The production technology of high-frequency welding pipe machines mainly depends on the diversity of products. A series of processes from raw materials to finished products are required. In order to complete these processes, various mechanical equipment and welding, electrical control, and inspection devices are required. These equipment and devices are arranged reasonably according to different process requirements. Typical processes for high-frequency welded pipes include longitudinal shearing, uncoiling, strip steel leveling, head and tail shearing, strip steel butt welding, loop storage, forming, welding, deburring, fixed length, flaw detection, flying shear, initial inspection, steel pipe straightening, pipe section processing, hydraulic testing, crack detection, printing coating, and finished product.
When the high-frequency welding machine determines the oscillator, inductance, and impedance, the efficiency of the oscillation tube box, output transformer, and inductance will be determined. The change in input power is roughly proportional to the change in input heat. If the input heat is insufficient, the heating edge cannot reach the welding temperature, and the solid structure is maintained without welding, forming welding cracks; If the input heat is large, the heating edge is prone to overheating when it exceeds the welding temperature, and even if it overheats, cracks will appear after stress; When the input heat is too high, the welding temperature is too high, which can cause the weld seam to crack, causing molten metal to splash and form holes. The welding temperature is generally 1350-1400 ℃.
The welding pressure of a high-frequency pipe welding machine is one of the main parameters during the welding process. After heating both sides of the pipe to the welding temperature, ordinary metal grains are formed under the action of extrusion pressure, which is mutual crystallization welding. Welding pressure affects the strength and toughness of welds. If the applied welding pressure is low, the welding edge of the metal cannot be fully compressed, and the residual non-metallic inclusions and metal oxides in the weld are difficult to discharge due to low pressure, resulting in a decrease in weld strength and easy cracking of the weld after being subjected to force; When the pressure is too high, most of the metal that reaches the welding temperature is squeezed, which not only reduces the welding strength, but also produces defects such as excessive internal and external burrs or overlap welding. Therefore, in practical applications, reasonable welding pressure should be obtained based on different varieties and specifications. According to practical experience, the unit welding pressure is generally 20~40mpa.
Due to the possible tolerances on the width and thickness of the tube blank, as well as the fluctuations in the increase of welding working temperature and welding development speed, there may not be any changes in different welding extrusion pressures involved. The amount of welding extrusion can usually be controlled by continuously adjusting the distance between the enterprise extrusion rollers or controlling the difference in circumference between the front and rear tubes of the extrusion rollers.
