|Extreme Pressure Properties* of Krytox® Greases
|Load Wear Index
|Weld Piont, kg
* ASTM 02596, Measurement of Extreme Pressure Properties of Lubricating Grease, Four Ball Method.
** These samples maxed the load limit of the test apparatus, and a load wear index cannot be determined.
Some applications require a grease that is stiff and does not fall back easily into the bearing races. Often, these systems run at higher speeds. Harder NLGI Grade 3 Krytox® greases are recommended for these applications.
Drive chains, such as roller chains, require lubrication. They are often exposed to the atmosphere and require a lubricant with anticorrosion properties. The lubricant must also have good adhesion and the ability to wet the chain links-characteristics provided by Krytox® . Often, EP additives are included to reduce chain wear caused by oscillating and sliding friction.
Because of its thermal stability and nonoxidizing characteristics, Krytox® is a natural high-temperature lubricant. Krytox® grease has a drop point of 325°C (617°F). Dropping point (thickener melting point) test results can be confusing or misinterpreted with PTFE thickened greases. Testing shows that some oil separation occurs at about 210°C (410°F), and this has sometimes been reported as the dropping point. Krytox® greases are available with useful temperature ranges up to 288°C (550°F) for continuous use. Special thickener formulations have been blended to give useful lubrication up to 371-399°C (700-750°F) with spikes at 427°C (800°F) or higher with more frequent relubrication.
Low-Temperature Greases Krytox® grades formulated with low viscosity oils can be used at temperatures as low as -57°C (-700P).
Krytox® is used in all types of valves to lubricate moving parts, seal connections, and packing and to protect surfaces from corrosion and degradation. Krytox® lubricates the valve packing and allows it to expand and contract without binding, reducing leakage around the stem. Valves operate more smoothly because Krytox® eliminates sticking and jumping. It is used on safety relief valves to prevent sticking and over pressurization.
Krytox® lubricants for seals and gaskets material do not cause cracking or swelling and are compatible with all plastic and synthetic rubber material.
Mechanical Seal Barrier Fluids
Mechanical seals are used in many aggressive chemical reactions. Conventional barrier fluids can violently react with some chemicals. Krytox® can be used as a seal barrier fluid in reactive chemical systems, without fear of reaction occurring between the chemicals and the barrier fluid. Chlorination, fluorination, bromination, nitration, and other aggressive reactions can safely be sealed inside the reaction vessel.
A special low vapor pressure Krytox® oil is used to formulate a grease for high-vacuum applications. It is also useful for sealing laboratory glassware connections and as a thread lubricant/sealant.
Krytox® vacuum pump fluids are used in applications where conventional vacuum pump oils cause safety, waste disposal, and maintenance problems. They are nonflammable and reduce the chance of fire in pumps. They are nonreactive and safe to use in oxygen systems. They can replace any competitive PFPE fluid as well as any other type of vacuum fluid. Krytox® fluids do not contain acetal groups, which are susceptible to attack by Lewis acids. This gives Krytox® superior stability as a vacuum pump fluid. Krytox® vacuum fluids are precisely distilled to provide low vapor pressures and give superior performance. In addition, Krytox® fluids are recyclable.
Food Grade Lubricants
Krytox® greases have a USDA H-2 rating when Nuclear Industry Greases. Many parts of a nuclear power plant are exposed to high heat and humidity or are difficult to access for regreasing. The use of Krytox® with its longer life and high-temperature capabilities allows these parts to run without relubrication for the full fuel cycle. Tests have shown that Krytox® can be used in radiation up to 107 rads with no breakdown.used in food processing plants.
The Krytox® 240 grease series meets a variety of military and industrial specifications. Some of the more common MIL specs and Krytox® products are:
|MIL-PRF-27617 Type I
||240AZ NLGI 1
|MIL-PRF-27617 Type II
|MIL-PRF-27617 Type III
Grease Mechanical Stability Krytox® greases have excellent mechanical stability in bearings. They do not break down under mechanical stress and lose their ability to hold oil. The greases were mixed in a grease worker for 60, 10,000, and 100,000 strokes and tested for changes in hardness. All greases tested had changes of less than 30 points on the NLGI penetration scale and were within 1/2 grade of their original starting point. Roll stability tests were performed according to ASTM D1831 for 2 hr with the 4500-lbf reference load. The penetration change was minor and was within 1/2 grade of the original starting point.
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