Arc Furnace Melting and Sand Casting of Aluminum and

CopperJames BonnellJames O’Brien

Engr 45Dec 8, 2004

Arc Furnace Typical Uses

• Metal Recycling• Used to reclaim iron, nickel and cobalt alloy• Scrap is generally 100% of the charge• With computer control is used to separate

various mixed scrap to specific compositions

Arc Furnace

Benefits:• Cost per ton of final product is less

(taking into account all expendables)

• Can melt almost any type of metallic scrap• Good for smaller production runs requiring

less capacity.

Source: http://tristate.apogee.net/et/

Power Consumption

Energy Required to Produce One Ton of Liquid Steel

0

2

4

6

8

10

12

14

16

18

20

Arc Furnace Oxygen FurnaceProcess

Mill

ion

Btu

Source: http://tristate.apogee.net/et/

Cost Per Ton of SteelMaterial Cost per Ton of Produced

Steel

0

20

40

60

80

100

120

140

Arc Furnace Blast FurnaceProcess

Dol

lars

per

Ton

Source: http://tristate.apogee.net/et/

Basic Electric Arc Furnace

DC Electric Arc Furnace

www.jfe-21st-cf.or.jp

Current Carrying Capacity

Source: www.foundrytraders.com

Nominal Diameter Electrode Type

mm inch Regular Power High Power Ultra High Power

75 3 1,000 ~ 1,400    100 4 1,500 ~ 2,400    150 6 3,000 ~ 4,500    200 8 5,000 ~ 6,900 5,400 ~ 9,000  250 10 7,000 ~ 10,000 8,000 ~ 12,000  300 12 10,000 ~ 13,000 13,000 ~ 17,400 18,000 ~ 22,000

350 14 13,500 ~ 18,000 17,400 ~ 24,000 20,000 ~ 30,000

400 16 18,000 ~ 23,500 21,000 ~ 31,000 25,000 ~ 40,000

450 18 22,000 ~ 27,000 25,000 ~ 40,000 32,000 ~ 45,000

500 20 25,000 ~ 32,000 30,000 ~ 48,000 38,000 ~ 55,000

 

Our Arc Furnace

• Started as a standard arc lamp used for exposing photographic emulsions.

Modified Arc Lamp

• Moved the bottom electrode to be parallel with the top electrode

• Added:• Platform• Crucible

Attempted Arc Start with Steel

Arc Start with Carbon Rod

Sand Casting Mold and Products

www.simmons.comwww.birt1.demon.co.uk

Sand Casting Suitability

Advantages:Least Expensive Casting

ProcessCastings can be up to Several

TonsLess Expensive than

Machining Shapes from Bar Stock

Can Cast Intricate ShapesCan be Used with Most

Pourable Metals and Alloys

Disadvantages:Can Only Cast Basic Part Shape

Castings Require Secondary Machining

Rough Surface Finish

www.casting-source.com

Casting Sand Types

• Basic casting sand consists of bentonite clay and sand (usually 120 grit)

• Chromite sand: a high quality refractory molding sand,with high chilling effect and stability

• Zircon sand: particularly suitable for higher melting point alloys

Source: http://www.foundrytraders.com

Basic Tools

Shrinkage Consideration

Shrinkage Rate for Small Castings

Iron - 1/8" per foot

Steel - 1/4" per foot

Aluminum - 5/32" per foot

Brass - 3/16" per foot

www.casting-source.com

General Setup

www.lethbridgeironworks.com

Our setup and mold

Disappointing Results

• Insufficient input heat to maintain molten state

• Worked to melt small samples

• Crucible broke from thermal shock when the sample melted

Final Castings

• Used Oxyacetylene Torch to heat steel crucible that would not suffer thermal shock.

• Cast aluminum and copper alloys (not quite enough heat input for copper)

Original