Upper-bound modelization of an ironed three-layered polymer-coated steel strip

Global beverage can and food container consumption is very high, with billions of cans produced annually worldwide. There are several steps in can manufacturing, but ironing is the most crucial. In a previous work (Sellés et al., J Mater Process Technol 202:7–14, 2008), a series of ironing experiments were reported using a new material and an ironing simulator. This material was a three-layered polymer-coated steel, and it was seen that under some process conditions, it survived the ironing process with no damage in any of the three layers. The critical die angle was determined as well as specimen quality surface tests. In this paper, an associated theoretical ironing model is described, using the upper-bound theorem and considering the cases of successful ironing or shaving. It is possible to give insight into how to design a material that irons well. For example, the optimal layer thicknesses are also found.