In railway construction, rail bending and forming process is the core technology for realizing complex curve design such as line curves and turnout areas. It is mainly divided into two types: cold bending process and hot bending process.
The cold bending process is carried out at room temperature. The rail cold bending machine applies controllable external force to the rail to slowly deform it. The equipment uses a computer control system to accurately adjust the bending angle and curvature, and the error can be controlled within a very small range. It is suitable for small radius curve rails and scenes with extremely high precision requirements, such as turnout areas in urban rail transit. This process does not change the internal organizational structure of the rail, can retain its original mechanical properties, and has low energy consumption and easy operation. However, cold bending has high requirements on the toughness of the rail material, and stress relief treatment is required after bending to avoid cracks during use.
The hot bending process requires the rail to be heated to the austenitizing temperature range of 900-1100℃ first, and after the rail is softened, the shaping is completed by the rail bending equipment. The heating method mostly uses medium frequency induction heating to ensure uniform temperature. This process is suitable for large radius curves or rails with hard materials and easy cracking during cold bending. It can reduce bending damage, but the process is complicated. After hot bending, the mechanical properties of the rails need to be restored through cooling, normalizing, tempering and other heat treatments. The cost and energy consumption are relatively high.
The two processes have their own advantages and disadvantages. In practical applications, they need to be comprehensively selected according to the track design requirements (such as curve radius, rail material), engineering costs and construction conditions. For example, high-speed rail lines have strict requirements on smoothness, and cold bending processes are often used to ensure accuracy; while for large radius curves on heavy-duty railways, hot bending processes can better take into account strength and forming effects. Accurate control of the rail bending and forming process is the key basis for ensuring the safe and smooth operation of trains. As a professional rail supplier, GNEE RAIL can provide you with the best products and services. If you need to purchase rails, please contact us.