ASTM Introduction

This test measures the load-carrying properties of a lubricant by rotating a steel pin at 290 rpm against two stationary V-blocks immersed in the lubricant sample. Load, in 250 foot pound increments, is applied to the V-blocks by a ratchet mechanism. The load is increased every minute until failure occurs as indicated by breakage of the shear pin or test pin, or inability to increase or maintain the load on the ratchet wheel. Results are reported as pounds with 4,500 being the maximum that can be detected. An extreme pressure fluid will maintain its lubricating properties as pressure and temperature increases.

This test measures the endurance or wear life of a lubricant. The test fluid is deposited on the pin and V-blocks and allowed to drain for 1 to 4 minutes. The steel pin is rotated at 290 rpm against two stationary V-blocks and a load of 300 foot pounds is applied. If after 60 minutes, there is no failure, the load is increased to 500 foot pounds. Failure is when the steady state torque is interrupted by a sharp increase or spike in the torque, breakage of the shear pin, or failure to maintain the load. Results are reported in minutes at load pounds.

This method is used to determine the tension at the surface of a liquid, thus providing an excellent indication of the spreading and penetration of a lubricant. A du Nouy precision tensiometer equiped with a (4-6 cm) platinum ring is used for this test. The ring is carefully placed on the surface of the liquid and the amount of force required to lift the ring and break the seal that forms between the open ring and the surface is measured as dynes per centimeter. Plain water has a surface tension of 72 dynes/cm; when a surfactant (surface active agent) is added to a liquid, the surface tension will drop to around 30 dynes/cm. Liquids that have a surface tension of 25 dynes/cm are usually excellent wetting and penetrating materials

This test is used to measure the ability of a fluid to displace water on a metal surface and then provide corrosion protection. Cold rolled steel panels, with surface prepared by sand blasting, are immersed in distilled water and then immersed in the test fluid just prior to being place in a static humidity chamber (25oC and 50% humidity) for one hour. The procedure is repeated but using the test fluid after a 10% level of water has been added and mixed with it. Results are reported as % visible corrosion for both the as is and the contaminated fluid.

The Kauri-Butanol Value (Kb Value) is an international, standardized measure of solvent power for a hydrocarbon solvent. The higher Kb value means that the solvent is more aggressive or active in the ability to dissolve certain materials. Mild solvents have low scores in the tens or twenties; powerful solvents like chlorinated materials have ratings that are in the low hundreds. In terms of the test itself, the Kb value of a chemical shows the maximin amount of hydrocarbon that can be added to a solution of kauri resin (a thick gum-like material) in butyl alcohol without causing cloudyness.

This test is used to measure the level of corrosion protection provided by a test fluid. Cold rolled steel panels, with surface prepared by sand blasting, are treated with the fluid by dipping or spraying, allowed to drain for 2 hours, then placed in the salt spray cabinet that contains a fog of 5% salt (NaCl) water solution at 35^oC (95^oF). Panels are left in the closed cabinet for the entire test period; independent labs typically use a 72-hour period.

To determine the penetrating ability of a fluid, a large nail is used to evaluate how quickly and completely the fluid will move up a vertical surface. A small quantity of the test fluid (60 ml) is added to a 600 ml tall beaker. A clean, sandblasted spike with a head of approximately 3/4” diameter, length 7” and shank diameter of 3/8” is placed head down in the center of the test fluid and the distance of the climb versus time is recorded. This is a comparative test so it is always better to run samples side by side.

The contact angle is the angle formed where the edge of a liquid stops flowing on a level surface. An instrument known as a Goniometer is used to measure the angle of contact. The lower the angle degree indicates how the liquid wants to keep flowing and penetrate any available area. Angles as low as zero degrees shows a liquid that will flow until absolutely flat on the surface.