Which method can help reduce force in flat rolling?

Using hot rolling is an effective method for reducing force in flat rolling processes. Hot rolling involves deforming metal at elevated temperatures, which significantly lowers the yield strength of the material. This means that when the metal is subjected to the rolling process, it requires less force to achieve the desired shape compared to cold rolling, where the material is processed at or near room temperature.

In hot rolling, the increased temperature allows for easier deformation of the metal structure, leading to a reduction in the resistance that the material presents during the rolling operation. This results in a smoother flow of the metal through the rolls and less energy required to produce the desired thickness.

While cold rolling can also be employed for various benefits, its primary focus is on improving surface finish and dimensional accuracy at the cost of greater force required due to the higher yield strength of materials at lower temperatures. Similarly, increasing draft in each pass typically raises the required force, as it involves a larger reduction in thickness per pass. Using larger diameter rolls can lead to lower contact pressures and reduce force to some extent, but it does not provide the same level of reduction in force as hot rolling by itself, particularly due to the temperature advantages. Thus, hot rolling stands out as the method that most effectively helps to reduce force