Straight seam steel pipe is a steel pipe with welds parallel to the longitudinal direction of the steel pipe. It is usually divided into metric electric welded steel pipe, electric welded thin-walled pipe, transformer cooling oil pipe, and so on.
Production Process
Straight seam high-frequency welded steel pipe has the characteristics of a relatively simple process and rapid continuous production and is widely used in civil construction, petrochemical, light industry, and other departments. It is mostly used to transport low-pressure fluid or make various engineering components and light industrial products.
1. Production process of straight seam high frequency welded steel pipe.
The straight seam welded steel pipe is made by rolling a certain specification of long steel strip into a round pipe through a high-frequency welding unit and welding the straight seam into a steel pipe. The shape of the steel pipe can be round, square, or irregular, depending on the sizing and rolling after welding. The main materials of welded steel pipes are low carbon steel and low alloy steel or other steel with σs≤300N/mm2 and σs≤500N/mm2. The production process of high frequency welding of straight seam steel pipe.
2. High-frequency welding.
High-frequency welding is based on the principle of electromagnetic induction and the skin effect, proximity effect, and eddy current thermal effect of AC charges in the conductor, so that the steel at the edge of the weld is locally heated to a molten state, and the butt weld is extruded by a roller to achieve crystal indirect Together, to achieve the purpose of welding seam welding. High-frequency welding is a kind of induction welding (or pressure contact welding). It does not need weld filler, no welding spatter, narrow welding heat-affected zone, beautiful welding shape, and good welding mechanical properties. Therefore, it is favored in the production of steel pipes. Wide range of applications.
The high-frequency welding of steel pipes uses the skin effect and proximity effect of alternating current. After the steel (strip steel) is rolled and formed, a circular tube blank with a broken section is formed, which rotates a circle near the center of the induction coil in the tube blank. Or a group of resistors (magnetic rods), the resistor, and the opening of the tube blank form an electromagnetic induction loop. Under the action of the skin effect and the proximity effect, the edge of the tube blank opening produces a strong and concentrated thermal effect, making the edge of the weld seam Rapidly heated to the temperature required for welding and squeezed by the pressure roller, the metal in the molten state realizes intergranular bonding, and forms a firm butt weld after cooling.
3. High frequency welded pipe unit.
The high-frequency welding process of straight seam steel pipe is completed in the high-frequency welded pipe unit. The high-frequency welded pipe unit is usually composed of rolling forming, high-frequency welding, extrusion, cooling, sizing, flying saw cutting, and other components. The front end of the unit is equipped with a material storage looper, and the rear end of the unit is equipped with a steel pipe turning frame; The electrical part is mainly composed of a high frequency generator, DC excitation generator, and instrument automatic control device.
Post time: Aug-09-2023