Abstract: Repeated bending occurs toward the direction of rail head and rail base during the cooling which can lead to significant bending deformation and residual stress after cooling. The longer the rail is, the more obvious this phenomenon is. In addition to cooling function, a kind of cooling bed with a pre-bending process is used in order to solve this problem on 100m rail. The synchronous movements on this cooling bed can be realized by the automatic control system after establishing the mathematical model of bending deformation after rolling. The rail is reversely bent toward the rail base before cooling according to the pre-bending control of the pre-bending curve and is straight after cooling, which can realize the control of the residual stress after pre-bending and straightening. The straightening residual stress is significantly reduced after the pre-bending.

Key words: long rail| pre-bending| mathematical model

摘要： Repeated bending occurs toward the direction of rail head and rail base during the cooling which can lead to significant bending deformation and residual stress after cooling. The longer the rail is, the more obvious this phenomenon is. In addition to cooling function, a kind of cooling bed with a pre-bending process is used in order to solve this problem on 100m rail. The synchronous movements on this cooling bed can be realized by the automatic control system after establishing the mathematical model of bending deformation after rolling. The rail is reversely bent toward the rail base before cooling according to the pre-bending control of the pre-bending curve and is straight after cooling, which can realize the control of the residual stress after pre-bending and straightening. The straightening residual stress is significantly reduced after the pre-bending.

关键词: long rail| pre-bending| mathematical model