Difference between hot rolling and cold rolling of square and rectangular tubes

Square tube and rectangular tube production process:

Square tubes and rectangular tubes are usually made of steel plates or steel strips through cutting, bending, welding and other processes. Cold rolling and hot rolling are often used in production, which will affect the structure and performance of square tubes to varying degrees. The common material for square and rectangular tubes is ASTM A500.

Cold rolling refers to pressing and stretching steel plates or steel strips at room temperature to adjust the thickness and size to make square and rectangular tubes. During the cold rolling process, the processing pressure is small and excessive heat is not generated, so the mechanical properties of the raw materials can be kept unchanged. The square and rectangular tubes produced by the cold rolling process have high surface finish and high dimensional accuracy.
 

Hot rolling requires heating the raw materials to a higher temperature for processing, usually above 1000°C. Steel is easy to deform under high temperatures, so steel plates or steel strips are stretched, flattened, pressed, etc. to make square and rectangular tubes. The square and rectangular tubes produced by the hot rolling process have a low surface finish and relatively low dimensional accuracy.

The difference between cold rolling and hot rolling:

1. Different processing temperatures
Cold rolling is performed at room temperature, while hot rolling requires heating the raw materials to above 1000°C.

2. Different processing pressures
Cold rolling processing pressure is smaller, and hot rolling processing pressure is larger.

3. Different mechanical properties
Since excessive heat is not generated during cold rolling, the mechanical properties of the steel can be kept unchanged, while hot rolling at high temperatures will affect the mechanical properties of the steel.

4. Surface finish and dimensional accuracy are different
The square and rectangular tubes produced by the cold rolling process have high surface finish and high dimensional accuracy; the square and rectangular tubes produced by the hot rolling process have a low surface finish and relatively low dimensional accuracy.

Application of cold rolling and hot rolling in the production of square tubes and rectangular tubes:
Cold rolling is mainly used to make square and rectangular tubes with smaller sizes and higher precision requirements, such as brackets and bearing covers for electronic equipment. Hot rolling is mainly used to make square and rectangular tubes with larger sizes and lower precision requirements, such as Building structures, mechanical frames, etc.
 

To sum up, both cold rolling and hot rolling are commonly used processes in the production of square tubes and rectangular tubes. The square tubes and rectangular tubes produced by the cold rolling process have high surface finish and high dimensional accuracy, while the square and rectangular tubes produced by the hot rolling process have low dimensional accuracy and poor surface finish. In practical applications, choosing the appropriate process according to needs can better meet the needs.

Go here to learn more about " ASTM A500 Square Tube"

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