Welding head for rail welding

Abstract

This invention concerns a welding head for welding the extremities of two sections of rail and comprises two half -heads (10) aligned and sliding with regard to one another in a longitudinal direction. Each half -head comprises grip means (12, 13) to grasp a respective section of rail and two electrodes (16) suitable for contact with respective sections of rail in order to carry out a flash butt weld. The head also comprises traction actuator means (20) which extend in a longitudinal direction and are connected to the two half- heads (10) to shift the two half-headsin a longitudinal direction one towards the other, said traction actuator means (20) having a stroke suitable for allowing, during a cycle of welding two sections of rail, simultaneous regulation of rail tensions.

Description

technical field [0001] The invention relates to a welding head for rail welding by means of a flash butt welding or induction welding process. Background technique [0002] Welding heads of known type generally comprise two aligned sliding halves that can be moved by means of one or more hydraulic traction jacks. Each half-head usually consists of a frame with clamping elements, such as two lever parts, which can be activated by means of their own hydraulic jacks to grasp the two rails to be welded together the corresponding end of one of them. Furthermore, the half-heads are equipped with suitable electrodes for applying the welding current at the end of the rail. [0003] During welding, the two rail ends are heated to their melting point due to the high induction caused by the electric current, and after the initial preheating phase, the two ends are pressed together so that the so-called upsetting or forging of the joint area is not the same as the two Continuous prog...

AI Technical Summary

Problems solved by technology

But this process has a serious disadvantage: Since the metal is still in a plastic state and is under heavy tension when the end of the rail is released by the retracted clamping element for the half-head, these tensions can lead to changes in the newly welded joint, thereby lead to the formation of e.g. cracks

The process of closing the rails and adjusting the tension by thermite welding is slow, expensive and sometimes ineffective, since it is not always done at the time of welding but at a later date, during which changes in ambient climatic conditions may occur, This results in greater damage to the track and the risk of train derailment

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