Based on the theory of the elastoplastic distortion,using the correlative knowledge about the three roller plate bending rolls, we sdudied how to calculate the structural parameters of the bending rollers in coilbox deeply, and concluded the main points about some important structural parameters such as the roll diameter and the roll distance.

According to the operation of reducing/sizing mill, a Standard method of steup and adjustment of roll , gap line speed , roll diameter , entry sections , tension between NTM and RSM has been established , as a guide for operator to adjust reducing/sizing mill.

The result indicates that the ratio of roll diameter has the most important effect on the end curl,the angle of entrance is in the second place,the roll rotational velocity has the weakest effect.

The research indicates that the ratio of roll diameter has the most important and complex effect on the head end curl and the roll rotation speed in thick plate rolling or the entrance angle in thin plate rolling is in the s.

According to the model simulate the motor load adapting to software VB,analyze the influence to the motor load on geometry dimension about the tapes,roller diameter and the friction coefficient.