Electrohydraulic Forming of Sheet Metal

1
Electrohydraulic Forming of Sheet Metal

• February 13, 2003
• Rachel Sharp
• Corinne Packard
• Isaac Feitler
• Hao Hu

2
Advantages of High Velocity Metalforming

• Complex pieces can be formed without using
  several different parts (seamless)
• Closer tolerances can be achieved
• Difficult to form alloys can be used
• Waste is significantly reduced

3
Experiment Setup

• Pressure Vessel
• Die
• Capacitor Bank Electronic System

4
Titanium

• Good Strength to Weight ratio
• Corrosion Resistant
• Main Uses
• Aerospace
• Marine
• Power Generation
• Offshore Industries
• Architectural
• Turbine engines

5
Titanium Alloys

• Alpha Titanium Alloys
• Lowest strength, formable, weldable
• Yield strength from 25ksi 70ksi
• Alpha/Beta Alloys
• High strength, moderate creep resistance
• Yield strength from 125ksi 175ksi
• Near Alpha Alloys
• Medium strength, high creep resistance
• Near Beta Alloys
• Meta-stable, lack ductility, low creep resistance
  
• Yield strength from 115ksi 200ksi

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High strength Titanium alloys Ti-6Al-4V ELI
Grade 23

• Ti-6Al-4V ELI
• Contains 0.13 max oxygen, improving ductility
  and fracture toughness

Mechanical Properties at 25C Density (1000
kg/m3) 4.43 Poisson's Ratio 0.34200001 Elastic
Modulus (GPa) 113.8 Tensile Strength
(Mpa) 896 Yield Strength (Mpa) 827  Elongation
() 15  Reduction in Area () 35  Hardness
(HRC) 35  Impact Strength (J) 24  Thermal
Properties between 20C and 100C Thermal
Expansion (10-6/ºC) 8.6
7
Car Mirror Casing

• Unique shape presents challenge.
• Titanium mirror casing is very marketable.
• Strength of Ti alloy might prevent inconveniences
  such as dents, etc.

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Gantt Chart
Week
1 2 3 4 5 6 7 8 9 10 11 12 13 14

Vessel design and parts acquisition
Capacitor bank acquisition (at MIT, outside of
MIT if needed)
Pressure Vessel assembly
CAD 3D printing of mold
Casting of mold
Break
Electrohydraulic test
Funnel formation
Final part formation
Presentation preparation
Pressure Vessel
Capacitor Bank
Mold
Electrohydraulic forming
Final Presentation
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Risks and Contingencies

• Relying on outside sources for key components
  such as capacitor bank.
• Large turnaround time for experiment setup
• Mirror casing shape potentially too complicated