Tip for Problem 5

Determine how much force an extrusion machine must apply to a copper square bar (4cmx4cm) in order to make it a square bar (3cmx3cm) at 500C and 800C. Under what conditions would it be worthwhile to operate at the higher temperature? Under what conditions would it be worthwhile to operate at the lower temperature? The extrusion coeffiecients for copper are 260MPa at 500C and 100MPa at 800C

To help you prepare the answer consider the following.

• Specific numbers are only required for the calculations of force.
• Running at a higher temperature is going to require more energy and thus increase cost.
• A higher force machine will likely be more expensive to both purchase and maintain.