MSE 201 LAB II: Part a

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MSE 201 LAB II Part a

• Cold Rolling Copper Alloys

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What is Cold Rolling?

• Deformation below the recrystallization
  temperature

COLD ROLLING
HOT ROLLING
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(No Transcript)
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Lab Overview

• 4 Alloys Rolled Today
• Pure Copper
• 5 Zinc
• 10 Zinc
• 20 Zinc
• This is called Alpha Brass
• Solid solution of one phase (the alpha phase)

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Why Add Zinc?

• Zinc hardens copper by Solid Solution Hardening.

Cu Z29 Zn Z30
(click to play)
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Rolling Causes Deformation

• Deformed microstructure has many more defects,
  thus it is harder.

(click to play)
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Goal Hardness vs. CW
Increased Dislocation Density with CW
Solid Solution Hardening
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How to Measure CW?

• Percent Cold Work (CW) is the Change in
  Cross-sectional Area.

• Area of these samples Width Thickness.

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Making It Easier

• Assume width doesnt change.

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Using a Micrometer
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Using a Micrometer (cont.)Measuring to 0.001
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Using a Micrometer (cont.)The Vernier Scale
(0.0001)
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Lab Procedure

• Measure initial thickness
• Calculate target thickness values for each CW
• Measure initial width, hardness
• Roll sample to reach the target thickness
• (Set micrometer to target thickness for
  pass-thru test to save time)
• Measure Actual Thickness
• Measure hardness
• Reset micrometer and go to step 4

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Notes on Hardness Measurement

• Start with HRF scale (60kgf load)
• If reading is gt100 HRF, switch to HRB (100kgf)
• If indent is visible on the back side of the
  sample, use superficial scale
• HR30T for softer samples, or
• HR45T for harder samples
• Use spot anvil to negate curvature

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Upon Completion of Rolling

• Average hardness (HRF/HRB) and convert to DPH
• Make sure data sheet is completely filled out
• Write on your copper strip
• Alloy (Pure, 5, 10, 20)
• Class Time (125 or 325)
• Team members names
• Turn in to TA the following
• Data sheet
• Copper strip
• Micrometer

NO REPORT DUE THIS TIME, BUT LAB MEETS NEXT WEEK
TO FINISH THE EXPERIMENT!!!
NO REPORT DUE THIS TIME, BUT LAB MEETS NEXT WEEK
TO FINISH THE EXPERIMENT!!!
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Lets Roll!