Brass forging is a process in which a forging press places extreme
pressure on a single piece of brass or brass alloy that has been
heated to about 1,500 degrees F (815 degrees C). The softened metal
is then forced, beaten, and shaped to produce a part made from a
single piece of brass and free of imperfections. Different methods
of brass forging can create just about any type of three-dimensional
shape or form, weighing anywhere from a few ounces to several tons.
The various types of brass forging include impression or closed die
forging, open die forging, cold forging, and seamless rolled ring
brass forging process actually makes the metal around 15% stronger
than mold cast parts as the process does not change the structure of
the metal. Extruded brass stock is made into a shape already close
to the final part that it will be forged into when the brass is
heated. Forging brass parts reduces metal scrap and is faster than
machining the parts. The forging process also produces a pore-free
surface which makes for a more attractive brass part.
Closed die forging, also known as impression-die forging, utilizes
two or more dies made in the shape of the part desired. The brass is
heated until it becomes malleable, or reaches a plastic state, and
is then compressed by the die machine. Some die machines are capable
of creating a compression force of 5,500 pounds (2,500 kg) or more
to create forged parts. This forging process creates brass parts
that have enhanced density, aligned grain flow, and high strength.
In this process, brass parts may also be curved or bent on one or
more planes. While more expensive than brass casting methods, closed
die brass forging produces extremely strong and durable products.
In open die forging the heated, malleable brass is not confined in a
die or mold. Instead, it is accomplished with the use of two flat
die surfaces with no type of impression. This type of brass forging
is typically used to create and shape very large single pieces of
brass up to 80,000 lbs (36,363 kg) or more. This open die process is
typically used for lower quantity production runs and custom brass
forging on larger parts.
While most forging is done at extremely high temperatures, cold
brass forging only requires that the brass be heated to a few
hundred degrees. Cold forging is typically used to create things
like coins, automotive steering parts, anti-lock braking systems,
and other smaller parts that weigh less than 10 lbs (4.5 kg). This
process produces parts that require high strength and close
Rolled ring forging uses round, open ring-shaped parts that were
shaped using the open die forging process. This type of forging is
accomplished through the forced pressure of two axial rolls, a
driver roll and an idler roll. The ring of brass is rotated by the
idler roll while applying pressure to the inside of the ring. The
driver roll applies pressure to the outside edge of the ring. As the
process progresses, the ring becomes flatter until the desired ring
diameter is achieved.