(1) Raw materials are strip steel coil, welding wire and flux. Strict physical and chemical tests shall be conducted before input.
(2) The head and tail butt joint of strip steel shall be welded by single or double wire submerged arc welding, and the square tube machine shall be repaired by automatic submerged arc welding after being rolled into square tubes.
(3) Before forming, the strip steel is leveled, trimmed, planed, cleaned, transported and pre-bent.
(4) The electric contact pressure gauge is used to control the pressure of the down cylinder on both sides of the conveyor to ensure the smooth delivery of the strip steel.
(5) External control or internal control roll forming is adopted.
(6) The weld gap control device is used to ensure that the weld gap meets the welding requirements, and the pipe diameter, misalignment and weld gap are strictly controlled.
(7) For internal and external welding, Lincoln Electric Welding Machine of the United States is used for single wire or double wire submerged arc welding to obtain stable welding specifications.
(8) The welded welds have been inspected by online continuous ultrasonic automatic flaw detector, ensuring 100% of the nondestructive testing coverage of spiral welds. If there is a defect, it will automatically alarm and spray the mark, and the production workers will adjust the process parameters at any time according to this to eliminate the defect in time.
