Effect of parameters in flash butt welding
Flashing Feed Rate: If excessive, there is a probability of the parts freezing together without welding. If this is insufficient, intermittent flashing will occur resulting in insufficient heating in the material.
Flashing Time: If excessive, the material becomes too plastic to upset properly. If this time is less, the plasticity attained is not sufficient.
Flashing Current: If this is more than required, excessive flash is found in the weld : deep craters are formed causing pockets and inclusions in weld. If ot herwise, there is a tendency for the materials to freeze; lack of plasticity is also caused.
Upsetting Current: Too much of this parameter, causes burning or oxidation of the material even to the extent of blowing out metal. Excessive deformation also results. On the contrary, too less of upsetting current results in longitudinal cracking through weld area; inclusions and voids are not properly forced out of weld.
Upsetting Force: Excess of upsetting force causes the flow lines of the material to bend perpendicular to the welded job axis. As a consequence, poor weld results in. If upsetting force is inadequate, oxides, inclusions and voids can be found in the weld; cast metal may be retained in the weld.