One: Physical and chemical inspection of raw materials such as strip coils, welding wires, and fluxes. Large-caliber water supply pipe

Two: The strip head and tail are butt jointed by single-wire or double-wire submerged arc welding, and automatic submerged arc welding is used for repair welding after coiling into a steel pipe.

Three: Before forming, the strip undergoes leveling, edge trimming, edge planing, surface cleaning and conveying, and pre-bending treatment.

Four: 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.

Five: adopt external control or internal control roll forming.

Six: 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.

Seven: Both internal welding and external welding adopt American Lincoln electric welding machine for single-wire or double-wire submerged arc welding, so as to obtain stable welding quality.