How to cool the seamless carbon steel tube billet?

Posted by zora li on November 4th, 2022

According to the chemical composition, state structure, product section size, possible deficiencies after cooling, and the rolling mill, cooling equipment, space and cooling conditions of the seamless carbon steel pipe after hot rolling, different cooling methods can be used to cool to room temperature.

1) Air cooling
This is a natural air cooling method and is widely used. After all air cooling, it is not martensitic structure or steel, and air cooling is used after hot rolling, such as low carbon steel, low alloy ordinary strength steel, most of which are carbon steel and alloy semi-martensitic structural steel, and austenitic stainless steel, All use this cooling method.

2) Rapid cooling
It is a method of blowing, spraying, and forced water through cooling, and the steelmaking process is characterized by dramatic cooling for a certain period of time to the temperature of natural cooling. If required, this cooling method is used to detect defects in cemented carbide stencils. After the carbon steel wire rod is rolled, it needs to be rapidly cooled to improve the comprehensive mechanical properties of the wire rod.

3) Slow cooling
It is characterized by hot-rolling or stacking the billets together to cool them slowly to prevent white spot defects. The specific method of slow cooling depends on the production conditions. It can be placed in a special slow cooling pit or a special slow cooling box, stacked on the floor, and slowly cooled with asbestos such as sand and slag. it's cold

However, this method is suitable for martensitic, martensitic and semi-ledeburite steels, such as high-speed tool steels, stainless steels, tool steels and high-alloyed structures with high-alloyed sections, which are very sensitive and strong to the stress generated during cooling.

4) Heat treatment
The heat treatment methods commonly used are annealing, tempering and normalizing after hot rolling.

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