Difference between hot rolled steel plate and cold rolled steel plate

Steel plate is steel that has been rolled into a thin, flat piece. This form of steel is used in a variety of industries including metal material handling and construction. The different uses for hot rolled and cold rolled steel both come down to the temperature at which the material is formed. Hot rolled products like hot rolled steel bars are used in the welding and construction trades to make railroad tracks and I-beams, for example.

What is a cold rolled steel plate

Cold rolled steel plate (steel plate, thin plate), its thickness is below 4 mm, and its surface finish is bright. This kind of cold rolled steel plate is used for precision parts or parts that need to be thin.

Because the material for hot rolled steel plate needs to be heated several times in order to become flexible and then pass through a rolling machine, its thickness cannot reach less than 4mm. After that, it will go through other processes such as cold drawing or heat treatment in order to adjust the shape of the product according to customers’ requirements.

On the contrary, cold rolled steel plate does not require any processing (except for coating). So if you want to make a very thin thing out of hot-rolled plates (such as making small screws), you will have trouble finding suitable materials available at local stores because they don’t stock them

What is a hot rolled steel plate

Hot rolled steel plate, also known as hot rolled steel plate, is a kind of steel plate that has been made by the most common rolling process in which the metal is heated to a temperature between 950 degrees Celsius and 1065 degrees Celsius. Hot rolled steel plate can be divided into ordinary high quality cold-rolled sheet and micro-alloyed structural steels according to its composition.

Hot rolled steel plate is mainly used for structural parts in buildings, bridges and other mechanical parts. The thickness of hot rolled steel plate is 3 mm-8 mm or even more than 8 mm (thickness from 2mm). The minimum thicknesses of hot rolled sheets are usually 0.2mm or 0.3mm (0.25mm).

The differences between hot rolled steel plates and cold rolled steel plates

The differences between hot rolled steel plates and cold rolled steel plates are as follows:

• 1) Hot rolled sheet has a relatively high hardness and strength compared to cold rolled sheet, so it can withstand a certain degree of impact during handling.
• 2) The surface of hot rolled steel plate is usually smooth, which makes its appearance better than that of cold-rolled sheets.
• 3) Hot rolling process can improve the mechanical properties of the material by making it more uniform in thickness and grain size, reducing the content of excessive elements (such as sulfur or phosphorus), improving toughness etc., which affects its performance characteristics greatly; while cold rolling processes are not suitable for producing materials with good deformation processing performance because they cause some changes on material microstructure (especially grain size distribution), making them unsuitable for further heat treatment processes like annealing or quenching after cold rolling.

The hot worked steel sheet has relatively low internal stress and relatively relaxed state.

The hot worked steel sheet has relatively low internal stress and is delivered in a relatively relaxed state. This relaxed state is beneficial for processing and final product because it allows the material to be more easily manipulated, cut and bent during subsequent operations.

Hot worked steel sheets have higher dimensional accuracy than cold worked steel sheets.

When the steel plate is hot, the size tolerance can be more accurate. In fact, the tolerances of hot rolled and cold rolled steel plates are very similar. However, when comparing the dimensional accuracy between a hot worked and cold worked sheet of equal thickness, it is understood that there will be a difference in dimensional accuracy between them due to their different cooling processes.

In addition to adjusting the chemical composition, hot worked sheets are mainly made of continuous casting slabs or hot-rolled coils to perform rough rolling, then reheating and finishing rolling. Cold worked sheets generally use cold-rolled strips as raw materials for mechanical processing; they can also be produced by rolling through intermediates such as annealed cold rolled strips.

Hot rolled steel plates are usually used for mechanical processing, while cold rolled steel plates are commonly used in precision parts and equipment manufacturing industries.

Hot rolling has lower dimensional accuracy than cold rolling

Generally speaking, hot rolling has lower dimensional accuracy than cold rolling. Due to the large deformation caused by rolling at elevated temperatures, it is difficult to control the shape and size during cold working. But if you need large deformation or want to obtain special properties such as improved toughness and ductility through induction annealing process after hot rolling, then it may be necessary to use hot rolling; in short, the general choice of cold working is for precision.

Hot rolled steel plate is made by rolling hot materials in the temperature range of about 750–950 °C (1400–1800 °F). After the steel cools down, it’s shaped into a product. It can be used to make various products such as pipes, structural parts, and cans.

Cold rolled steel plate is made by rolling cold materials at temperatures below 600°C (1100°F). The shape of this product is controlled better than that of hot rolled steel plate because it doesn’t have much deformation during processing. This type of metal can also be used for making pipes, structural parts and cans.

Conclusion

In general, hot rolling has lower dimensional accuracy than cold rolling. Due to the large deformation caused by rolling at elevated temperatures, it is difficult to control the shape and size during cold working. But if you need large deformation or want to obtain special properties such as improved toughness and ductility through induction annealing process after hot rolling, then it may be necessary to use hot rolling; in short, the general choice of cold working is for precision.

Source: Stainless Steel Plate Supplier: www.epowermetals.com

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

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