Advantages and disadvantages of hot rolled steel

By definition, steel ingots or billets are difficult to deform and process at room temperature. They are generally heated to 1100°C to 1250°C for rolling. This rolling process is called hot rolling. Most steels are rolled by hot rolling. The steel delivered in the hot-rolled state has a certain degree of corrosion resistance due to the high temperature, so it can be stored in the open air.

Advantage:

Hot rolling has fast forming speed, high output, and does not damage the coating. It can be made into a variety of cross-sectional forms to meet the needs of use conditions. Cold rolling can cause large plastic deformation of steel, thereby improving the yield of steel point.

Disadvantage:

1. After hot rolling, the non-metallic inclusions in the steel are pressed into thin slices, and delamination occurs. Delamination greatly deteriorates the tensile properties of the steel in the thickness direction, and it is possible that interlayer tearing may occur when the weld shrinks. The local strain induced by weld shrinkage often reaches several times the yield point strain, which is much larger than the strain caused by the load.

2. Residual stress is the internal self-balanced stress without external force. Hot-rolled steel sections of various cross-sections have such residual stresses. Generally, the larger the section size of the steel section, the larger the residual stress. Although the residual stress is self-balanced, it still has a certain influence on the performance of the steel member under the action of external force. For example, it may have adverse effects on deformation, stability, fatigue resistance, etc.

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