Minimum Quantity Lubrication for Cold Mills

The Minimum Quantity Lubrication (MQL) system is a next-generation roll-gap lubrication solution developed by Primetals Technologies, designed to enhance lubrication efficiency in the steel industry. MQL applies neat rolling oil atomized with air onto the surfaces of the work rolls, ensuring precise lubrication. Efficient lubrication is crucial for maintaining the quality of rolled products and minimizing operational costs, and MQL addresses these challenges effectively. By providing precise lubrication, MQL reduces oil consumption and minimizes environmental impact, offering a sustainable approach to steel production.

Minimum Quantity Lubrication (MQL) is a cutting-edge solution designed to optimize the lubrication process in cold mills. This advanced technology applies neat rolling oil atomized with air directly onto the surfaces of the work rolls, creating a precise oil layer with a defined thickness. By replacing conventional roll-gap lubrication systems, such as emulsion lubrication, MQL significantly improves friction conditions between the work roll and the strip. Delivering the exact amount of oil required for adequate roll gap lubrication, MQL ensures superior lubrication efficiency, reduces lubricant usage, leads to substantial cost savings, and minimizes environmental impact.

MQL allows for flexible control of the oil layer thickness, enabling operators to quickly adjust the lubrication regime from one coil to the next. This flexibility is crucial for adapting to varying lubrication demands across different mill types and stands, ensuring optimal friction conditions throughout the rolling process. The technology can be seamlessly integrated with existing emulsion lubrication systems, maintaining cooling efficiency by applying emulsion exclusively on the exit side of each stand. This separation prevents interference between the emulsion flow and the oil mist on the entry side, thereby optimizing both lubrication and cooling. Particularly for the production of high-silicon non-grain-oriented (NGO) steel, where temperature control is vital for stable rolling, MQL offers new possibilities in Si-steel processing. It prevents unwanted cooling of the strip through the emulsion while ensuring excellent lubrication required for thin-gauge rolling.

Delivered as a mechatronic package, MQL is ready for integration into any existing mill setup, including batch and continuous tandem mills, skin pass mills, and double cold reduction mills. The package includes two spray bars per stand, an oil supply, and a process unit comprising mechanical and electrical components that require a pressurized air supply for operation. Pre-defined interfaces ensure easy integration into existing plant automation systems. Primetals Technologies also offers a mobile MQL test unit and a set of spray bars for temporary installations, allowing steel producers to evaluate the benefits before committing to a complete industrial solution. With robust and maintenance-friendly spray bars featuring quickly exchangeable oil/air nozzles, MQL minimizes downtime and maintenance efforts.

By utilizing MQL, steel mills can achieve reduced rolling forces, decreased strip wear, and extended work roll lifetime, all while maintaining high product quality and reducing operational costs. Currently, two European tandem cold mills and one European reversing mill benefit from the installation of MQL, demonstrating its effectiveness and value in modern steel production.

Benefits of Minimum Quantity Lubrication from Primetals Technologies

• Achieve optimal lubrication with minimal oil usage, ensuring consistent lubrication and enhancing the quality of rolled products
• Reduces lubricant consumption, lowering operational expenses by up to 10%
• Minimize oil waste, supporting sustainable manufacturing practices, and reducing environmental impact
• Ensure consistent lubrication, enhancing the quality of rolled products and extending the product mix
• Integrate with existing cold mill systems for straightforward implementation, enabling flexible and product-specific lubrication strategies
• Up to 20% roll-force reduction: reduces rolling forces, extending work roll lifetime by up to 10% and improving strip surface cleanliness.
• Extension of reduction capability: allows for higher strength grades and increased strip width or reductions, optimizing mill performance.