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Spiral steel pipe processing technology
Feb 11, 2019

Spiral steel tube is a kind of spiral welded steel tube which is made of strip steel coil as raw material, often formed by warm extrusion, and welded by automatic double wire and double submerged arc welding process.

The following is a brief introduction of the manufacturing process of spiral steel tube:The raw materials are strip coil, wire and flux.Before being put into operation, it must pass strict physical and chemical inspection.Single wire or double wire submerged arc welding shall be adopted for the butt joint of strip head and tail, and automatic submerged arc welding shall be adopted after the steel pipe is rolled.Before forming, the strip is straightened, cut and planed, and the surface is cleaned, transported and bent.The electric contact pressure gauge is used to control the pressure of pressing down the oil cylinder on both sides of the conveyor to ensure the smooth conveying of the steel strip.Adopt external control or internal control roller forming.The weld gap control device is used to ensure that the weld gap meets the welding requirements.

Lincoln welder is used for single wire or double wire submerged arc welding, so as to obtain stable welding quality.The finished welds are checked by the continuous ultrasonic automatic flaw detector online, which ensures 100% coverage of the spiral welds in nondestructive testing.If there are defects, automatic alarm and spray mark, production workers according to this at any time to adjust the process parameters, eliminate defects in time.Air plasma cutting machine is used to cut the steel pipe into single root.After cutting into single steel tubes, each batch of steel tubes shall be subject to a strict first-inspection system to check the mechanical properties, chemical composition, melting state, surface quality of steel tubes and nondestructive inspection to ensure that the pipe making process is qualified before it can be formally put into production.The part marked by continuous acoustic wave inspection on the weld shall be subject to manual ultrasonic inspection and X-ray reexamination. If there is any defect, it shall be subject to nondestructive inspection again after repair until it is confirmed that the defect has been eliminated.The pipe where the butt weld of the strip and the t-joint intersecting the spiral weld are located shall be inspected by X-ray television or film.Each steel tube through hydrostatic test, pressure using radial seal.The test pressure and time are strictly controlled by the microcomputer testing device of water pressure of steel tube.Test parameters are automatically printed.The pipe end is machined so that the verticality, bevel Angle and blunt edge can be controlled accurately.