HPM Grease Licensing Program
Testing required for HPM Grease Certification
The specification for HPM builds a robust grease that is applicable for a wide variety of applications. The specification requires basic requirements such as wear under pressure (4-Ball wear test) and other basic requirements for a grease (e.g., resistance to water washout, corrosion resistance to saltwater and resistance to oil separation). In addition, the HPM grease specification includes requirements for structural stability, ability for the grease to move at low temperature, compatibility with nitrile rubber which is a common seal material used for bearings.
The products are tested to the High-Performance Multiuse (HPM) Grease Program specification shown here. Download the HPM Specification details, which contains the test slate, test conditions, units, and limits.
The HPM+WR Specification includes three tests intended to demonstrate an increased level of performance over the HPM core Specification in wet or water wash environments. Water Washout (ASTM D1264) is the same test as used in the HPM core Specification but has a more restrictive limit. Water Spray Off (ASTM D4049) demonstrates a grease’s ability to resist water spray, while Wet Roll Stability (ASTM D8022) evaluates the effect of water on grease mechanical stability.
The HPM+CR Specification includes three tests intended to demonstrate improved corrosion resistance over the HPM core Specification in saltwater environments. Saltwater Rust (ASTM D5969) is similar to ASTM D1763 in the HPM core Specification but uses 10% synthetic sea water. Two versions of EMCOR Rust (ASTM D6138) evaluate corrosion protection in both 100% synthetic sea water and 0.5 N sodium chloride solution.
The HPM+HL Specification includes five tests intended to demonstrate improved load carrying capability over the HPM core Specification. Both the 4-Ball Wear (ASTM D2266) and 4-Ball EP (ASTM D2596) tests are the same tests as in the HPM core Specification, but have more challenging limits. Extreme Pressure Properties by SRV (ASTM D5706) and Fretting Wear by SRV (ASTM D7594) are included to further demonstrate improvement in these properties over the HPM core Specification. Fretting Wear by FAFNIR test (ASTM D4170) is also included with a tighter limit than the same test in the LB Specification.
The HPM+LT Specification includes three tests intended to demonstrate improved low temperature performance over the HPM core Specification. Low Temperature Torque of Ball Bearing Grease (ASTM D1478) is the same test as used in the HPM core Specification but is run at a lower temperature. Grease Mobility (U.S. Steel method) demonstrates grease resistance to flow at low temperatures, while Flow Pressure (by Kesternich method DIN 51805) is another way to look at flow at low temperatures.
Licensees must submit all test data with their product application to start the certification process.
HPM Webinar Series
NLGI's member companies created a dedicated webinar series specifically focused on the tests included in the new High-Performance Multiuse (HPM) grease specification. The series ran weekly from November 2020 to April 2021 with a new test from the HPM specification presented each week. A repository of this webinar series can be found in the Members’ Only area of the NLGI website here. Contact NLGI HQ at firstname.lastname@example.org or 816-524-2500 if you need login credentials.