An experimental investigation into the warm deep-drawing process on laminated sheets under various grain sizes

It has been proved by many researchers that increasing the temperature in warm deep-drawing process of single layer sheets decreases the forming load, however, this phenomenon is not necessarily the case in warm deep-drawing process of laminate sheet. The objective of the present paper is to carry out a comprehensive investigation on warm deep-drawing process on laminated sheets experimentally. Based on the results of this study, it can be observed that by raising the temperature, variation of forming load more depends on blank holder force (BHF). In this study, thinning and wrinkling in Al 1050/St 304 and Al 5052/St 304 samples for each layer in warm deep-drawing process are evaluated individually. In addition, the effects of various grain sizes, blank temperatures and sequence layer on forming load are investigated. In order to carry out a comprehensive survey of warm deep-drawing; three blank temperatures namely, 25 °C, 100 °C and 160 °C are examined. Furthermore, to achieve various grain sizes, the aluminum sheets are annealed at 350 °C, 400 °C and 450 °C for 1 h. Finally, several tests are conducted to obtain the influences of grain size on some material characteristics such as stress, elongation and friction coefficient. Keywords: Warm deep-drawing, Laminated sheet, Load–displacement curve, Grain size, Blank holder force