Rectangular/ Square hollow section production process
(1) The raw materials are strip steel coils, welding wires, and fluxes. They must pass strict physical and chemical inspections before investing.
(2) Butt joint of strip steel head and tail, select single wire or double wire submerged arc welding, after coiling into square tube, select automatic submerged arc welding repair welding.
(3) Before forming, the strip is flattened, trimmed, planed, and the surface is cleaned, transported, and pre-curved.
(4) The electric contact pressure gauge is used to control the pressure of the cylinder at both ends of the conveyor to ensure the smooth transportation of the strip.
(5) Use external control or internal control roll forming. Carbon steel flange
(6) The welding gap control equipment is selected to ensure that the weld gap meets the welding requirements, and the pipe diameter, the amount of misalignment and the weld gap are all strictly controlled.
(7) Both internal welding and external welding use American Lincoln electric welding machines for single-wire or double-wire submerged arc welding, so as to obtain stable welding standards.
(8) The welds after welding are all inspected by the on-line continuous ultrasonic automatic flaw tester, which guarantees 100% non-destructive testing coverage of spiral welds. If there are shortcomings, it will automatically alarm and spray symbols, and the production workers can adjust the process parameters at any time according to this to eliminate the shortcomings in time.
(9) Use an air plasma cutting machine to cut the square tube into individual pieces.
(10) After cutting into a single square tube, each batch of three square tube heads shall be subject to strict initial inspection criteria to check the mechanical properties, chemical composition, fusion situation of the weld, the appearance quality of the square tube and pass the non-destructive inspection inspection to ensure that Only after the pipe-making process is qualified can it be officially put into production.
(11) Where there are successive sonic flaw detection symbols on the weld, it shall be re-examined by manual ultrasonic and X-ray. If there are defects, after the repair is passed, the non-destructive inspection shall be passed again until the defects have been eliminated.
(12) The Rectangular/ Square hollow section where the strip butt welds and the D-shaped joints intersecting the spiral welds are all inspected by X-ray television or filming.
(13) Each Rectangular/ square tube has passed the hydrostatic pressure test, and the pressure is radially sealed. The experimental pressure and time are strictly controlled by the square tube water pressure microcomputer testing equipment. Automatic printing records of experiment parameters.
(14) The Rectangular/ Square hollow section end is machined, so that the straightness of the end face, the bevel angle and the obtuse edge can be accurately controlled.