What is hot rolling

define

Hot rolling is relative to cold rolling. Cold rolling is rolled below the recrystallization temperature, while hot rolling is rolled above the recrystallization temperature. A piece of billet is heated and rolled several times, and then trimmed to become a steel plate. This is called hot rolling. It can significantly reduce energy consumption and cost. During hot rolling, the metal has high plasticity and low deformation resistance, which greatly reduces the energy consumption of metal deformation. Hot rolling can improve the processing properties of metals and alloys, that is, the coarse grains in the casting state are broken, the cracks are healed significantly, the casting defects are reduced or eliminated, the cast microstructure is transformed into deformed microstructure, and the processing properties of alloys are improved.

performance

Hot rolled products have high strength, good toughness, easy molding and good weldability. Hot rolling is made by heating rolling at high temperature to recrystallize the inside of the steel and make it better.

The advantages and disadvantages

Advantages :1. It can destroy the casting structure of steel ingot, refine the grain of steel, and eliminate the defects of microstructure, so that the steel structure is dense, and the mechanical properties are improved.

2. Hot rolling can significantly reduce energy consumption and cost. During hot rolling, the metal has high plasticity and low deformation resistance, which greatly reduces the energy consumption of metal deformation.

3. Hot rolling usually adopts large ingot and large pressure rolling, which not only improves the production efficiency, but also creates conditions for improving the rolling speed and realizing the continuity and automation of the rolling process.

Disadvantages :1. After hot rolling, the non-metallic inclusions inside the steel (mainly sulfide and oxide, and silicate) are pressed into thin slices, and the phenomenon of lamination (sandwich) occurs. Delamination greatly deteriorates the tensile properties of the steel along the thickness and may cause interlaminar tearing when the weld seams contract.

2. Residual stress caused by uneven cooling. The residual stress is the internal self-phase equilibrium stress without external force. All kinds of hot rolled steel sections have this kind of residual stress. Generally, the larger the section size of steel, the greater the residual stress. Although the residual stress is self-phase equilibrium, it has a certain influence on the properties of steel components under external force. Such as deformation, stability, fatigue resistance and other aspects may have adverse effects.

application

1, suitable for general structural steel and engineering hot rolled steel plate, steel belt, for pipe welding, cold rolled material, bicycle parts, and important welding, riveting, bolted components.

2, used for cold rolling, deep drawing products.

3, the production of cars, tractors, engineering lifting machinery, small light industrial civil machinery stamping and structural parts.

4. Make containers and bare metal structural parts.

5, welded pipe, steel structure.

6. Pipelines for transporting oil and natural gas.

7. Car girders and beams.

8. Special steel belt for car wheels.

9, structure with anti-skateboard, stairs, ladder pedal, etc.