While no grease can truly be an “all-purpose” lubricant, aluminium complex grease is a valuable multifunctional, multipurpose product. Since they first came into the market in the 1960s, they have undergone numerous improvements, especially in terms of water resistance and thermal and mechanical stability. Callum Ford, National Marketing Manager at Lubrication Engineers (LE) South Africa, explains that idea applications include vehicle wheel bearings, manufacturing and assembly plants, steel mills, boat trailers, paper mills, and in the rubber, textile and agricultural and construction industries, among others.
“Aluminium complex greases are easy to pump at low temperatures because of their relatively low soap content and higher oil content,” he says. “They readily accept extreme pressure additives, plus all the usual rust and oxidation inhibitors and speciality additives. Formulations of specially selected oils and additives can also be made to produce sophisticated lubricants for moderately lower and higher temperature conditions. We categorise the mechanical or shear stability of aluminium complex greases in the range of ‘good to excellent’.”
LE’s aluminium complex greases include the company’s proprietary and exclusive wear-reducing additives. Ford says that the products also offer good “heat reversion characteristics”. This is the ability of the grease to revert to its normal consistency after it has been heated and cooled repeatedly.
Many industrial and automotive applications involve intermittent temperatures within a bearing that will approach or exceed the dropping point of the grease. Grease in such bearings may return to an ambient temperature periodically (for example, in a vehicle with disc brakes). If the grease in such an application does not maintain very nearly its initial consistency, it is obvious that the bearing is a candidate for failure. Aluminium complex greases, in addition to having a typical dropping point of 232°C to 246°C, also rate ‘excellent’ in heat reversion characteristics when compared to other multipurpose greases.
A well-formulated aluminium complex grease will also have excellent water resistance. Ford says that aluminium complex greases excel in resistance to both washing out of a bearing and being washed off a flat surface. “This resistance to water washout is very important where it is necessary to prevent lubricating grease from entering plant discharge water,” he says. “It also cuts down on lubricant consumption. The shear stability of aluminium complex grease is only moderately affected by water in the grease.”
LE’s aluminium complex greases include Monolec Industrial Lubricants (4700-4702) and Almaplex Industrial Lubricants (1274-1275). In addition, LE offers modified versions of aluminium complex greases, without EP additives, but containing the proper food grade oil to produce food-grade greases. These include LE’s Quinplex Food Machinery Lubricants (4023-4025), which meet the USDA and FDA H1 requirements.