DIN Standards Committee Mechanical Engineering
Calculation of load capacity of cylindrical gears - Part 16: Determination of the micro-pitting load-carrying capacity of lubricants using FZG-test-method GT-C/8,3/90
Abstract
Limits in the load-carrying capacity of gears known today, which can be influenced by lubricants, are scuffing (scoring and scuffing), low-speed wear and the manifestations of tooth flank fatigue such as micropitting and pitting. Appropriate lubricant test procedures are necessary for an exact lubricant selection based on the application. These can be regarded as tools for the determination of characteristic lubricant values to be used in the calculation of the load-carrying capacity of gears. FZG test methods regarding the scuffing load-carrying capacity are described in the DIN ISO 14635 series of standards and the FZG test method regarding the determination of the slow speed wear carrying capacity of lubricants is described in DIN 3990-17. FZG test methods for the load capacity limits regarding micropitting and pitting (in progress) are described in the DIN 3990 series of standards. This part of the standard describes the current status of the FZG micropitting test developed within the scope of the FVA research project No. 54/I-IV. By using the GT-C/8,3/90 micropitting test, the influence of lubricants and their lubricant additives on the formation of micropitting can be quantitatively determined for a wide range of applications, e.g. vehicle, industrial, wind power and marine transmissions. The micropitting test differentiates lubricants with regard to their micropitting load-carrying capacity and allows the selection of a sufficiently load-carrying lubricant with regard to micropitting formation. This document specifies requirements for a test method used to determine the micropitting load-carrying capacity of lubricating oils for gear drives, in particular lubricating oils of category CLP according to DIN 51517-3, on an FZG gear test rig. The test method can be applied to all lubricating oils which have a sufficient load-carrying capacity in the test according to DIN ISO 14635-1 or ISO 14635-1. The failure load stage achieved in the DIN ISO 14635-1 or ISO 14635-1 test procedure can be used as a reference value for the highest load without increased risk of scuffing in the test procedure described here. The test procedure specified here is mainly based on the micropitting test described in the FVA Information Sheet No. 54/7 [4] and is only applicable to liquid lubricants. On the basis of the information given in FVA Information Sheet No. 54/7 [4], the test conditions, in particular the pitch line velocity and the lubricant injection temperature, can be modified according to the operating conditions for the application considered. These test modifications are explicitly not part of this standard. The accuracy data defined here apply only to the test methods specified in this document; any modifications to these test methods are explicitly not covered by this document.
Begin
2026-03-27
Planned document number
DIN 3990-16
Project number
06004641
Responsible national committee
NA 060-34-19 AA - Gears lubrication and lubricants
