Rarely seen welding methods

High Frequency Welding

High-frequency welding uses solid resistance heat as the energy source. The welding uses the resistance heat generated by the high frequency current in the workpiece to heat the surface layer of the welded area of the workpiece to a molten or near plastic* state, followed by the application (or not) of a top forging force to achieve the bonding of the metal. It is therefore a solid phase resistance welding method. High-frequency welding can be divided into contact high-frequency welding and induction high-frequency welding according to the way in which the high-frequency current generates heat in the workpiece. In contact welding, the high frequency current is transmitted into the workpiece through mechanical contact with the workpiece. In induction high frequency welding, the high frequency current is generated in the workpiece through the coupling of the induction loop outside the workpiece. High-frequency welding is a highly specialized welding method that requires special equipment depending on the product. High productivity and welding speed up to 30m/min. are mainly used for welding of longitudinal or spiral seams in the manufacture of pipes.

Explosion welding

Explosion welding is also another solid phase welding method with chemical reaction heat as the energy source. But it is the use of explosives explosion generated by the energy to achieve the metal connection. Under the action of the explosion wave, two pieces of metal in less than a second to be accelerated impact to form a metal bond. In a variety of welding methods, explosion welding can be welded the widest range of dissimilar metal combinations. Explosion welding can be used to weld metallurgically incompatible two metals into a variety of transition joints. Explosion welding is mostly used for cladding of flat plates with a fairly large surface area, and is an efficient method for manufacturing composite plates.

Ultrasonic welding

Ultrasonic welding is also a solid-phase welding method using mechanical energy as an energy source. When ultrasonic welding is performed, the welded workpiece is under low static pressure, and the high frequency vibration from the acoustic pole can cause strong cracking friction on the joint surface and heat it to the welding temperature to form a bond. Ultrasonic welding can be used to weld between most metal materials and can achieve welding between metals, dissimilar metals and metals and non-metals. It can be applied to the repeated production of metal joints of wire, foil or thin sheet metal of 2 to 3mm or less.