Longitudinal seam high frequency welding greenhouse pipe has the characteristics of relatively simple technology, rapid and continuous consumption, and is widely used in civil construction, petrochemical, light industry and other departments. It is mainly used to deliver low-pressure fluid or make various engineering components and light industrial products.
1. Consumption process of straight seam high frequency welding greenhouse pipe
Longitudinal welded greenhouse pipe is a kind of greenhouse pipe, which is made of long strip steel strip of certain specification coiled into circular pipe by high frequency welding machine. The shape of greenhouse pipe can be round or square or irregular, which depends on the sizing rolling after welding. The data of welded greenhouse pipes are mainly low carbon steel and low alloy steel with_s < 300N/mm2, _s < 500N/mm2 or other steels. The consumption process of high frequency welding of galvanized square pipe steel is as follows:
2. High Frequency Welding
High frequency welding is based on the principle of electromagnetic induction and skin effect, proximity effect and eddy current heat effect of alternating current charge in conductor, so that the steel part of the weld edge is heated to the melting state, and through the extrusion of rollers, the butt weld can complete the crystal indirect joint, so as to achieve the purpose of weld welding. High frequency welding is a kind of induction welding (or pressure contact welding), which does not need filler, no welding spatter, narrow welding heat affected zone, beautiful welding shape, good welding mechanical properties, etc. It is widely used in the consumption of greenhouse pipes.
The high frequency welding of greenhouse pipe is based on the skin effect and proximity effect of AC. After rolling forming, steel (strip steel) forms a circular tube blank with broken cross section. In the tube blank, one or a group of impedance (magnetic rods) rotates to the left near the center of induction coil. The impedance and the starting point of the tube blank form an electromagnetic induction circuit, under the skin effect and proximity effect. The edge of the billet teeth produces a strong and concentrated thermal effect, which makes the edge of the weld rapidly heated to the required temperature for welding. After extrusion by pressure roll, the molten metal completes the crystallization indirect bonding and forms a strong butt weld after cooling.
3. High Frequency Welded Pipe Unit
The high frequency welding process of galvanized square pipe steel is completed in the high frequency welding pipe set. 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 storage loopers, and the back end of the unit is equipped with a greenhouse pipe overturning frame. The electrical part mainly consists of high-frequency generator, DC excitation generator and automatic instrument installation. The main technical parameters are as follows:
3.1 Waste Welded Pipe
Outer diameter of circular pipe: 111~165mm
Hot-dip galvanized rectangular tube: 50 *50~125 *125 mm
Rectangular tube: 90 *50~160 *60~180 *80mm
Wall Thickness of Waste Product Tube: 2-6 mm
3.2 成型速度： 20~70米/分钟
3.2 Molding speed: 20-70 m/min
3.3 High Frequency Inductors:
Thermal power: 600KW
Output frequency: 200-250KHz
电源： 三相380V 50Hz
Power supply: three-phase 380V 50Hz
Cooling: water cooling
Encouraging Voltage: 750-1500V
4. High Frequency Encouragement Circuit
High-frequency excitation circuit (also known as high-frequency oscillation circuit) is composed of large electronic tubes and oscillation grooves installed in high-frequency attackers. It uses the amplification function of electronic tubes to activate the output signal of the anode to the grid when the tube is connected to the filament and the anode, thus forming a self-excited oscillation circuit. The magnitude of the excitation frequency depends on the electrical parameters (voltage, current, capacitance and inductance) of the oscillating groove.