Extreme pressure cutting oil additives work to reduce tool wear. They react with the metal surface to create a solid protective layer, reducing friction even in the most severe metalworking conditions. EP cutting oil additives may include polymeric esters, organophosphorus, sulfur, soap esters, and chlorinated paraffin. The additives are thermally activated at various temperatures because metalworking is exposed to a wide range of surface temperatures.
Types of Cutting Oil Additives
Sulfur is used in cutting oil additives that are suitable for the more severe cutting operations because it is activated at a higher temperature above 600-1,000 degrees Celsius. Sulfur may cause a reaction with yellow metals, producing dark sulfide stains. Choosing sulfur that is active or inactive and light or dark colored will depend on the metal substrates with which you are working. Sulfurized esters are multi-functional in nature, which provides valuable flexibility when formulating new combinations of lubricity and EP cutting oil additives.
Phosphorus overlaps slightly with sulfur, activating at around 200-600 degrees Celsius. A number of formulators have raised concerns regarding the decomposition of phosphorus in water and the potential it has for the creation of corrosive acids.
Overbased sulfonates are not heat-activated and work differently than other extreme pressure additives. It introduces a carbonated film between the workpiece and the tool. They are used synergistically with other EP agents that are chemically reactive, including sulfur or phosphorus.
Depending on your application, cutting oils may contain a wide variety of additives including rust inhibitors, corrosion inhibitors, biocides, lubricity, and emulsifiers.
