Q345 Spiral Welded Pipe
Spiral seam submerged arc welded steel pipe (SY5036-83) for pressure-bearing fluid transportation is mainly used for pipelines for transporting oil and natural gas; spiral seam high-frequency welded steel pipe (SY5038-83) for pressure-bearing fluid transportation, using high-frequency lap welding method Welded, spiral seam high-frequency welded steel pipe for pressure-bearing fluid transportation. 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 by double-sided automatic submerged arc welding or single-sided welding for water, Submerged arc welded steel pipe for conveying general low pressure fluid such as gas, air and steam
(1) Raw materials are strip steel coils, welding wires, and fluxes. Strict physical and chemical inspections are required before investment.
(2) Butt joint of strip steel head and tail, adopt single wire or double wire submerged arc welding, after coiling into steel pipe, adopt automatic submerged arc welding to repair welding.
(3) Before forming, the strip undergoes leveling, edge trimming, edge planing, surface cleaning and conveying, and pre-bending treatment.
(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 welding seam gap control device is used to ensure that the welding seam gap meets the welding requirements, and the pipe diameter, the amount of misalignment and the welding seam gap are all strictly controlled.
(7) Both internal welding and external welding adopt American Lincoln electric welding machine for single-wire or double-wire submerged arc welding, so as to obtain stable welding specifications.
(8) The welded seams are all inspected by an online continuous ultrasonic automatic flaw instrument, which guarantees 100% non-destructive testing coverage of 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 according to this to eliminate the defect in time.
(9) Air plasma cutting machine is used to cut the steel pipe into individual pieces.
(10) After cutting into single 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 pass non-destructive inspections to ensure that the pipe-making process is qualified. After that, it can be officially put into production.
(11) The parts with continuous sonic flaw detection marks on the weld are re-examined by manual ultrasonic and X-ray. If there is a defect, after repairing, it will go through non-destructive inspection again until it is confirmed that the defect has been eliminated.
(12) The pipes where the strip steel butt welding seams and the D-shaped joints intersecting the spiral welding seams are all inspected by X-ray television or filming.
(13) Each steel pipe undergoes hydrostatic pressure test, and the pressure adopts radial seal. The test pressure and time are strictly controlled by the steel pipe hydraulic microcomputer detection device. The test parameters are automatically printed and recorded.
(14) The pipe end is mechanically processed, so that the verticality of the end face, the bevel angle and the obtuse edge can be accurately controlled.
At present, the commonly used standards for spiral steel pipes are generally divided into: SY/T5037-2000 (Ministry standard, also called spiral seam submerged arc welded steel pipe for ordinary fluid transportation pipelines), GB/T9711.1-1997 (National standard, also called oil and gas industrial transportation The first part of the technical delivery conditions of steel pipes: Grade A steel pipes (the most stringent requirements are GB/T9711.2 Grade B steel pipes), API-5L (American Petroleum Institute, also called pipeline steel pipes; it is divided into two types: PSL1 and PSL2 Grade), SY/T5040-92 (Spiral submerged arc welded steel pipe for pile)
Spiral tube material: Q235A, Q23b, 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb. Q345 L245 L290 X42 X46 X70 X80
Spiral steel pipes are mainly used in water supply engineering, petrochemical industry, chemical industry, electric power industry, agricultural irrigation, and urban construction. It is one of the 20 key products developed in my country.
Used for liquid transportation: water supply, drainage. Used for gas transportation: coal gas, steam, liquefied petroleum gas. For structural purposes: as piling pipes, as bridges; piers, roads, building structures, etc.
