DIN ISO 14635-1:2025-04

This document specifies a test method based on a FZG four-square test machine to determine the relative load-carrying capacity of lubricating oils defined by the gear-surface damage known as scuffing. High surface temperatures due to high surface pressures and sliding velocities can initiate the breakdown of the lubricant films. This test method can be used to assess such lubricant breakdown under defined conditions of temperature, high sliding velocity and stepwise increased load. This standard differs from DIN ISO 14635-1:2006-05 and DIN ISO 14635-1 Corrigendum 1:2007-03 as follows: a) references to ISO 1328-1:1995 have been dated as this document uses an accuracy grade which is numerically different from the tolerance class in ISO 1328-1:2013; b) ISO 4287 is no longer referenced as it has been withdrawn and replaced by ISO 21920-2; c) ISO 4964 is no longer referenced as it has been withdrawn, and similar information can be found in ISO 18265; d) some bibliographic entries for standards which were withdrawn have been replaced, and changes have been made from dated to undated references; e) in subclause 5.2, the wording has been harmonized with the DIN ISO 14635 series; f) in Table 4, the lines "Direction of rotation" and "Test lubrication volume" have been added to conform to the information in the DIN ISO 14635 series. This document contains the English translation of the International Standard ISO 14635-1:2023, which has been prepared by Technical Committee ISO/TC 60 "Gears", Subcommittee SC 2 "Gear capacity calculation", the secretariat of which is held by DIN (Germany). The responsible German standardization committee is Working Committee NA 060-34-19 AA "Zahnradschmierung und Schmierstoffe" ("Gears lubrication and lubricants") of Technical Section "Drive technology" at DIN Standards Committee Mechanical Engineering (NAM).