Methods of Welding Rails and Their Advantages and Disadvantages

In order to meet the needs of new seamless lines, rail welding problems arise for rail. At present, the common methods of welding rails are flash contact welding, gas pressure welding and thermite welding.

Flash contact welding

The first method is flash contact welding. This welding method is mainly used in various rail welding factories, because the welding in the factory can ensure the welding quality of the rails. When welding in the factory, the 100-meter-long rail is usually placed in a specific machine, and then heated according to the principle of the thermal effect of the current. When the rail is heated to a plastic state, it is then extruded at an extremely fast speed. The advantage is that the strength of the rail welded by this method is equivalent to that of the base metal, and the surface is smooth and easy to grind and shape. The disadvantage is that this method has certain limitations, and the rails can only be welded in the factory.

Gas pressure welding

The second is gas pressure welding, this welding method is mainly the use of acetylene gas and oxygen reaction to produce heat for rail welding, and flash welding, when the rail is heated to a plastic state, under the pre-applied pressure, the two strands of rail extrusion together, so as to weld the rail. This method is generally suitable for outdoor construction sites, due to the interference of the external environment, the welding quality is far less than flash contact welding, and this welding method is usually not used as a last resort. The advantage is convenient, suitable for outdoor work.

Thermit welding

The third welding method is thermic welding, with air pressure welding this welding method is also suitable for outdoor sites, the welding principle is the use of iron and aluminum REDOX reaction, in the oxidation process will release a lot of heat, the generated hot metal will weld the two steel rails together.

Comparison of these methods

Flash contact welding welding speed is fast, welding quality is stable, but the welding machine investment is large, the power required is also large.

Pneumatic welding one-time investment is small, no high power supply, welding time is short, welding quality is good, the disadvantage is that the welding of the joint section requirements are very strict, and in the welding requires a certain longitudinal movement of the rail, so the welding of the ultra-long rail has a certain difficulty, especially can not be cross-zone seamless line welding.

The welding method of thermite welding is relatively simple, the requirements for the operator are relatively low, the welding time is short, and the welding can be carried out in the case of fixed rail, but the welding quality is not as good as contact welding and air pressure welding.