ME383 Modern Manufacturing Practices

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ME 383Modern Manufacturing Practices
Lecture Note 5 Rolling Dr. Y.B. Guo Mechanical
Engineering The University of Alabama
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Todays Lecture

• Typical Products by Rolling
• Mechanics of Rolling
• Quality of Rolled Parts

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Typical Products by Rolling

• Rolling Process
• Compressive deformation
• Reduced thickness by rolls

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Typical Products by Rolling

• Typical Products

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Typical Products by Rolling

• Typical Products

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Mechanics of Rolling

• Plates gt 6 mm
• Sheets lt 6 mm
• Foil 0.008 mm
• Cold Rolling at room temp.
• Hot Rolling at elevated temp.

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Mechanics of Rolling

• Neutral Point
• The location where
• To the left,
• To the right,

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Mechanics of Rolling

• Frictional Force
• Friction direction
• Draft

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Mechanics of Rolling

• True Strain
• Average Flow Stress

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Mechanics of Rolling

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Mechanics of Rolling

• Contact Length

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Mechanics of Rolling

• Force
• Torque
• Power

s
w
L
A
B
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Mechanics of Rolling

• Example

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Quality of Rolled Parts

• Wrought Structure
• Hot rolling ? fine grains

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Quality of Rolled Parts

• Defects wavy edges, zipper, edge cracks,
  alligatoring

Wavy edges due to non-uniform elongation
edge cracks due to poor ductility
Alligatoring due to impurities
Zipper due to poor ductility
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Quality of Rolled Parts

• Residual Stresses

Large roller
Small roller
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End

• Questions ?