Thursday, July 26, 2018

Understanding The Difference Between Cast Metal and Wrought Metal

Many people use the terms “cast metal” and “wrought metal” interchangeably, but the two actually
refer to very different processes. Cast metal has been melted, molded, and cooled. Wrought metal has
been heated and then worked with tools. Here is what you should know.
Cast Metal
Any metal that can be wrought can also be cast. However, both cast metal and wrought metal are
generally alloys rather than pure metals, and their compositions are different. This means that when
compared to wrought metal, cast metal is harder, more brittle, and less malleable.
Cast metal has a relatively low tensile strength, which means that it is likely to break rather than bend,
but it has a high compression strength, making it useful for constructions and other applications where
it needs to hold significant weight. Cast iron, for example, was a common building material from the
18th century until it was replaced by steel in the early 20th century.
Wrought Metal
Wrought metal is heated and then worked with a hammer and other tools while hot before being
cooled. It is softer and more ductile than cast metal. Since it is extremely malleable, wrought metal
can be reheated and reworked over and over again. This reworking actually strengthens wrought metal
rather than damaging it.
Wrought metal has a very high tensile strength, making it ideal for applications such as horizontal
construction beams that must deform and reform regularly. It is extremely resistant to fatigue, and it is
unlikely to break unless it is distorted from intense heat such as a fire or is severely overloaded.
Today, wrought metal is mostly used as a decorative material.
Corrosion
Some metals form a protective oxidative coating over time, while others are susceptible to corrosion.
Both cast iron and wrought iron are particularly at risk for corrosion, especially in areas of high
humidity and frequent precipitation. Consequently, both need to be protected in some way. Paint and
powder coatings are two of the most common ways to protect bare metal.
A powder coating consists of a polymer resin mixed with a variety of additives such as leveling agents,
curatives, flow modifiers, and perhaps pigments. The ingredients are melted, mixed, cooled, and
ground into a power that resembles baking flour. The powder is then loaded into a special electrostatic
spray gun that gives it a negative charge and applies it evenly to the metal item. The metal then enters
a curing oven where it is baked to create a chemical reaction that ensures even, long-term adhesion.
Powder coatings are highly durable and are not prone to flaking, fading, cracking, or chipping.
Both cast metal and wrought metal can be highly decorative as well as extremely functional. Yet the
two are not interchangeable. It is important to understand the differences in order to purchase the
product that best meets your needs and desires.
Ready to Start?
Atlas Bronze is a leading U.S. distributor of bronze, copper, brass, iron, and more. Contact us today at 1-800-478-0887 to place an order or learn about our custom products.

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