In this topic you study, the difference between Hot Rolling and Cold Rolling.
| Hot Rolling | Cold Rolling |
| In hot rolling process, metal is heated above the recrystallization temperature and is fed to the rolls. | In cold rolling process; metal is heated below the recrystallization temperature and is fed to the rolls. |
| Coefficient of friction between the stock and the rolls is high. | Coefficient of friction between the stock and the rolls is less. |
| Due to high friction coefficient, shearing of metal can take place. | Due to low friction coefficient, shearing of metal does not take place. |
| Work hardening effect cannot be observed after the metal is hot rolled. | Work hardening effect can be observed even after behind rolled. |
| It is difficult to carry out experimental measurements due to temperature variation. | It is easier to carry out experimental measurements. |
| It is difficult to carry out theoretical experiment as for each pass, the yield stress varies with the temperature. Thus, the hot rolling gives more problems in theory formulation. | It is easier to carry out theoretical analysis. |
| Roll radius is very large. | Roll radius is smaller compared to hot rolling. |
| Surface finish obtained in the process is not good due to metal oxides formation. | Surface finish obtained in the process is good and free from oxides. |
| Mechanical properties like strength and toughness of the metal increase. | Mechanical properties like hardness increases but ductility of metal decreases. This rolling increases the tensile strength and yield strength of a steel. |
| This sections are very difficult by the hot rolling. The sheets less than 1.25 mm thickness is not possible. | This sections such as aluminium foils of 0.02 mm thick can be made easily by cold rolling. |
| Close dimensional tolerance is not possible. | Close dimensional tolerance (upto 0.002 mm) can be achieved. |
| Hot rolling is applicable to both ferrous and non-ferrous industries. | Cold rolling is equally applicable to both ferrous and non-ferrous industries. |
