Copper

As mentioned before, copper is well-known for its thermal and electrical properties. Its main application is electrical wiring.

Copper is reddish-to-orange in color, highly malleable, very ductile, and commercially pure copper has excellent corrosion resistance.

Because of its low melting point, copper can be recycled without much effort, reducing its manufacturing costs.

Copper is used in the HVAC industry as part of coolant tubing and in the electronic industry for computer chips and other components such as wiring.

Being extremely malleable, copper is also used for sculptures and other decorative purposes. The statue of liberty is made of copper on both the inside and the outside.

Copper is a dense material, it can up to 2g/cc heavier than steel. This is the main flaw that won’t let it be used in most structural applications. For its corrosion resistance, it may also be used for tubing for gas and water.

Commercially pure copper is represented by the UNS numbers. Its designation grades go from C10100 to C13000 and they differ from each other because of the impurities contained.

Most grades contain up to 0,7% oxygen. Oxygen affects both thermal and electrical conductivity turning it into the worst impurity.

In most cases, copper has poor machinability, but at low speeds with proper cooling, it is machined with ease.

Copper grades are heat-treatable and hardened by cold working. Each grade is specified by the aging process applied. Some of the most popular commercially pure grades are presented below:

1. UNS C11000 OSO25 Temper

99.9% pure copper with a small concentration of oxygen, this grade keeps the excellent corrosion resistance of most commercially pure copper grades. It has good formability, workability, and it is forged with ease. Being such a soft material it is perfect for stamping and flat products such as sheets and rectangular profiles.

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2. UNS C13000 H80 Temper

99% copper with small amounts of silver, nickel, selenium and others. The small presence of these materials considered as impurities enhances the mechanical properties of copper. It has a better wear resistance and its suitable for extrusion, welding, sheet fabrication, stamping and almost every forming and forging method. Common applications include gutters, downspouts, automotive radiators, and air conditioner tubing.

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3. UNS C12200 Extra Hard (H06)

With 99,8% copper and 0,2% phosphorus, the UNS C12200 maintains the magnificent thermal and electrical properties that characterize any commercially pure copper, but it weighs slightly more than the usual. Not having oxygen is a plus, enhancing both thermal and electrical conductivity. It has adequate strength, can be machined at low speed, and is easily formed, worked, and welded. Regular applications include evaporators, condensers, gas and heater lines, water piping, fuel lines, and oil burner tubing. It has excellent corrosion resistance.

√ Manufacturing Processes Performance

√ Mechanical Properties

Even though copper has an amazing appearance, it requires a surface finishing process to enhance its properties and to make it more durable. When used in piping, water lines, and gas lines applications, it is common to apply a plating of other metal to strengthen its surface. The most common surface finishing’s applied are:

1. Electroplating

This process involves the addition of another metal to the product surface via electrolysis. The main goal of an electroplating process is to provide better wear resistance to the copper product to make sure it can withstand a harsh environment. Copper is frequently plated with tin, silver, nickel, chrome, and even gold.

2. Shot-blasting

Much like a regular sand-blasting process, the main difference of this process is that it uses fine metal powder (frequently steel) to remove impurities from the product’s surface. The finer the powder, the better finishing is obtained. Shot-blasting is also used to smoothen the product’s surface.

3. Polishing

Manual polishing is a very common process applied to copper products to enhance the surface’s appearance and to extend the durability of the product. Manual polishing requires more time and effort than other surface treatments applied, making it more expensive. A polished surface not only enhances the appearance of the product; it also improves corrosion resistance.

Copper is mostly used in HVAC and heat-exchanging applications, but it can also be used in other common applications in which corrosion resistance is required. For its appearance, it is frequently used in sculptures and decoration.

Here are some tips to consider when designing a copper product:

• Its corrosion resistance and durability combined with excellent thermal properties make it an excellent replacement for aluminum in heat-exchanging applications, the main drawback of this application is its weight.
• Around 12 million tons of copper are produced every year, and at least 4 million of those tons can be obtained by recycling processes. Its availability and ease of recycling make copper a cheap material.
• Applying a metal plating can extend the duration of your copper product.
• Copper can be hardened and manufactured in a wide variety of processes, making it a versatile material, capable of achieving any shape with high strength levels.