Introduction

• What is Casting?• The Pros & Cons of Casting• What is Forging?• The Pros & Cons of Forging• Summary• Sources to find more

information

What is What is Casting?Casting?• Forms of Casting: Investment, Sand, Forms of Casting: Investment, Sand,

PressurePressure• Casting is the procedure by which a liquid Casting is the procedure by which a liquid

metal is poured into a wheel mold or cast metal is poured into a wheel mold or cast and allowed to cool to a near final state.and allowed to cool to a near final state. Final machining is required for a finished product.Final machining is required for a finished product.

• Casting is a simple and fast method to Casting is a simple and fast method to create wheels with greater detail than create wheels with greater detail than that of other methods.that of other methods.

• Pressure casting is the best way to cast a Pressure casting is the best way to cast a wheel because it reduces void wheel because it reduces void percentage.percentage.

• Typically used for daily driving.Typically used for daily driving.

• Sand Casting

• Pressure Casting

Pros & Cons of Casting

• Low cost, $125 each• Easy to mass produce• Less material waste during production• Cannot withstand as much pressure or

frequency of impact as forged can• More impurities and voids due to the

production of wheels through a molten state

Before Track Day After Track Day

What is What is Forging?Forging?

• Starts as billet, then cut into the right length, heated to a T6 condition to get the right mix of strength and ductility, and pressed into shape undergoing 6-12000 tons of pressure.

• Forging puts energy into the metal and changes the internal grain structure (crystalline) and this change in the grain structure is what gives a forging additional strength in comparison to the original billet rod.

• “A forged aluminum wheel has a higher specific strength as well as higher toughness in comparison to a casting. This allows an engineer to design a wheel that is lighter, stiffer and less susceptible to cracking under impact and with better fatigue properties than a casting product.”1

• Elongation of grain structure with alignment of the shape of the wheel.

• Used in racing applications.

Pros & Cons of Forging

• Light weight, more economical• Higher strength, safer in applications• High cost for products, $500 each• Longer process to make than casting• Waste of excess material• The wheel on the right withstands a load of

71,200 kg before it deforms by 5 cm. The steel wheel on the left can only withstand 13,600 kg when it also deforms by 5cm. This means that the wheel on the right is 5X as strong.

Cast Steel Forged Aluminum

Summary ofCast vs. Forged• Cast is heavierCast is heavier

• Forged is stronger and has more resistance to fatigue Forged is stronger and has more resistance to fatigue and impactand impact

• In comparison to forgings, castings are made by In comparison to forgings, castings are made by pouring molten metal into a mold and have pouring molten metal into a mold and have considerably lower strength, ductility, and fatigue considerably lower strength, ductility, and fatigue resistance. Castings often suffer from defects in the resistance. Castings often suffer from defects in the form of voids or porosity. The main trait of castings form of voids or porosity. The main trait of castings are their low cost and ability to be produced in high are their low cost and ability to be produced in high volumes but at the expense of strength and weight.volumes but at the expense of strength and weight.

1.1. HRE WheelsHRE Wheelswww.hrewheels.com/technology/materials/www.hrewheels.com/technology/materials/

2.2. Motor ArchiveMotor Archive www.motoractive.com.au/wheels.htmwww.motoractive.com.au/wheels.htm

3.3. AlcoaAlcoawww.alcoa.com/alcoawheels/europe/en/benefits_forged.aspwww.alcoa.com/alcoawheels/europe/en/benefits_forged.asp

4.4. GMGMwww.gmaccessorydealer.com/wheels/forgedversuscast.aspwww.gmaccessorydealer.com/wheels/forgedversuscast.asp

5.5. GoogleGooglewww.jepsculpture.com/art/ben-casting.jpgwww.jepsculpture.com/art/ben-casting.jpg

6.6. Motor TrendMotor Trendwww.motortrend.com/f/motorsports/bmwwww.motortrend.com/f/motorsports/bmw