Introduction to cold rolling
Cold rolling is a process by which metal is passed through rollers at temperatures below its recrystallization temperatures. The metal is compressed and squeezed, increasing the yield strength and hardness of the metal.
Cold rolling of metal strip is a special segment within the metalworking industry. The purpose of this process is to create thinner metal strips with a good dimensional accuracy and a dedicated surface quality for a variety of applications.
How does cold rolling work?
Strip sizes up to almost 2 meter wide and several millimeters thick can be the starting material. While on the other hand cold rolling mills can process and produce very small, few centimeters wide strip and approaching a 10 micron thick strip.
In contrast to hot rolling, the cold rolling process is done at ambient temperature. Usually forced cooling is applied to keep the metal temperature below the recrystallization temperature resulting in enhanced physical and surface properties.
The purpose of cold rolling lubrication oils
The best surface quality of the finished product is achieved by using high performance neat cold rolling oil for lubrication in the roll bite and cooling of the metal strip and work rolls.
Besides cooling, the cold rolling oil must lubricate and perform under extreme conditions:
- Local micro area pressures can be extremely high in the roll bite.
- The lubrication regime varies on micro scale and is typically in the boundary and mixed systems.
- Full hydrodynamic lubrication in the roll bite is not desired at all as it results in lack of grip. Low grip reduces strip control, increases speed variations and may result in deviating thicknesses, and therefore causes many surface defects.
The best lubrication oil for any cold rolling process
For a cold rolling oil to perform optimal in the boundary and mixed lubrication regime, a balanced cocktail of various additives in combination with ideally chosen base oils is required. The technical specialists of Q8Oils have the desired knowledge and expertise to offer the best product for each cold rolling process. The Q8 Bach R series is a range of high performance neat cold rolling oils.
Proven results with Q8 Bach R series cold rolling oils
We work closely together with customers to improve their cold rolling process with customized oil compositions. These efforts initially lead to an improved surface quality and reduced energy consumption of the mill engines as optimized lubrication reduces the friction.
Even more significant is the increased productivity achieved at various customers around the globe by reducing the amount of required passes through at reversing mills while still obtaining the demanded end thickness of the metal strip. This is only possible with the better lubricity allowing higher reductions at each pass.
Recently, a large Italian steel company switched to the newly developed Q8 Bach RSD cold rolling oil. Doing this, they managed to improve their productivity by reducing surface defects.