Spiral steel pipes for water transmission pipelines are made by winding low-carbon carbon steel or low-alloy structural steel steel strips into tube blanks at a certain helix angle, and then welding the tube seams. It can use narrower strips of steel. Consumption of large diameter steel pipes. The Spiral Welded Tubes are circularly deformed and directly converted into squares. In the forming method, roll forming and roll forming are divided.
Their main difference is in the pre-molding stage, with little difference in the following consumption processes. Roll forming is a conventional molding process, which stops the cold roll forming by stopping a series of matching roll type designs on the roll during the pre-forming stage, and then calibrating. Spiral steel pipes for water transmission pipelines have simple processes, high consumption efficiency, low cost, and rapid development.
The strength of the spiral welded pipe is generally higher than that of the lsaw steel pipe, and a narrower billet can be used to consume a larger diameter pipe, and a billet having a different diameter can also be consumed with a billet having the same width. Spiral welded pipes are mainly used for oil and natural gas pipelines, and their specifications are expressed in terms of outer diameter* wall thickness. Ordinary weld forming coefficient is controlled at 1.3-1.5, thick-walled welded pipe value, thin wall to take a small value.
The elements for producing air holes in the spiral steel pipe welds for water transmission pipelines are: moisture, dirt, scale and iron filings in the flux, welding composition and masking thickness, appearance quality of the steel plate, and treatment of the steel plate side plates, welding process and steel pipe forming Spiral welded tubes, such as crafts, have single-sided and double-sided welds. Welded tubes should ensure that the hydrostatic test, the tensile strength of the weld, and the cold-bending performance are in accordance with the rules. The forming coefficient of the weld is too small, the shape of the weld is narrow and deep, gas and inclusions do not float easily, and it is easy to form pores and slag.
Spiral steel pipe welding method for submerged arc welding of the water transmission pipeline; molding process, forward pendulum intermittent production; unit speed, welding speed, unit from the decoiling machine, straightening machine, centering device, hydraulic shearing, milling machine, disc Shears, edge milling machines, board surface cleaning equipment, conveyors, board edge pre-bending equipment, forming machines, internal welds, external welds, burrs, dial-outs, slag lagging, repair welding, flat chamfering, hydraulic inspection, finished products Inspection, degreasing collection composition.
The whole process of ssaw steel pipe is as follows: Spiral steel pipe – the principle of submerged arc welding: Submerged arc welding is the use of arc heat energy welding, and manual welding rod arc welding is different: submerged arc welding of the welding wire is exposed, there is no Paint, submerged arc welding is indeed pre-paste in the place to be welded, submerged arc welding wire into the flux, the arc is burning under the flux. When the welding wire touches the workpiece and the start button is pressed, the welding wire and the workpiece are energized. The welding wire is drawn back, the arc is ignited, the welding carriage advances, and the welding wire is continuously conveyed downwards, keeping the arc burning under the flux layer under the arc. Form weld pool.