What is grease

Lubricating greases are pasty lubricants that consist of a lubricating oil and a thickener (soap, bentonite, polyureas, PTFE ...).

Classification of lubricating greases

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after base oil

  • Alkylated naphthalenes (AN)
  • Chlorotrifluoroethylene (CTFE)
  • Ester oils
  • Mineral oils
  • Multialkylated Cyclopentanes (MAC)
  • Polyalphaolefins (PAO)
  • Polyphenyl ether (PPE)
  • Polyglycol oils
  • Perfluorinated polyether oils (PFPE)
  • Silicone oils

after thickener

  • Aluminum soap, aluminum complex soap
  • Barium soap, barium complex soap
  • Calcium soap, calcium complex soap
  • Lithium soap, lithium complex soap
  • Sodium soap, sodium complex soap
  • PTFE
  • Inorganic thickener (bentonite)
  • Polyurea
  • Silica

according to consistency class

This is indicated in the consistency index. It is measured with a "penetrometer". The penetration depth of a cone allows it to be assigned to a consistency class. A distinction is made between consistencies from 000 (fluent) to 6 (hard). The consistency index is also specified as the NLGI class according to DIN 51818 and can be specified in rest or milled penetration, with the consistency measurement according to DIN ISO 2137 the grease being milled before measuring in order to imitate the stress in a bearing. Classifications:

Consistency class worked penetration (in units, where one unit corresponds to approx. 0.1 mm)
000: 445 to 475
00: 400 to 430
0: 355 to 385
1: 310 to 340
2: 265-295
3: 220 to 250
4: 175-205
5: 130 to 160
6: 85 to 115 (rest penetration)

according to the object to be lubricated

  • Rolling bearing greases
  • Sealing grease
  • water-resistant pump grease

after application

  • Normal fats
  • Multipurpose greases
  • EP greases
  • High temperature greases

Applications for lubricating greases

Lubricating greases are used to prevent mechanical wear and tear caused by friction. If, for example, a machine or a bearing is operated without lubricating grease or oil, so-called hot runners occur. This means that the metal parts hitting one another get hot, which can lead to a blockage. The grease creates a film between the components and prevents direct contact between the moving surfaces. The friction is greatly reduced and the machine or the bearing can run more easily and generates less frictional heat.

Categories: Tribology | Lubricant