High-Temperature Grease Guide Professionalمنذ 3 أشهر - Multimedia - Saïda - 44 الآراء
A reasonable starting point for selecting a high temperature grease is to consider the nature of the temperatures and the causes of product degradation. Greases could be divided by temperatures along the lines in Table 1.
There is general correlation between a grease’s useful temperature range and the expected price per pound. For instance, a fluorinated hydrocarbon-based (type of synthetic oil) grease may work effectively as high as 570oF (300oC) in space applications but may also cost hundreds of dollars per pound.
The grease’s long-term behavior is influenced by the causes of degradation, three of which are particularly important: mechanical (shear and stress) stability, oxidative stability and thermal stability. Oxidative and thermal stresses are interrelated. High-temperature applications will generally degrade the grease through thermal stress, in conjunction with oxidative failure occurring if the product is in contact with air. This is similar to what is to be expected with most industrial oil-lubricated applications.
Large production facilities have a variety of grease-lubricated equipment, ranging from steady-state applications to applications that vary significantly in speed and load, and operate in aggressive (wet or dusty) environments.
If machine designers address equipment lubrication needs based strictly on a dynamic loading requirement, they might have to specify a wide variety of greases to meet the many existing needs. In this approach, the added system complexity would likely increase the cost and the risk of failure due to misapplication and cross-contamination.
To maximize grease lubrication effectiveness, minimize cost and minimize risk of application-induced failure, lubricant manufacturers have made an effort to formulate greases that cover a variety of applications. These greases range from slow to high speeds, and from low to high loads, in an effort to provide a single product to meet a multitude of requirements. The result is general purpose grease.