The Differences Between Cold and Hot Rolled Steel

Steel kitchenwares

Steel is one of the most important and widely used materials around the world. As it can be recycled over again (without losing any of its properties), you can find it almost everywhere, specifically in products used and/or manufactured by the appliances, construction, energy, packing, and transport sector. Which means that you can find it in your car, your roofing and cladding, and even in your household appliances.

It’s best to remember that steel is an alloy of iron, with varying amounts of carbon (about 0.5% to 1.5% content). It shouldn’t be used interchangeably or mistaken as metal. Metals are elements naturally present in the Earth’s crust, while steel is a variation of iron metals and is therefore not a pure element.

According to the World Steel Association, steel isn’t a single product since it has thousands — more than 3,500 — of different grades with varying physical, environmental, and chemical properties. Moreover, its high tensile strength makes it ideal for fabrication.

What is Steel Fabrication?

Steel fabrication is a complex process that’s best left to the hands of experts. For consumers, it’s still essential to learn the differences among its available products. This will be necessary to help you choose the right type of steel for a particular project.

Among the many options, however, two create the most confusion: hot and cold rolled steel. But are there any difference between them?

When it comes to the grade and quality, both hot and cold rolled steels can be the same. The general procedure is not different either. Manufacturers create them by inserting the metal to rollers to decrease its thickness.

Hot Rolled Steel Process

Sharpening of a steel knifeWhat sets them apart is the specific milling process. Producing hot rolled steel involves a temperature past the metal’s recrystallization. Usually, it’s above 727º Celsius.

In chemistry, metals have particles that appear like grains. When exposed to specific temperatures and force, these small parts can change. They may also acquire characteristics that will make them ideal to certain types of projects. For example, there may become more flexible or stress resistant.

Hot rolling can help create a variety of steel shapes. The downside is the particles can reassemble once the product cools down. It’s a better option for those who want cheaper steel with no specific dimension or tolerance requirements.

Cold Rolled Steel Process

The cold-rolled steel refers to hot-rolled steel that undergoes more processes. These include milling at room temperatures and annealing.

Annealing is a process of slowly reheating a cold metal. During the milling procedure, the cold rolled steel can become tough or hard. Manufacturers cannot shape it in any form. Annealing resolves the problem and provides other benefits. It can increase the flexibility or the tolerance of the product.

Cold-rolled steel is more expensive than the other due to the additional processes. For those who have specifications, this is the material to use.

When you aren’t sure which type of steel to use, discuss it with the manufacturer. They can also walk you through the process to help you understand the benefits and challenges of each.

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