Spiral steel pipe is a kind of product formed by welding technology, so in the production process for the welding process is very strict.  

(1) Raw materials are strip coil, welding wire and flux.  Strict physical and chemical tests must be carried out before being put into operation.  

(2) The joint of strip steel head and tail shall adopt single wire or double wire submerged arc welding, and automatic submerged arc welding shall be used for repair welding after the steel pipe is rolled.  

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

(4) Before forming, the strip is flattened, trimmed, planed, surface cleaned, transported and bent.  

(5) Using external control or internal control roller forming.  

(6) The weld gap control device is adopted to ensure that the weld gap meets the welding requirements, and the pipe diameter, staggered edge and weld gap are strictly controlled.  

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