Hot Rolled Steel Vs. Cold Rolled Steel

Metal is still an incredibly important material for many fields, including technology, construction, aerospace and many others. However, before the metal can be used, it is often hot rolled and/or cold rolled. If you aren't sure what these terms mean or why one is better than the other, you need to check out these four FAQs.

What Does Hot Rolled Mean?

Hot rolled simply means the metal was treated with heat to mold it and stretch it. The temperature is high enough to turn the metal soft, this makes it malleable, so it can be molded into different shapes and stretched. This type of process is extremely common when it comes to creating I-beams, railroad tracks and other materials that don't need to be extremely precise.

What Does Cold Rolled Mean?

Cold rolling is a process that is used to strengthen the metal but below the metal's recrystallization temperature. Typically, this means it is done at about room temperature. Basically cold rolling takes metal that has already been treated with hot rolling and it further treats it to improve the metal further. The cold rolling process smooths and perfects the metal. Cold rolled metal is commonly moved in appliances, automotive components and building frames.  

What Are the Pros and Cons of Hot Rolled Steel?

One of the biggest advantages of hot rolled steel is that it is more affordable to manufacture than cold rolled steel, and because the process is rarely interrupted, the metal doesn't need to be repeatedly reheated. The hot rolling process does also make the metal stronger and more durable, which is extremely important since the metal is often used with big equipment like trains.

There are, unfortunately, quite a few disadvantages of hot rolled steel. One of the first problems is that it's hard to know what the exact dimensions will be once the metal is cooled. This is because during the hot rolling process, the metal shrinks. Therefore, the shape and size of the steel are hard to predict before the metal is cooled. The last disadvantage of hot rolled still is that it isn't great to look at. It has a scaly grey finish, and the corners are more rounded, less precise. This is why hot rolled steel is better for components that don't need to be precise or near perfect.

What Are the Pros and Cons of Cold Rolled Steel?

Cold rolled steel is more expensive to manufacture than hot rolled steel. Similarly, because cold rolling is performed on metal that has already been hot rolled, you may have to consider the cost of hot rolling the metal and then cold rolling it. Another disadvantage is the cold rolling process removes the protective oxide surface that is created during the hot rolling process. Without this protective cover, the treated metal must be handled carefully to protect the smooth surface.

On the other hand, there are incredible advantages of cold rolled steel. For starters, because it isn't heated during treatment, there is no need to worry about the steel shrinking or changing its shape. It's much easier to predict what the finish piece will look like. This is why cold rolled steel is typically used for parts that require a bit more perfection. The last advantage cold rolled steel has over hot rolled is that it is stronger. Cold rolled metal is a better tensile and yield strength, so it is less vulnerable to pressure.

Cold rolled steel creates finished metal that is nearly flawless, making it perfect for many important parts. If you believe cold rolling is something your business needs to consider, contact an equipment provider in your area today and start asking your questions.