Pipeline Steel Fitting Spiral Tube

Spiral steel pipe is a spiral seam steel pipe welded by automatic double-wire double-sided submerged arc welding process by strip steel coil as raw material, often warm extrusion forming. The spiral steel pipe sends the strip into the welded pipe unit, and after multiple rolls rolling, the strip is gradually rolled up to form a circular pipe blank with an open gap, and the amount of pressure down the extrusion roller is adjusted to control the weld gap at 1~3mm, and the two ends of the weld are flush1) The raw materials are strip coil, welding wire, flux. It must undergo strict physical and chemical testing before input. (2) With steel head and tail butt, using single wire or double wire submerged arc welding, after rolling into steel pipe, automatic submerged arc welding repair welding is adopted. (3) Before forming, the strip is flattened, trimmed, planed, cleaned and conveyed on the surface and treated with bending edges. (4) The electric contact pressure gauge is used to control the pressure of the cylinder on both sides of the conveyor to ensure the smooth transportation of the strip. (5) Adopt external control or internal control roll forming. (6) 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. (7) Internal welding and external welding are made of single wire or double wire submerged arc welding using the American Lincoln electric welding machine, so as to obtain stable welding quality. (8) The welded seams are inspected by online continuous ultrasonic automatic injury instrument, which ensures 100% non-destructive 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 to eliminate the defect in time. (9) Use air plasma cutting machine to cut the steel pipe into a single piece. (10) After cutting into a single steel pipe, each batch of steel pipe must undergo a strict first inspection system to check the mechanical properties, chemical composition, fusion status, surface quality of the steel pipe and non-destructive testing to ensure that the pipe making process is qualified before it can be officially put into production. (11) The part marked with continuous acoustic flaw detection on the weld is reviewed by manual ultrasonic and X-ray, and if there is a defect, after repair, it will undergo non-destructive inspection again until it is confirmed that the defect has been eliminated. (12) The pipe where the strip butt weld and the D-joint intersecting with the spiral weld are all inspected by X-ray television or filming. (13) Each steel pipe has passed hydrostatic test, and the pressure adopts radial seal. The test pressure and time are strictly controlled by the steel pipe hydraulic microcomputer detection device. Automatic printing of test parameters. (14) Pipe end machining to accurately control the verticality of the end face, groove angle and blunt edge. Weld treatment 1. If the gap is too large, it will cause the proximity effect to be reduced, the eddy current heat is insufficient, and the weld crystal is indirectly closed and not fused or cracked. 2. If the gap is too small, the adjacent effect will increase, the welding heat is too large, and the weld will be burned; Or the weld is extruded and rolled to form a deep pit, which affects the surface quality of the weld. After heating the two edges of the pipe blank to the welding temperature, under the extrusion of the extrusion roller, a common metal grain is formed to penetrate and crystallize each other, and finally form a firm weld. If the extrusion force of the spiral steel pipe is too small, the number of common crystals formed will be small, the strength of the weld metal will decrease, and cracking will occur after the force; If the extrusion force is too large, the molten metal will be extruded into the weld, which not only reduces the strength of the weld, but also produces a large number of internal and external burrs, and even causes defects such as welding overlaps.                                                                                                                                                       Product NameSpiral tubeFabrication StandardAPI 5L/5CT ASTM A53 A252 A500  EN10217 EN10219 Material GradeGR. A/B x42 x52 x65  GR.2 GR.3 S235 S355Out DiameterDN5 - DN2500Wall Thickness3mm - 50mmLength max 75 MtrSurfacebare or with coatingCoatingFBE, 3LPP, 3LPE, Epoxy, Coal Tar ExpoxyPackageby piece or in bundlesMinimum Order Quantity5 TonsEZS Advantage1.regular sizes in stock over 2000 tons for immediate delivery2.small quantity with factory rate3.quality certificate as per EN10204 3.1b issued by manufacturer4.expert technical and export/import document consultant and support5. on-time response by email, skype, website and online messagQ: Are you a trading company or