In undisturbed penetration, the penetration value is measured without any disturbance. Grease Penetration Undisturbed penetration Penetration procedures to measure grease consistency Some grease suppliers use descriptions such as NLGI Number 1.5, which indicates that the grease is between NLGI Numbers 1 and 2. Penetration worked ASTM D217, DIN ISO 2137 in 0.1mm Very soft- just enough thickener to keep oil from running Therefore, grease penetration is calculated with the NLGI cone penetration chart using ASTM D217 Standard Test Methods for Cone Penetration of Lubricating Grease. Therefore, a higher penetration value indicates a softer lubricant.Īs per NLGI, greases are available in nine consistency grades ranging from fluid (NLGI 000) to a semi-fluid to a firm block (NLGI 6). In short, the cone will penetrate more into a soft grease. For example, a 28.5mm cone’s distance is a 285 penetration score (285x 0.1 mm). Thus, penetration is the depth, measured to an accuracy of 0.1 mm to which a standard cone sinks into the grease. Finally, the cone’s distance traveled into the grease is measured and reported as penetration in a tenth of a millimeter (0.1 mm). During this test, a double tapered cone is allowed to sink freely into a grease cup for 5 seconds at 25☌ under its weight. Therefore, lubricating grease consistency or NLGI grade is the first and foremost requirement. A grease consistency or penetration score indicates grease consistency or stiffness to help predict how it will migrate, stay, or flow in a typical grease application.

Viscosity and penetration test