Characteristics of Aluminothermic Welding of Rails

1.Preheating

In the process of theremit welding, the preheating temperature plays a decisive role in the welding quality. Improper preheating will cause poor welding. The performance of the welding heat affected zone will deteriorate, which will lead to welding failure.

The rail thermit welding timed preheating method adopts the rail top strong preheater developed in our designing. Under the constant process parameter specification, the preheating temperature of the rail end face is controlled by time to reach more than 600 ℃. At this temperature, the rail end face will not burn completely. , but it can ensure that the temperature distribution of the rail end face is uniform during pouring.

Secondly, in the design of the welding sand mould pouring system, part of the aluminothermic molten steel is used to further heat the rail end face so that it can be adjusted to a suitable welding temperature range. Since the process parameters of the strong preheater are constant, the preheating temperature and molten steel of the rail end face is stable, as well as the welding process of the rail during welding and pouring is also constant. When parameters are stabilized and the welding quality is reliable. The welding process with timed preheating greatly reduces the influence of human factors and makes the welding quality stable and reliable.

2. One shot crucible

Using durable magnesia crucible and self-fusing plug automatic pouring technology. The use of durable magnesia crucible reduces the inclusion of silicon in the thermit weld, which improves the purity of the weld metal, it can adjust the silicon content in the weld as needed to improve the weld strength. The automatic pouring of self-fusing plugs simplifies the operation process, reduces the influence of human factors and makes the welding process more safer.

Combined with the current situation of China, we have developed an environmentally friendly disposable one shot crucible, which is characterized by no harmful gas generated during use, which effectively protects the physical and mental health of operators under harsh conditions. The use of one shot crucibles reduces factory welding tools and greatly simplifies operations, so it is widely welcomed by the project site.

3. Thermit portion(Thermit Power)

With the increase in the type of rails in China, U74 hot-rolled rails, U71 Mn hot-rolled rails, PD2 quenched rails, PD3, hot-rolled rails, PD3 waste heat quenched rails, rare earth rails and other rails have been put into use, and the types of rail thermit portion are also increasing. Recently, we has developed thermit portion suitable for different strength grades.

4. Hydraulic Shearing machine

In order to reduce the labor intensity of rail thermit welding, a two-way manual hydraulic shearing machine is developed, which is light in weight, easy to operate, safe and reliable, and greatly reduces the labor. Not only that, the use of the shearing machine avoids the joint caused by premature unpacking to ensure welding quality.

5. Rail Aligner

The developed frame type rail aligner device shorten the operation process and improve the smoothness of the joint. After the welded joint is polished and trimmed, the joint is smooth.