The transmission of power in many automotive and industrial applications is accomplished through the use of geared systems. At higher operating speeds it is well known that the lubricant/additive system can be a significant factor in preventing scuffing (adhesive wear) damage to gears. This test method is used to screen the scuffing load capacity of oils used to lubricate spur and helical (parallel axis) gear units.

The test method is limited by the capabilities of the equipment (test rig and gears), and the performance observed may not directly relate to scuffing performance observed with spiral bevel on hypoid gearing. It is also limited to discriminating between oils with mild EP additives or less. Lubricants containing higher levels of additives, that is, those meeting the requirements of API GL4 or GL5, generally exceed the maximum load capacity of the test rig and, therefore, cannot be distinguished for their scuffing capabilities by this test method.

1.1 This test method, the Forschungstelle für Záhnräder und Getriebebau (Research Site for Gears and Transmissions) Visual Method, commonly referred to as the FZG Visual Method, is intended to measure the scuffing load capacity of oils used to lubricate hardened steel gears. Scoring, a form of abrasive wear, is also included as a failure criteria in this test method. It is primarily used to assess the resistance to scuffing of mild additive treated oils such as industrial gear oils, transmission fluids, and hydraulic fluids. High EP type oils, for example, those oils meeting the requirements of API GL-4 and GL-5, generally exceed the capacity of the test rig and, therefore, cannot be differentiated with this test method.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific safety information, see Section 7, Section 8, 9.2, 9.3.1, and Annex A1.