Liaoning Yufei High Frequency Equipment Co., Ltd.

Introduction to High Frequency Welding

High frequency welding is a new welding process that uses the skin effect and adjacent effect generated by high-frequency current to connect steel plates with other metal materials. The emergence and maturity of high-frequency welding technology is a key process in the production of straight seam welded pipe (ERW). The quality of high frequency welding directly affects the overall strength, quality grade and production speed of welded pipe products.


Fundamental:

The so-called high frequency is relative to the frequency of the alternating current of 50 Hz, and generally refers to a high frequency current of 50 kHz to 400 kHz. When high-frequency currents pass through metal conductors, they produce two peculiar effects: skin effect and proximity effect. High frequency welding uses these two effects to weld steel pipes.

The skin effect means that when an alternating current of a certain frequency passes through the same conductor, the density of the current is not uniformly distributed over all sections of the conductor. It concentrates the surface of the main conductor, that is, the current density of the conductor is large on the surface of the conductor, and the density inside the conductor is small, so we call it "the skin effect". The skin effect is usually measured by the penetration depth of the current. The penetration depth value is smaller, and the skin effect is more significant. This penetration depth is proportional to the square root of the resistivity of the conductor and inversely proportional to the square root of the frequency and permeability. In layman's terms, the frequency is higher, and the current is more concentrated on the surface of the steel plate; the the frequency is lower, and the surface current is more dispersed. It must be noted that although steel is a conductor, its magnetic permeability will decrease with increasing temperature, that is, when the temperature of the steel plate rises, the magnetic permeability will decrease and the skin effect will decrease.

Proximity effect means that when a high-frequency current flows in opposite directions in two adjacent conductors, current will flow to the close edges of the two conductors. Even if the two conductors have a shorter side, the current does not follow. For shorter routes, we call this effect a "proximity effect."

The proximity effect is essentially due to the effect of inductive reactance. Inductive reactance plays a dominant role in high frequency currents. The proximity effect increases as the frequency increases and the spacing of adjacent conductors approaches. If a core is added around the adjacent conductor, the high frequency current will concentrate more on the surface of the workpiece.

These two effects are the basis for achieving high frequency welding of metals. High frequency welding uses the skin effect to concentrate the energy of the high-frequency current on the surface of the workpiece; the proximity effect is used to control the position and range of the high-frequency current flow path. The speed of the current is very fast, it can heat, melt and join the adjacent steel plate edges in a short time.
Related News
  • The Brief Introduction of RF dryer

    The Brief Introduction of RF dryer

    March 13, 2019Tieling Unify high frequency equipment co., LTD is a science and technology company which develops high frequency heating equipment. The company has gathered a number of senior and intermediate techni...view
  • Introduction of High Frequency Welding Machine

    Introduction of High Frequency Welding Machine

    July 29, 2019Unlike other welders, high frequency welding machine is not just a single weld. The high frequency welding machine can be used not only for the welding of various metal materials, but also for the pro...view
  • Technical Analysis of High Frequency Welding Machine

    Technical Analysis of High Frequency Welding Machine

    April 15, 2019High frequency welding machine is a kind of high frequency dielectric heating technology applied in the field of plastic packaging equipment.The main principle of the amount and high field of plastic ...view
  • Overview And Advantages Of Hf Machine

    Overview And Advantages Of Hf Machine

    May 24, 20191.What is hf machineHf machine: Using high frequency switching technology, frequency of hf machine is generally above 20kHz. But the endurance capacity of hf machine is poor in harsh electrical and en...view
  • The Heating Principle and Application of High Frequency Equipment

    The Heating Principle and Application of High Frequency Equipment

    October 23, 2017The high frequency equipment is not heated by heat conduction. Its heating principle is not difficult to understand, it is under the action of the high frequency electric field, and the molecules of t...view
  • How To Deal With The Faults Of Hf Welding Pvc?

    How To Deal With The Faults Of Hf Welding Pvc?

    May 24, 2019If the time of hf welding pvc is too long, there are often some faults. After the failure occurs, users must find and deal with it in the first time and solve it in time. For different faults, the sol...view
contact
©Liaoning Yufei High Frequency Equipment Co., Ltd. All RIGHTS RESERVED
sitemap Privacy Policy