Abstract: According to the waviness function and the corresponding longitudinal fiber's non-homogeneous elongation of the eight main strip shape (I.e. flatness defects) in industry production, the displacement function and boundary condition of the inner stress for the buckling process which produces the waviness is abstracted. Furthermore, buckling and postbuckling models are established by use of elastic thin plate theory and the principle of energy, and numerical examples are analyzed and calculated. On the basis of the research of the strip buckling and postbuckling at normal temperature, the strip buckling at high temperature is studied , and the buckling criteria and the deforming route at variable conditions is obtained.

Key words: Buckling/postbuckling, Flatness defect, High temperature, Part width, Strip