Introduction to the production steps of spiral steel pipe

(1) Various inspections of raw materials are carried out. Raw materials generally refer to strip coils, welding wires, fluxes, etc. To ensure the quality, it must undergo strict physical and chemical inspection before investment.

(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) Process processing. Before forming, the required steel 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) Both internal welding and external welding use the American Lincoln welding machine for single wire or double wire submerged arc welding, to obtain stable welding specifications.

(8) The welded seams are all inspected by an online continuous ultrasonic automatic flaw detector, which ensures 100% non-destructive testing coverage of the spiral steel pipe. 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, each batch of three steel pipe heads shall undergo a strict first inspection system to check the mechanical properties, chemical composition, fusion condition of the weld, the surface quality of the steel pipe, and non-destructive testing to ensure the pipe making process. Only after passing the test 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 is accurately controlled.

Usually, after the above 14 steps, a spiral steel pipe has been formed, but such a spiral steel pipe cannot be directly sent to the market, and it is necessary to check the quality of the spiral steel pipe and other aspects.