I know you are very interested in learning about what hot rolled steel is used for. But guess what Buzz readers, it is actually used for some interesting applications.
Like we discussed in the Hot Rolled Steel: How it is Made post, hot rolled steel is the most basic form of steel a mill produces. Due to its lackluster surface finish it is typically used in applications in which the finish isn’t critical to the project.
While the word “lackluster” is something most people would use to describe this dull, boring type of steel, it is actually one of the more interesting in appearance (besides galvanized which we will get to later). Hot rolled dry sheets and coil are a darker grey than most other steel types and have a silvery blue, almost purple strip along both sides. The color of the strip makes the steel’s surface appear as if it is still hot to the touch. However, this is a result of the hot rolling process and the left-over mill scale.
Because of the unique finish, hot rolled dry is one of the most commonly used steel types for art sculptures (besides stainless steel). The variations of color along the steel sheets provide for character throughout the sculpture.
The down side to hot roll dry is that because it does not have a finish it is prone to rusting. However, you may notice a sculpture in a hotel lobby, airport, or office building that appears to have a rusted finish. The sculpture was likely built from hot rolled dry and allowed to rust before adding a protective finish (or it could have just been sandblasted to look like rust, either way it is likely still hot rolled).
Okay, so maybe you aren’t an art enthusiast. Hot rolled is also used for truck frames and automobile seat frames. For this application the metal typically goes through the processes of pickle and oiling (P&O) before it is used to help prevent rusting and allow for painting.
Hot Rolled Pickle and Oiling Process
The P&O process is a mill scale cleansing that removes the black oxide scale. After the P&O process, an enhanced surface finish is applied and the material is now known as hot rolled P&O.
Hot rolled P&O has a smoother, more even finish. It no longer has prominent, colorful strips along the sides and is slightly less dark in color.
So you’re not into art or automotive, well then maybe you’re a farmer. Hot rolled steel is used widely in agriculture equipment because of its high strength level and formability. The formability of hot rolled P&O can be simple bends to complex draws depending on the steel grade. Harvesters, tractors, and other farm machinery all require the strength that hot rolled offers. Next time you are harvesting your grains, remember you are probably riding on a big green hot rolled machine (red in this case).
None of these areas interest you? Well, lucky for you there are other uses for hot rolled and hot rolled P&O, including water heaters, railcar components and railroad equipment, guard rails, doors, shelving and many more.