(1) Raw materials, i.e. strip coil, welding wire and flux. In the input before are to pass a rigorous physical and chemical examination.
 
     (2) large diameter spiral steel pipe strip head and tail butt, the choice of single or double-wire submerged arc welding, after the coil into a steel pipe, the choice of active submerged arc welding filler welding.

     (3) before forming, the strip by leveling, edge cutting, edge planing, surface finishing transport and to bend the edge of the treatment.

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

     (5) The use of external or internal control roll forming.

     (6) The use of weld gap control equipment to ensure that the weld gap to meet the welding requirements, pipe diameter, the amount of misalignment and weld gap are strictly controlled.

     (7) Both the inner and outer welding are selected from the United States Lincoln welding machine for single or double wire submerged arc welding, and then obtain stable welding quality.

     (8) The welded seam is checked by online ultrasonic active flaw meter to ensure 100% nondestructive testing coverage of the spiral weld. If there are flaws. Active alarm and spray symbols, production workers according to this at any time to adjust the parameters of the process to eliminate shortcomings in a timely manner.

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

     (10) cut into a single steel pipe, each batch of steel pipe are subject to a rigorous inspection system to check the mechanical properties of the weld, chemical composition, dissolution, surface quality of the steel pipe and through nondestructive flaw detection, to ensure that the pipe production process is qualified before officially put into production.

     (11) the weld seam with successive acoustic flaw detection symbols on the part, through manual ultrasound and X-ray review, if there are indeed shortcomings, through repair, and again through nondestructive testing, until the shortcomings have been eliminated.

     (12) strip weld seam and the location of the spiral weld intersecting the d-joint pipe, all through the X-ray television or film view.

     (13) each steel pipe through the hydrostatic test, pressure with radial seal. Experimental pressure and time are strictly controlled by the steel pipe water pressure microcomputer testing equipment. Experimental parameters are actively printed and recorded.

     (14) Pipe end mechanical processing, so that the straightness of the end face, bevel angle and blunt edge to get accurate control.