Rolled Steel: Steel Coils and Their Uses

Of all the ways to store steel, few people outside of our industry would expect that we’d roll it into a steel coil. To the uninitiated, it might feel a little bizarre; most people know steel as the material that upholds skyscrapers and keeps their car in one piece. So, when we talk about rolled steel or steel coils, the average person might think: isn’t the purpose of steel not to roll up or coil?

In truth, rolled steel is essential for many—if not most—daily steel applications. But why is rolling steel so important, and what benefit does a steel coil give us? Today, we’re exploring why we roll steel into steel coils and the benefits it gives us.

Controlling Steel’s Thickness

One of the main reasons we roll steel into steel coils is to control the thickness of the steel sheet. By passing the molten metal stock through pairs of finely tuned rollers, we can precisely determine the thickness of that steel. Naturally, this is an essential process when creating steel for specific uses. Even a slight change to the thickness of a steel sheet can make a considerable difference for anything ranging from home appliances to automotive parts. As a result, it’s essential that we can control our steel’s thickness as accurately as possible.

Recrystallization Benefits (And Avoiding Them)

The process of creating rolled steel breaks down into two end products: hot rolled steel and cold rolled steel. Both types have their own unique strengths and weaknesses stemming from recrystallization (or lack thereof).

Hot Rolled Steel: Benefits of Recrystallization

Hot rolling steel is done by heating steel at temperatures in excess of at least 1000 degrees Fahrenheit. This begins the process of recrystallization, during which the steel is much more malleable and very easy to form.

Pros: Because hot rolled steel undergoes recrystallization, it’s considerably more malleable than cold rolled steel, making it cheaper and quicker to re-form. And because hot rolled steel can cool at room temperature, it won’t face the internal stresses from quenching that cold rolled steel does. As a bonus, it also has increased toughness and ductility.

Cons: Because hot rolled steel undergoes recrystallization through a slow cooling process, it’s also prone to warping. This can create imperfections in the material and surface imperfections, leading to a “scaly” finish that’s less precise and not too pretty to look at.

Some applications for hot rolled steel include: train tracks, metal buildings, automotive frames, agricultural equipment, I-beams, and general-use sheet metal.

Cold Rolled Steel: Preventing Recrystallization

By subverting the recrystallization process, cold rolled steel gains its own unique benefits. Cold rolling steel is done by allowing it to cool to room temperature before processing it.

Pros: Cold rolled steel doesn’t warp like hot rolled steel does, making it perfect for precise applications. At the same time, cold rolled steel can undergo strength hardening that makes it up to 20% stronger than hot rolled steel. Cold rolled steel also has a smooth, oily finish that’s pleasing to look at and touch.

Cons: Cold rolling steel takes longer and more effort than hot rolling steel. Before processing it, the freshly forged steel must return to room temperature, which adds a meaningful wait period. Additionally, processing hardened, cooled steel is much more difficult than malleable, hot steel, making it a more labor-intensive process. As a result, cold rolled steel is less suited for large-scale applications.

Some applications for cold rolled steel include: medical equipment, home appliances, aerospace components, automotive parts, electrical equipment, construction materials.

Get Quality Rolled Steel and Steel Coils from Atlas

Here at Atlas Steel, we always make sure quality and consistency are our top priorities. For a quote on your stainless steel coils, click here to fill out a quote request today!