Cold rolling is the process by which metal is passed through rolls at a temperature below its recrystallization temperature. The metal is compressed and squeezed, increasing the yield strength and hardness of the metal.
Cold rolling of metal strip is a special segment in the metal processing industry. The purpose of the process is to manufacture thinner metal strips with good dimensional accuracy and specialized surface quality for various applications.
How does cold rolling work?
The starting material can be strips up to 2 meters wide and a few millimeters thick. On the other hand, cold rolling mills can process and produce very small strips of a few centimeters wide and strips approaching 10 microns thick.
In contrast to hot rolling, the cold rolling process is done at ambient temperature. Forced cooling is often employed to keep the metal temperature below the recrystallization temperature, thereby enhancing physical and surface properties.
The use of cold rolling lubricants
The roll nip and cooling of the metal strip and work rolls are lubricated with high performance pure cold rolling oil for optimum finished surface quality.
In addition to cooling, cold rolling oils must also lubricate under extreme conditions:
- Localized microzone pressures in the roll nip can be very high.
- Lubrication regimes vary on a microscopic scale, often in boundary and mixed systems.
- Full hydrodynamic lubrication in the rolling bite is not required at all as it causes a lack of grip. Low clamping forces reduce strip control, increase speed variations and can cause thickness deviations, which can lead to numerous surface defects.
The Best Lubricant for Any Cold Rolling Process
For cold rolling oils to perform optimally in boundary and mixed lubrication regimes, a balanced mixture of various additives combined with an ideally selected base oil is required. HDM's technical experts have the knowledge and expertise needed to deliver the best possible product for each cold rolling process. The HDM range is a range of high performance pure cold rolling oils.
Proven Results Using HDM Series Cold Rolling Oils
We work closely with our customers to improve their cold rolling processes using custom oil compositions. These efforts initially improved the surface quality and energy consumption of mill engines due to optimized lubrication reducing friction.
What's more, various customers around the world have achieved productivity gains by reducing the required throughput of reversing mills while still achieving the desired final thickness of the metal strip. This is only possible if better lubricity allows higher reductions per pass.
Recently, a large Italian steel company switched to the newly developed Q8 Bach RSD cold rolling oil. By doing so, they managed to increase productivity by reducing surface defects.
