Homework Number One

Due Wednesday October 14, 2015 (electronic submission through Google Drive Required)

1) The attached Word File has the stress strain curves for 6 different materials (3 copper alloys and 3 steel alloys).

· For each material determine the ductility, maximum strain, modulus, ultimate tensile strength and yield strength

· Based on these findings compare the how copper and steel are affected by elevated temperature exposure. Use the relative force required to reduce the height of a bar by 5% through open die forging as part of this comparison.

2) Explain the advantages and disadvantages of using hardness for quality control.

3) Compare the extrusion forging and deep drawing wire drawing processes. Include the mechanical properties of interest in your analysis.

4) During the sheet metal practica you made a bowl. Describe what you did using proper terminology. Would it be possible to make the same bowl using a steel alloy with an ultimate tensile strength of 50ksi and a yield strength of 30ksi? Assume the sheet was 0.010" thick and that the disk was 4.00" in diameter.

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