The spiral tube called spiral steel tube or spiral welded pipe, the low carbon steel or low alloy structural steel strips in a helical line certain angle (called forming angle) rolled into a tube, then the tube welding seam made up, it can be used in narrow strip production of large diameter steel pipe. [Jia 13031598922 QQ2188571688] spiral pipe is mainly used for oil, natural gas transmission pipeline, its specifications with outer diameter * wall thickness. Spiral pipe has one side welding and double welding, welded pipe should ensure that the hydraulic pressure test, the tensile strength and cold bending properties of the welded joint should be in accordance with the provisions.
3 production process (1) raw material that is strip coil, welding wire, flux. Have to go through strict physical and chemical tests before they are put into the investment. (2) strip head and tail docking, using single or double wire submerged arc welding, the steel tube rolled by automatic submerged arc welding welding. (3) before molding, the strip passes through the leveling, trimming, planing, surface cleaning and conveying, and bending and handling. (4) using the electric contact pressure gauge to control the pressure of the cylinder on both sides of the conveyor, to ensure the smooth delivery of the strip. (5) the external control or internal control roll forming. (6) using the welding gap control device to ensure that the weld gap to meet the requirements of welding, pipe diameter, the wrong side of the amount and the weld gap are strictly controlled. (7) in welding and welding are used in the United States Lincoln welding machine for single or double wire submerged arc welding, thereby obtaining the stable welding specification. (8) the welding seam after welding are through the online continuous ultrasonic automatic inspection, to ensure that the spiral weld nondestructive testing coverage rate. If there are defects, automatic alarm and spraying marks, the production workers at any time to adjust the process parameters, timely elimination of defects. (9) the air plasma cutting machine to cut a single pipe. (10) into a single tube, each batch of steel pipe should be carried out strict inspection system first, chemical composition and mechanical properties of weld, inspection, blending, surface quality of steel pipe as well as a nondestructive inspection, to ensure that the process of good control, can be formally put into production. (11) in the weld on the site of continuous acoustic inspection marks, after manual ultrasound and X ray review, if there are defects, after repair, once again after the non destructive testing, until the defects have been eliminated. (12) strip butt weld and intersect with the spiral seam type joint in the tube, all through X ray TV or film examination. (13) each pipe is tested by hydrostatic pressure, and the pressure is sealed by radial seal. The test pressure and time are strictly controlled by the steel pipe water pressure computer testing device. Automatic print record of test parameters. (14) the pipe end machining, the end verticality, accurate control of slope angle and blunt edge