Defects identification of high frequency inductive welding

Abstract

High frequency inductive welding has been the subject of many researches, both in theoretical and practical sense, for around fifty years. The idea of having the inductor being supplied by high frequency currencies has been practically realized in a way that formed steel tube is put into an inductor, where, inside the tube, impeder, as a field concentrator, is being located. Mainly ferrite materials are used as impeders for this particular field of frequencies. The development took the direction of improvement of the ferrite quality so that energetic savings could be achieved. The theory contributed to the description of the electromagnetic theory of these phenomena which ended with the calculation of the heat distribution within the zone of the steel tube weld. The authors of this paper have been demanding, through their long-term researches, the attitudes of the current world theory that the distribution of the heat within the zone of the weld is the only one which can affect the quality of the weld. The authors have researched and found out that HF welding by applying the ferrite impeder disturbs chemical and mechanical characteristics of the weld and of the whole steel tube up to the extent that these are quite different from the entering steel stripe, so this is the way to point to the disadvantage of the so far applied welding theory in the world.

Keywords

• index terms--generator
• welding
• impeder
• frequency
• defect
• weld
• atomic reaction
• hardness
• chemical composition