Rail straightening technology is crucial in heavy rail production. It can ensure the straightness of the rails and improve the safety and stability of railway operation. Heavy rail straightening is mainly based on the principle of elastic-plastic bending. The rails will produce various bending deformations during the rolling process. During straightening, the reverse bending force is applied to the rails to make the rails produce elastic-plastic deformation, thereby offsetting the original bending deformation and achieving the purpose of straightening. Specifically, the straightening rollers of the straightening machine repeatedly bend the rails to redistribute the stress inside the rails, so that the rails gradually tend to be straight.
Hot straightening
Usually, it is carried out immediately after the hot rolling of the rails. At this time, the rail temperature is high, the plasticity is good, and it is easy to straighten. Hot straightening can effectively eliminate the thermal stress and most of the bending deformation generated by the rails during the rolling process, laying a good foundation for subsequent cold straightening. The equipment for hot straightening is generally a hot straightening machine, which has a large straightening force and a high straightening speed, and can meet the straightening requirements of high-temperature rails.
Cold straightening
The rails after hot straightening may produce new deformations during the cooling process. At the same time, some minor bending defects may not be completely eliminated during hot straightening, which requires cold straightening. Cold straightening is to accurately straighten the rails at room temperature to meet the high-precision straightness requirements of the rails. Cold straightening usually adopts methods such as pressure straightening or stretch straightening, and the equipment includes cold straightening machines, hydraulic straightening machines, etc. During the cold straightening process, the straightening force and straightening amount need to be accurately controlled to avoid excessive deformation or surface damage of the rails.