Abstract: A brand-new explanation about the transverse buckling mechanism of strip in high temperature state on the continuous annealing production line (CAPL) is put forward—the traditional viewpoint that the transverse difference of temperature results in the buckling is incorrect, the main reason for the strip buckling is that the local tension converges toward the central width of strip results in the non-uniform tensile deformation, this resembles the wrinkling deformation in press forming. At the same time, the mechanics laws in the process of buckling are revealed by the analytical and finite element method. By using YBT test method for reference, the correctness of the analytical method and numerical calculation model is validated by uneven tensile test of sheet metal in cold state. The research brings forward a series of countermeasures to restrain the “heat buckling” of strip in the annealing furnace, and the application of which in the 2# CAPL of Bao Steel has achieved full success.

Key words: Analytical method, Buckling, Continuous annealing, Critical stress, Finite element method, Strip