|Hot Rolled Sheet
|KG Per Sheet
|1800 x 1200 x 1.6
|2400 x 1200 x 1.6
|1800 x 1200 x 2.0
|2400 x 1200 x 2.0
|2400 x 1200 x 2.5
|1800 x 1200 x 3.0
|2400 x 1200 x 3.0
|3000 x 1200 x 3.0
|3660 x 1200 x 3.0
|2400 x 1500 x 3.0
|3000 x 1500 x 3.0
|2440 x 1220 x 4.0
What’s the difference between hot rolled and cold rolled steel?
It’s important to note that the main difference between hot rolled and cold rolled steel is one of process.
Hot rolling refers to processing done with heat.
Cold rolling refers to processes done at or near room temperature although these techniques affect overall performance and application they should not be confused with formal specifications and grades of steel which relate to metallurgical composition and performance ratings.
Steels of different grades and specifications can be either hot rolled or cold rolled including both basic carbon steels and other alloy steels.
It may seem obvious, but some types of steel are better suited for certain applications, knowing which to use can help avoid overspending on raw materials, it can also save time and money on additional processing.
Understanding the differences between hot and cold steel is integral to choosing one over the other.
Hot rolled steel is steel that has been roll pressed at very high temperatures which is above the ray crystallization temperature for most steels.
This makes the steel easier to form and resulting in products that are easier to work with.
To process hot rolled steel manufacturers first start with a large rectangular length of metal called a billet. The billet is heated and then sent for pre-processing where it is flattened into a large roll from there it is kept at a high temperature and run through a series of rollers to achieve its finished dimensions. The white-hot strands of steel are pushed through the rollers at high speeds for sheet metal rolled steel is spun into coils and left to cool.
For other forms such as bars or plates the materials are sectioned and packaged.
What are the benefits of hot rolled steel?
Hot rolled steel typically requires much less processing than cold rolled steel which makes it a lot cheaper because hot rolled steel is allowed to cool at room temperature.
It’s essentially normalized meaning it’s free from internal stresses that can arise from quenching or work hardening processes hot rolled steel is ideal where dimensional tolerances aren’t as important as overall material strength and where surface finish isn’t a key concern.
Where surface finish is a concern scaling can be removed by grinding sand blasting or acid bath pickling once scaling has been removed. Various brush or mirror finishes can also be applied, descaled steel also offers a better surface for painting and other surface coatings.
Cold rolled steel cold rolled steel is essentially hot rolled steel that has been through processing once hot rolled steel has cooled. It is then re-rolled at room temperature to achieve more exact dimensions and better surface qualities.
Cold rolled steel is often used to describe a range of finishing processes though technically cold rolled applies only to sheets that undergo compression between rollers.
Steel forms that are pulled such as bars or tubes, are drawn not rolled.
Other cold finishing processes include turning grinding and polishing, each of which is used to modify existing hot roll stock into more refined products.
What are the benefits of cold rolled steel?
With better surface characteristics than hot rolled steel it’s no surprise that cold rolled steel is often used for more technically precise applications or where aesthetics are important.
But due to the additional processing for cold finish products they come at a higher price.
In terms of physical characteristics cold rolled steels are typically harder and stronger than standard hot rolled steels as the metal is shaped at lower temperatures.
The steel’s hardness, resistance against tension breaking and resistance against deformation are all increased due to work hardening.
These additional treatments however can also create internal stress within the material this can cause unpredictable warping if the steel is not stress relieved prior to cutting grinding or welding.