Flash-butt Welds are welds made using an electric flash butt system. The rail ends are heated using electric
flashes and then forged together using high pressure, thus fusing them. These welds are made either in railroad or
contracted rail welding plants or by an on site in-track welder.
• Flash-butt weld defects usually start with an inclusion, a lack of fusion or stress riser. The appearance
can be similar to that of a transverse fissure in the head of the rail.
Gas Pressure Welds use a similar process except that the rail ends are heated using a flammable gas and oxygen
mixture instead of electric flashes.
• Gas Pressure weld defects can occur from inclusions, lack of fusion or stress risers as with flash-butt
welds, The most significant difference is that this process does not flash parent metal off the rail ends
during welding. Prior to welding, proper alignment of ends and cleaning the ends is critical. Failure to do
so could result in the entrapment of inclusions or poor fusion during the forging processes (lamination
defects)