BS-ISO-14635-3-2005.pdf

BRITISH STANDARD BS ISO 14635-3:2005 Gears FZG test procedures Part 3: FZG test method A/2, 8/50 for relative scuffing load-carrying capacity and wear characteristics of semifluid gear greases ICS 21.200 ? Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:43:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 14635-3:2005 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 17 January 2006 © BSI 17 January 2006 ISBN 0 580 47026 1 National foreword This British Standard reproduces verbatim ISO 14635-3:2005 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee MCE/5, Gears, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to v, a blank page, pages 1 to 19 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. DateComments Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:43:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Reference number ISO 14635-3:2005(E) INTERNATIONAL STANDARD ISO 14635-3 First edition 2005-09-15 Gears FZG test procedures Part 3: FZG test method A/2,8/50 for relative scuffing load-carrying capacity and wear characteristics of semifluid gear greases Engrenages Méthodes d'essai FZG Partie 3: Méthode FZG A/2,8/50 pour évaluer la capacité de charge au grippage et les caractéristiques d'usure des graisses d'engrenages semi-fluides BS ISO 14635-3:2005 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:43:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:43:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references. 1 3 Terms and definitions. 2 4 Brief description of method. 4 4.1 General. 4 4.2 Precision 4 5 Test materials 4 5.1 Test gears 4 5.2 Cleaning fluid 4 6 Apparatus 6 6.1 FZG spur gear test rig 6 6.2 Heating device. 7 6.3 Revolution counter. 7 6.4 Weight measurement 7 7 Preparation of apparatus . 8 8 Test procedure 9 9 Reporting of results 10 Annex A (informative) Test report 12 Annex B (informative) Additional test procedure for the investigation of extended wear characteristics of the lubricant . 13 Annex C (informative) Checklist for maintenance of FZG gear test rig 14 Bibliography. 19 BS ISO 14635-3:2005 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:43:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 14635-3 was prepared by Technical Committee ISO/TC 60, Gears, Subcommittee SC 2, Gear capacity calculation. ISO 14635 consists of the following parts, under the general title Gears FZG test procedures: Part 1: FZG test method A/8,3/90 for relative scuffing load-carrying capacity of oils Part 2: FZG step load test A10/16, 6R/120 for relative scuffing load-carrying capacity of high EP oils Part 3: FZG test method A/2,8/50 for relative scuffing load-carrying capacity and wear characteristics of semifluid gear greases BS ISO 14635-3:2005 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:43:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI v Introduction The types of gear failure which can be influenced by the lubricant are scuffing, low-speed wear and the gear fatigue phenomena known as micropitting and pitting. In the gear design process, these types of gear damage are taken into consideration by the use of specific lubricant and service-related characteristic values. In order to provide a reasonable estimate of performance in service, adequate lubricant test procedures are required. The FZG test procedures described in ISO 14635-1, ISO 14635-2 and ISO 14635-3 can be regarded as tools for the determination of relative scuffing performance of lubricants. Characteristic values can be introduced into the load-carrying capacity calculation of gears. ISO 14635-1 FZG test method, A/8,3/90 for relative scuffing load-carrying capacity of oils, is useful for the majority of applications in industrial and marine gears. ISO 14635-2, FZG step load test A10/16, 6R/120, is related to the relative scuffing load-carrying capacity of high EP oils as used, e.g. for the lubrication of automotive driveline components such as manual transmissions. ISO 14635-3 FZG test method A/2,8/50 describes a test procedure for the determination of the relative scuffing load-carrying capacity and wear characteristics of semi-fluid greases used for enclosed gear drives. Other FZG test procedures for the determination of low-speed wear, micropitting and pitting load capacity of gears are currently being considered for standardization. They could be added later to ISO 14635 as further parts. It has been assumed by the compilers of this test method that anyone using the method will either be fully trained and familiar with all normal engineering and laboratory practice, or will be under the direct supervision of such a person. It is the responsibility of the operator to ensure that all local legislative and statutory requirements are met. When the rig is running, there are long-loaded shafts and highly stressed test gears turning at high speed and precaution must be taken to protect personnel. It is also necessary to provide protection from noise. BS ISO 14635-3:2005 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:43:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI blank Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:43:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 1 Gears FZG test procedures Part 3: FZG test method A/2,8/50 for relative scuffing load-carrying capacity and wear characteristics of semifluid gear greases 1 Scope This part of ISO 14635 specifies a test method based on an FZG 1) four-square test machine for determining the relative load-carrying capacity of semi-fluid gear greases defined by the gear surface damage known as scuffing. This method is useful for evaluating the scuffing load capacity potential of semi-fluid gear greases of NLGI classes 0 to 000, typically used with highly stressed gearing for enclosed gear drives. It can only be applied to greases giving a sufficient lubricant flow in the test gear box of the FZG test machine. NOTE The test method is technically equivalent to DIN Fachbericht 74. