Choosing the right type of rolled steel for metal fabrication, whether for machine shop output or a residential construction project, can impact the quality and appearance of your final product. Even though both cold rolled and hot rolled steel offer versatility, sustainability and durability, other characteristics of the two kinds of steel should determine which one you use for a specific project. If you need a primer on the differences between the two, the following guide provides with you the basics of what you need to know.
Steel is an iron alloy that contains small amounts of carbon and other minerals. However, end products made from steel have different properties depending on how the metal is processed at steel mills.
Hot rolled steel is processed at a very high temperature, hence the name, causing the grains of the material to re-form as the steel cools down. Cold rolled steel is processed at near room temperature.
Both types of steel are passed or drawn through rollers during the production process until the desired flatness and shape is achieved. While it is easier to flatten heated steel, the material will shrink during the rolling process. As a result, the final shape of hot rolled steel will be less predictable than cold rolled products.
Characteristics and Benefits
When you need steel for projects that require the material to be cut with extreme precision, you should choose cold rolled steel. Because it does not shrink and has fewer imperfections than hot rolled steel, it can be formed and cut to more specific dimensions. It is also more ductile and durable but less flexible than hot rolled steel.
On the other hand, you can purchase larger sized sheets of hot rolled steel. In addition, you can order galvanized hot rolled steel that is corrosion resistant.
Overall, when you're choosing steel sheets, you should take into account how easy it is to form and weld the material into the shape you need.
Appearance and Finish
If you are working on a project that requires aesthetically pleasing steel, your choice between cold or hot rolled metal will be easy. Cold rolled steel looks better than hot rolled steel because it has a smoother finish.
It is also easier to modify the finish of cold rolled steel because it is not scaly and can be processed to have a matte finish to make it easier to paint, lacquer or enamel. In addition, you can add surface treatments to cold rolled steel to make the material resistant to rust.
The rougher, carbon scale finish of hot rolled steel makes it less amenable to paint and other aesthetic treatments. Since hot rolled steel has a scaly, gray finish, it is more useful for projects where the final product is out of sight or aesthetics are not a priority.
Uses and Price
Cold and hot rolled steel are commonly used for a variety of construction, home improvement, industrial and utility projects. Since cold rolled steel has a more uniform finish and precise shape, it is commonly used for:
- Car parts
- Plumbing fixtures
- Industrial tubing
- Electrical motor parts
- Sleek countertops
- Steel furniture and doors
Typical uses of hot rolled steel include:
- Construction beams
- Railroad tracks
- Massive round, square and rectangular bars for building projects
- Steel plates
When it comes to price, cold rolled steel is more expensive than hot rolled material. However, if you do not want to worry about unpredictable changes in shape during the machining process and want to have options for finishing the material, you should bite the bullet and invest in cold rolled steel.
If you have further concerns about what type of steel to purchase, when you contact a steel supplier and submit specifications for your project, the salesperson should be able to help you choose the exact type of hot or cold rolled steel you need.