non-destructive inspection again until it is confirmed that the defects have been eliminated.

(12) The pipes where the butt welding seam of the strip steel and the T-joint intersecting with the spiral welding seam are located shall all be inspected by X-ray television or filming.

(13) Each steel pipe is tested by hydrostatic pressure, and the pressure is radially sealed. The test pressure and time are strictly controlled by the steel pipe water pressure microcomputer detection device. The test parameters are automatically printed and recorded.

(14) The pipe end is machined so that the verticality of the end face, the bevel angle and the blunt edge are accurately controlled.

The characteristics of the spiral steel pipe: the production process of the straight seam welded pipe is simple, the production efficiency is high, the cost is low, and the development is fast. The strength of the spiral welded pipe is generally higher than that of the straight seam welded pipe. However, compared with the straight seam pipe of the same length, the length of the weld is increased by 30 to 50 times, and the production speed is lower. Therefore, most of the welded pipes with smaller diameters use straight seam welding, and most of the welded pipes with large diameters use spiral welding.

Spiral pipe and its standard classification: Spiral seam submerged arc welded steel pipe (SY5036-83) for conveying oil and gas under pressure; Spiral seam high frequency welded steel pipe (SY5038-83) for conveying pressure fluid Spiral seam high-frequency welded steel pipe for pressurized fluid transportation, welded by high-frequency lap welding. The steel pipe has strong pressure bearing capacity and good plasticity, which is convenient for welding and processing. Generally, the spiral seam submerged arc welded steel pipe (SY5037-83) for low-pressure fluid transportation is made of double-sided automatic submerged arc welding or single-sided welding. Submerged arc welded steel pipes for general low-pressure fluid transportation such as gas, air and steam. Now the commonly used standards for spiral steel pipes are generally divided into: SY/T5037-2000 (Ministry Standard, also known as spiral seam submerged arc welded steel pipes for ordinary fluid transportation pipelines), GB /T9711.1-1997 (national standard, also known as delivery technical conditions for petroleum gas industry transmission steel pipes: steel pipes), API-5L (Petroleum Association, also known as pipeline steel pipes), SY/T5040-92 (spiral seam submerged arc for piles welded steel pipe)