Abstract: Against the ribbing problem that it is easy to produce additional shape wave and degraded product on the surface of stripe after the uncoil on the process of curl, and on the base of quantities of the field experiment and the research of theory, a set of judgment standard about the theory of big and small local shape wave is put forward combining with the relevant characteristics of small local shape wave and big local shape wave. At the same time, the problems that include the origin of axial force caused by big local shape wave on the process of ribbing, the calculation of critical bucking stress and axial force in the zone of ribbing are analysed systemic. After that, against the two different conditions of small local shape wave and big local shape wave, the two corresponding math- ematic models about the calculation of ribbing value are set up. After the ribbing value in the different conditions are simulated quantitatively and compared with field data, the statistic ind- icate that the deviation value of model data with field data is within ten percents and the maximal deviation value in one time is within fifteen percents, which reach relatively high accuracy and meet the requiremet for prediction accuracy of ribbing value on the project. It also bring forward the convincing theoretical basis for the ribbing cure of the factory and creates vast economic returns.

Key words: Cold rolling, Local shape wave, Ribbing