The heating provoked by the passage of an elevated current between the surfaces of pieces that must be joined head to head allows, if accompanied by other conditions, to obtain a valid welding.
In general must be joined the extremities of bars, spins, tubes or other manufactured with longitudinal development.
The elevated current that heating provokes and an adapted force of jam between the surfaces allow to obtain a joint with optimal mechanical characteristics.
When the surfaces to weld are constituted by thin thick or the characteristics demanded are many elevated is adopted the flash-butt welding.
In this case the heating of the surfaces to join is obtained approaching with low speed two pieces so that the contact develops progressively many sparkes that will cause the fusion.
At this point, is applied with high speed a force such to provoke the expansion of the material at high temperature and the realization of an excellent welded joint.