The cold rolling process is normally used in the production of sheet metal in the manufacturing industry. The procedure includes a sheet of metal or other type of stock being placed between two rollers and squeezed out to the other side. This compresses the sheet and makes it very smooth and dimensionally accurate. Several sizes and types of cold rolling can be applied to sheet metal. There are, however, disadvantages to the process of cold rolling itself.
Contamination
In the hot rolling process, the metal is so hot that its heat takes care of any contamination problems. It burns away simple solid impurities, and can even boil away certain liquid impurities. Cold rolling does not have this advantage, so the parts of the machine that perform cold rolling must be cleaned, maintained and replaced frequently.
Energy Costs
It takes much more energy to roll a sheet of metal in cold rolling than it does for hot rolling. Heating up a sheet of metal makes the material more malleable, so when it is rolled between two rollers, it can form into a flat sheet much easier. A cold sheet of metal that is not heated up will be put through the rollers and have a higher amount of energy needed to push it through. Though there is less heating required, this is balanced out by the fact that it must be pushed through with more energy.
Shape and Formation
After the sheet is rolled in cold rolling, it is much more difficult to do anything else with it afterwards. It may have localized buckling due to stress below a yield point. The weight of a cold rolled sheet of metal is also disadvantageous because it is thin with relation to its weight. It cannot hold up to a workload as well as a hot rolled sheet of metal because its physical structure is not as strong.
Cost
The cold rolling process is an expensive one, especially compared to the process of hot rolling sheet metal. For example, since cold rolling requires that workers frequently clean parts like the rollers, cold rolling has extra costs for any supplies needed to clean the parts, downtime while the parts are being cleaned and labor costs for the worker who does the cleaning. Also, the additional energy needed in the cold rolling process adds cost to the final product.
