Effect of mechanical properties on wrinkling limit diagrams for Aluminum 5086 alloy annealed at different temperature

Abstract

This article deals with the wrinkling limit diagrams for Aluminium 5086 alloy sheets having thickness of 2.00 mm annealed at three different temperatures namely 200, 250 and 300 °C. The study pertains to deep drawing into cylindrical cups through conical die using a flat bottom punch. When a conical die is employed, the need for a hold down or clamping ring is eliminated. However, this enhances the propensity of the blank to fail by wrinkling or buckling, particularly in the early stages of a drawing process in which thin sheet blanks are used. It is proved by these researchers and others that the onset of wrinkling takes place when the ratio of strain increments (der/deθ) or the ratio of strain (er/eθ) reaches a critical value during the drawing process. These values which could be determined experimentally over which the wrinkling takes place has been shown in the form of wrinkling limit diagrams for the above grade at different annealed temperatures. An attempt is also made to develop the wrinkling theory that predicts the wrinkling based on results obtained in the form of wrinkling limit diagrams established for the above grade at different annealed temperatures. Further it was observed that the annealed sheets having high n-value, high R-value and high UTS/σy ratio improve the resistance against wrinkling.