(1) The raw material is strip coil, welding wire, flux.  They must undergo rigorous physical and chemical tests before they are put into use.  

(2) Single wire or double wire submerged arc welding is used for butt joint of strip steel head and tail, and automatic submerged arc welding is used for repair welding after rolling into steel pipe.  

(3) Before forming, strip after leveling, cutting edge, planing edge, surface cleaning transport and bending treatment.  

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

(5) External control or internal control roller 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 wrong edge and the weld gap are strictly controlled.  

(7) Lincoln welding machine of the United States is used for single wire or double wire submerged arc welding for internal and external welding, so as to obtain stable welding specifications.  

(8) All welded welds have been checked by on-line continuous ultrasonic automatic damage instrument, which ensures 100% nondestructive testing coverage of spiral welds.  If there is a defect, automatic alarm and spraying mark, production workers can adjust the process parameters at any time according to this, and eliminate the defect in time.  

(9) The air plasma cutting machine is used to cut the steel pipe into single roots.  

(10) After cutting into a single steel pipe, each batch of three steel pipe heads shall be subjected to a strict first inspection system to check the mechanical properties of the weld, chemical composition, melting status, surface quality of the steel pipe and nondestructive testing to ensure that the pipe making process is qualified before being formally put into production.  

(11) The part with continuous acoustic flaw detection mark on the weld shall be reexamined by manual ultrasonic and X-ray. If there is any defect, it shall be reinspected by non-destructive test after repair until it is confirmed that the defect has been eliminated.  

(12) The butt weld of strip steel and the tube where the D-joint intersects with the spiral weld are located shall be inspected by X-ray television or film.  

(13) Each steel pipe is subjected to hydrostatic test, and the pressure is radial sealed.  The test pressure and time are strictly controlled by the microcomputer testing device for steel pipe water pressure.  Test parameters are automatically printed and recorded.  

(14) Pipe end machining, so that the end perpendicularity, groove Angle and blunt edge can be accurately controlled.