ELGI Groups Develop Grease Tests


BARCELONA, Spain – Scale and wear particles are the most common sources of contaminants in greases, along with burned soap, dirt and sand, a working group of the European Lubricating Grease Institute reported last week at the ELGI Annual General Meeting.

The Grease Particle Evaluation Working Group reported that it continues to progress in its effort to develop a way of measuring grease contamination. Other ELGI working groups are developing tests for rheological properties and performance of bio-based greases.

Afton Chemicals Joseph Kaperick reported on the efforts of the Grease Particle Evaluation Working Group to identify reliable tests to characterize contaminants in greases. The most common contaminants are scale and wear particles from production equipment, as well as burned soap, dirt and sand. We have found that the most useful criteria are the number, size and hardness of the particles, he said.

Kaperick then reported on the progress of two test methods being considered by the group: the Hegman Gage used by the paint industry and ASTM D 1404 for estimating particle content in grease. Round robin tests are being run to develop repeatable methods for rating the potential of particles to damage surfaces. We are also seeking feedback from original equipment manufacturers on what types of data are important to them, he concluded.

Olav Honegger of Shell Global Solutions reviewed efforts by the Test Methods and Rheology Working Group to establish valid, recognized procedures to measure the rheological properties of grease. Our first task is to identify a reference grease, he said, noting that one goal is to combine ELGI and NLGI requirements into a single document. Honegger also said that ISOs TC28 working group will hold its first meeting in June to assess rheology testing of greases.

The ELGI working group is also looking into methods to measure rheology in centralized lubrication systems, which differs significantly from that in individual components. Finally, they are running round robin tests to compare various copper corrosion tests. The different DIN and ASTM methods all generate different results, Hoeger said. We need a way to correlate the results. DIN is a German Institute for Standardization standard.

The Biobased Greases Working Group is investigating tests that accurately measure the performance of these products. Many performance standards are based on petroleum base oils, said George Dodos of Eldons, and they dont always correlate to biobased greases. In particular, the group is studying methods to determine the oxidative stability and low-temperature properties of these greases. Round robin tests are underway to identify an oxidative stability test, and the group has tentatively selected a low-temperature test, but more study is needed.

Finally, consultant Lou Honory reported that the Railway Lubricants Working Group is focusing on European railways because they use different types of greases than in the United States. Trainborne and trackside greases require vastly different properties, he said, and the group is aiming to finalize specifications and approval processes for these greases.

Andre Adam of Fragol, reporting on the Joint Food-grade Lubricants Work Group, noted that the committees efforts are largely aimed at political rather than technical issues. Some companies are sending the wrong messages to the market, he said. For example, one company touts its grease as being edible. This only serves to focus more attention on the potential safety of grease in food production equipment, he noted.

Another challenge involves the safety of mineral oil hydrocarbons. We are focusing our efforts on informing lawmakers about food-grade lubricants, their production and their safety, Adam said. We must prove that mineral oil hydrocarbons pose no safety risks.

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