What is the principle of affecting the quality of high frequency welded pipe operation

Before the application of high-frequency welded pipes, deamination work should be done with oxygen scavenger. In this way, the total number and specifications of high-frequency welded pipe residues during operation will be reduced. High-frequency welding is to directly weld some specifications of steel strips into The compressive strength and section shrinkage of seamless steel pipes and high-frequency welded pipes can be calculated by formulas. In addition, the cross-sections of seamless steel pipes for different purposes are also different. The mechanical properties of straight seam steel pipes determine the choice of steel.

What is the principle of affecting the quality of high-frequency welded pipe operation?
When heat is input, the welding current (or welding temperature) is one of the main parameters of the welding process, which is difficult to measure, so the heat input is used instead. When the oscillator, inductance, and impedance are determined, the energy storage circuit and output transformer are determined. Efficiency, the change in input power is roughly proportional to the change in input heat.
When the input heat is insufficient, the heated edge does not reach the welding temperature, and still maintains a solid structure and cannot be welded, forming welding cracks; when the input heat is large, the heated edge is higher than the welding temperature, easy to overheat or even burn, and crack after being stressed ;When the input heat is too large, the welding temperature is too high, causing the weld to break, causing molten metal to splash and form holes. The melting welding temperature is generally 1350 ~ 1400. According to practical experience, the unit welding pressure of high frequency welded pipe is generally 20~ 40MPa.

Due to the possible tolerance of the width and thickness of the tube blank and the fluctuation of welding temperature and welding speed, it may involve the change of welding extrusion force. The amount of welding extrusion can be controlled by adjusting the distance between the extrusion rollers, and the welding speed can also be controlled by The circumference difference between the front and rear tubes of the squeeze roller is controlled.
In the high-frequency welded pipe, the welding quality increases with the welding speed. Due to the shortening of the heating time, the width of the edge heating zone is narrowed, and the time for forming metal oxides is shortened. If the welding speed is reduced, not only the heating zone becomes wider , and the width of the melting zone also changes with the input heat, resulting in larger internal burrs. When welding at low speed, the input heat is less, and welding is difficult. The high-frequency welded pipe does not meet the specified value and is prone to defects. Therefore, welding high-frequency pipes When welding, the welding speed should be selected according to different specifications and varieties under the allowable speed of the mechanical equipment of the unit and the welding device.