Features of high frequency welded pipe mill

The high-frequency welded pipe machine develops fast through welding, the heat-affected zone of welding is small, and there is no need to clean and workpiece during welding, which can improve the welding of thin-walled pipes and metal pipes.

The production technology of high-frequency pipe welding machine 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 reasonably arranged according to different process requirements. The typical process of high-frequency welded pipes: Longitudinal shearing-uncoiling-strip leveling-head and tail shearing-strip butt welding-loop storage-forming-welding-deburring-setting Long-flaw detection-flying shear-initial inspection-steel pipe straightening-pipe section processing-hydraulic test-crack detection-print coating-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 side cannot reach the welding temperature, and maintain a solid structure without welding, forming welding cracks; if the input heat is large, the heating side is easy to overheat when it exceeds the welding temperature, and even if it is overheated, cracks will appear after stress; when When the input heat is too large, the welding temperature is too high, which will lead to cracking of the weld seam and the formation of holes due to molten metal splashing. The welding temperature is generally 1350-1400 °C.

The welding pressure of the high-frequency pipe welding machine is one of the main parameters in the welding process. After the two sides of the pipe are heated to the welding temperature, ordinary metal grains are formed under the action of extrusion force, that is, mutual crystallization welding. Welding pressure affects the strength and toughness of the weld. If the applied welding pressure is small, the welding edge of the metal cannot be completely compressed, and the non-metallic inclusions and metal oxides remaining in the weld are not easy to discharge due to low pressure, the strength of the weld decreases, and the weld is easy to crack after being stressed; When it is 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 lap welding. Therefore, in practical applications, reasonable welding pressure should be obtained according to different varieties and specifications. According to practical experience, the unit welding pressure is generally 20 ~ 40mpa.

Due to possible tolerances in the width and thickness of the tube blank, as well as fluctuations in increasing welding working temperature and welding development speed, there may be no variation involving different welding extrusion forces. The amount of welding extrusion can usually be controlled by continuously adjusting the distance between the extrusion rollers of the enterprise or controlling and studying the circumference difference between the front and rear pipes of the extrusion rollers.