A sheet is a thin, plain piece of metal designed by an industrial process. A sheet is amongst the most basic metalworking forms, and it can be cut and curved across many varieties of shapes. Sheet metal is often used to explore a variety of imported goods. Extremely thin sheets are labeled as foil or leaf, whereas sections thicker than 6 mm (0.25 in) are labeled as plates.

Moving towards the difference which is between hot and cold rolled steel is as follows- 

Hot Rolled Steel 

Hot-rolling is a mill technique that includes rolling steel at temperatures greater than its recrystallization temperature, this is often beyond 1000° F. Steel becomes more elastic and can be appropriately shaped and molded once heated past its recrystallization point. Thus it enables the production of larger volumes of steel.

Due to the fact that it is frequently created without any interruptions and does not require warming of the steel again and again it is relatively low in cost as compared to Cold rolled steel. When the steel cools, it shrinks slightly, allowing for less control over the size and shape of the completed product than cold-rolled steel.

The surface finish of hot-rolled steel is typically scaly. Scales can be removed using a number of strategies, such as pickling, grinding, and sandblasting, in scenarios where the material’s appearance is a concern.

Because of these features, hot-rolled steel is ideally suited for structural components and other applications where precise forms and tolerances aren’t required.

Cold Rolled Steel 

While hot rolled steel is heated and cooled until being rolled again, cold-rolled steel is heated and chilled at room temperature before being rolled again. The steel is then processed in cold reduction mills, where it is cooled (to room temperature) before being formed using either press-braking or cold roll shaping to create the right shape.

The word “rolled” is frequently attributed to a number of finishing procedures such as twisting, grinding, and polishing, all of which refine existing hot rolled stock. The term “cold rolled” mainly refers to sheets that are compressed between rollers. But forms like bars or tubes are “drawn” not rolled. And once hot-rolled bars and tubes have cooled down, are processed into tubes and bars that are referred to as “cold finished.”

When compared to hot-rolled goods, all cold products have a better surface polish, tolerance, concentricity, and straightness.

Because of the higher carbon content, cold finished bars are much more difficult to deal with than hot-rolled bars. This cannot be said, however, for cold-rolled and hot-rolled sheets. The cold-rolled product has a lesser carbon content than the other two.

How can you differentiate between the two?

The surface of hot rolled steel is scaly, with slightly curved edges and corners, and therefore is non-oily. The surface of cold-rolled steel is oily or greasy, with a really smooth surface and very sharp edges.