Steel can have its properties significantly altered depending on how it is processed – hot rolled steel has a rough, dull surface with visible scale, while cold rolled steel has a smooth, clean finish. Here we help you understand the differences between these two types of steel so you can select the right material for a specific engineering purpose.
What is Hot Rolled Steel?
Hot rolled steel is used in sheet metal fabrication, such as at https://dkmsheetmetal.co.uk/ – produced by rolling the steel at very high temperatures, typically above 900°C, which is above the metal’s recrystallisation temperature. At this temperature, the steel becomes soft and highly malleable, so it can be easily shaped and formed into large sections such as sheets and plates.
During the hot rolling process, the steel is passed through rollers to achieve the desired thickness. After rolling, the steel is cooled at room temperature, which can lead to slight shrinkage and less precise dimensions if you’re not careful.
What is Cold Rolled Steel?
Cold rolled steel is produced by further processing hot rolled steel at or near room temperature. After the initial hot rolling, the steel is cooled and passed through rollers again without reheating – increasing the strength of the material. Because the steel is not heated during this stage, it becomes harder and stronger due to strain hardening.
Cold rolled steel is commonly used in products such as car body panels, some appliances and furniture. However, it is more expensive than hot rolled steel due to the extra processing that is involved.
