So you’re thinking about using some type of rolled steel for your next construction project, but you’re trying to figure out the benefits of hot rolled vs cold rolled steel before you make your move.
Below we’ll cover the differences between hot and cold rolled steel, their applications, pros and cons, and more.
What Exactly Is Rolled Steel?
In the world of metalworking, rolling is the process of forming metal (usually steel) into its final shape by passing it through special machines. These machines use heavy cylinders to flatten the metal into perfectly thin sheets — similar to rolling out cookie dough using a rolling pin.
The metal rolling process is an essential component of most steel mills. Passing metal materials through rolling mills (pairs of roll stands that are grouped together) is what most factories use to shape their metals into finished products.
Therefore, the rolling process — as it pertains to the construction industry — can be used to create structural steel, such as:
- Angle stock
- Channel stock
- Bar stock
- Roofing shingles
- Roofing flash
There are several types of machine rolling as well. This includes:
- Ring rolling
- Roll bending
- Roll forming
- Profile rolling
- Control rolling
- Flat rolling
Each of these types of steel rolling is used to form the metal into a specific shape. Flat rolling, in particular, is what’s used to create sheets of steel — which can be done via hot or cold rolling.
Hot Rolled Vs Cold Rolled Steel
Now that we know what steel rolling is, what’s the difference between hot rolled steel and cold rolled steel?
- Hot rolled steel is steel that has been roll pressed at a temperature of over 1,700°F. High temperatures make the steel more malleable and, therefore, easier to work with.
- Cold rolled steel is created when steel is passed through various rollers after it has cooled down from the initial production process )which involves heat). Due to being shaped at room temperature, the steel becomes more resistant to deformation.
Now let’s cover the differences between the two types of rolled steel in more detail:
Both hot and cold rolled steel vary in their appearance after they’ve been shaped.
- Hot rolled steel will have a noticeable scaly surface. These scales are caused by surface bubbles that occur during the heating process. As the steel cools, these surface bubbles harden, becoming permanent fixtures in the finished product.
- Cold rolled steel presents with a flat and smooth finish with very few deformations. Therefore, the surface of cold colled steel will be shiny and feel slick to the touch.
It should also be noted that heating the steel changes its shape. For example, hot rolled steel bars will have a slight trapezoid shape, whereas cold rolled metal bars will be straight and square.
Both types of rolled steel perform differently in their applications.
- Hot rolled steel performs better where exact dimensions aren’t needed, such as for railroad tracks and certain construction applications. This is due to its inherent softness caused by heating it at such high temperatures.
- Cold rolled steel is generally harder, stronger, and significantly more resilient. This is because the metal is shaped at cooler temperatures, which fortifies it to withstand high tension and damage.
While cold rolled steel is known to be stronger, there is one caveat: If extra treatments are applied to this type of rolled steel, it can cause chemical stress from the inside out, which leads to warping.
The way these types of rolled steels can be used is also important.
The applications of hot rolled steel include:
- Pipes and tubing
- Door construction
- Shelving construction
- Railroad tracks
- Car parts
- Certain types of construction projects
The applications of cold rolled steel include:
- Household appliance creation
- Furniture construction
- Filing cabinet manufacturing
- Locker manufacturing
- Any type of construction project that requires precision and accuracy
Lastly, there are a few other differences to take note of:
- Hot rolled steel is typically cheaper to buy as less processing is required during its manufacturing.
- Cold roll steel tends to require more processing after it cools down from the initial manufacturing process. This can cause stress to occur during the quenching process if not done correctly.
- Since hot rolled steel can cool naturally at room temperature, internal stress doesn’t occur.
The Pros and Cons of Hot Rolled and Cold Rolled Steel
While it may seem like cold rolled steel is the winner of the two materials, it’s important to understand that each comes with its own set of pros and cons.
🔥Hot Rolled Steel Pros:
- It’s more cost-effective
- It takes less time to manufacture and process
- The end result has rounded edges, making it easier to work with
- There’s no concern for internal stress due to its cooling process
🔥Hot Rolled Steel Cons:
- The finished product has a rougher surface (which does not equate to strength)
- It’s less durable as it’s inherently softer
- It doesn’t have a refined, precise shape
🧊Cold Rolled Steel Pros:
- The finished product has a smoother and nicer-looking surface
- It’s very durable and therefore longer lasting
- The finished product has a more refined and precise shape
🧊Cold Rolled Steel Cons:
- It’s more expensive
- It takes longer to manufacture and process
- The end result has sharp edges, which can be dangerous if not handled appropriately
- It can warp internally from stress if not processed or cut to size correctly
Which Is Right for Your Next Construction Project?
The biggest factor that determines whether you should use hot or cold rolled steel depends entirely on your construction process. Each has its own specific applications for use, which means that for most projects, you can’t get away with using either.
When it comes to construction materials, the decision of which is best for what project should be left up to the experts. APX Construction Group can take care of everything you need, from the pre-planning phase to the final touches. Get in touch with us today to learn more about how we can help you with your next construction project.