Foundries & Forges
Foundries and forges are facilities which manufacture whole metal parts. Often used to manufacture the same types of parts, such as automotive crankshafts, forges and foundries use very different processes, each with its own benefits and drawbacks. A foundry is a facility which manufactures metal castings, a process which uses a closed mold (or die) to shape molten metal into specific, mid to high tolerance parts. Forges, or smithies, use hot and cold hammering and stamping processes to shape metal pieces that are still in solid form. Because the products fabricated by casting and forging are often similar, the term “foundry” is often used to refer to a facility that manufactures forgings, which is a misnomer; foundries manufacture castings, and forges (also called “smithies") manufacture forgings.
Castings and Forgings Resources
Information on Casting and Forging
Image Provided by Weldaloy Products Company
Image Provided by Anderson Shumaker Company
Image Provided by Ajax Rolled Ring And Machine, Inc.
The casting process may be performed on virtually any type of metal or alloy and is typically preferred for shaping aluminum, brass, silver, copper and zinc alloys.
- Casting Methods
- Grey Iron Casting – produces cost-effective cast iron parts for non-critical applications.
- Die Casting – uses precision steel molds and high pressure injection to form complex metal parts.
- Investment Casting ( Casting) – forms high precision, high performance alloys with high accuracy and repeatability in wax-plastic-mercury composite molds.
Forging is the preferred process for manufacturing high-strength steel, copper, magnesium, nickel, aluminum, titanium and related alloy parts. Metalworking processes such as hot rolling, cold rolling and coiling may be considered forging processes, as these involve plastic shaping and create a grain flow consistent with the part.
- Forging Methods
- Cold Working – A process that adds strength and hardness, cold working is the shaping of metal at temperatures well below the recrystallization point of the metal.
- Cross Grain Forging – Done on alternate planes, in cross grain forging a molten metal is poured into a mold to cool with an inverse pattern of grain, beginning from the first area to be cooled and growing inward.
- Drop Forging – A metal shaping process in which metal is heated and formed by rapid closing and opening of a die, which gradually forces the metal to conform to the die cavity’s shape.
- Hand Forging – The deformation of metal using the combination of heat and hammering techniques.
- Hot Forging – A process in which metal is shaped by heating it to a temperature above its recrystallization point, thus softening the metal and making it easier to shape.
- Upset Forging – A bulk forging process in which a heated metal blank of uniform thickness is positioned between split female dies, while a heading die pushes against the metal, thus shaping it.
- Upset/Cross Grain Forging – A combination of upset forging and cross grain forging, this process is done on alternate planes, but also uses the upset forging formation of dies to increase the cross-sectional area of the metal.
- Warm Working – For this process, metals are heated to a point that is typically above room temperature, but below its recrystallization temperature.
Casting and Forging Compared
Casting processes can offer fast repeatability, complex design features and cost-effective processes. However, parts are often weak or brittle due to internal fractures and uneven grain flow. Forged parts tend to have tough mechanical properties and are used in critical applications in many industries. As forged pieces are pounded into shape, the grain flow of the metal changes to follow the shape of the part, giving forgings high strength and ductility. Forges manufacture wheel hubs, gears and valves with maximum strength and durability, while foundries offer the most precise, cost-effective manufacturing for low-performance parts and complex parts such as sink faucets and electronic connector housings.
A Short Video Introduction to Forges and Foundries