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 1328-1, Cylindrical gears ISO system of accuracy Part 1: Definitions and allowable values of deviations relevant to corresponding flanks of gear teeth ISO 4287, Geometrical Product Specifications (GPS) Surface texture: Profile method Terms, definitions and surface texture parameters ISO 4964, Steel Hardness conversions ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method ISO 14635-1, Gears FZG test procedures Part 1: FZG test method A/8,3/90 for relative scuffing load-carrying capacity of oils ASTM D 235, Specification for Mineral Spirits (Petroleum Spirits) (Hydrocarbon Dry Cleaning Solvent) DIN 51818, Lubricants; consistency classification of lubricating greases; NLGI grades 1) FZG = Forschungsstelle für Zahnräder und Getriebebau, Technische Universität München (Gear Research Centre, Technical University, Munich). BS ISO 14635-3:2005 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:43:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 2 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 scuffing particularly severe form of gear tooth surface damage in which seizure or welding together of areas of tooth surface occurs, owing to insufficient or breakdown of lubricant film between the contacting tooth flanks of mating gears, typically caused by a combination of high temperature, high pressure and other factors NOTE 1 Scuffing is most likely when surface velocities are high. It can also occur at relatively low sliding velocities when tooth surface pressures are high enough either generally or, because of uneven surface geometry and loading, in discrete areas. NOTE 2 Care should be taken that scuffing does not occur and is polished away before ending the running time at the higher load stages. 3.2 wear continuous removal of material occurring when two surfaces roll and slide against one another 3.3 scuffing load-carrying capacity of a lubricant maximum load which can be sustained under a defined set of conditions 3.4 FZG test condition A/2,8/50 test condition where A is the particular tooth form of the test gears, according to Table 1, 2.8 is the speed at the pitch circle in metres per second (m/s), and 50 is the initial lubricant temperature in degrees Celsius, from load stage 4 onward in the lubricant sump 3.5 failure load stage load stage reached when the summed total width of scuffing damage on the active flank area of the 16 pinion teeth exceeds one gear tooth width, i.e. 20 mm. NOTE For examples of failure, see Figure 1. Examples of tooth flank changes due to continuous wear are given in Figure 2. Continuous wear is not a failure criteria for the test. BS ISO 14635-3:2005 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:43:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 3 a) Marks, no failure b) Marks, no failure c) Approx. 5 mm failure marks d) Approx. 15 mm failure marks e) 20 mm failure marks f) Approx. 2 mm failure marks g) Approx. 6 mm failure marks h) 20 mm failure marks NOTE This figure describes the typical pinion tooth flank changes occurring in FZG scuffing type tests. Changes in the original surface condition (criss-cross grinding) can be described by their physical appearance. One and the same type of flank damage can be described in different places in the world by using different terminology (e.g. “scuffing”, “scoring” and “severe wear”). In order to avoid misinterpretation of the pinion tooth flank changes occurring during the test, typical examples of non-failure and failure are given. Figure 1 FZG A-type gear tooth face changes (flank damages) BS ISO 14635-3:2005 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:43:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 4 a) Light wear b) Medium wear c) Severe wear Figure 2 FZG A-type gear tooth flank changes due to continuous wear 4 Brief description of method 4.1 General A set of test gears as defined in Clause 5, Tables 1 and 2, weighed to the nearest 0,001 g before the test, is run with the test lubricant at constant speed for a fixed number of revolutions in dip lubrication mode. Loading of the gear teeth is increased in the steps outlined in Table 3. Beginning with load stage 5, the initial lubricant temperature is controlled between (50 ± 3) °C. During the test run of each load stage, the lubricant temperature is allowed to rise freely. After load stage 4, the weight loss of the gear set is determined to the nearest 0,001 g and the pinion tooth flanks are inspected for surface damage. For each subsequent load stage the pinion tooth flanks are inspected for surface damage at the end of each load stage and any changes in appearance are noted. A test is considered complete when either the failure criteria has been met or when load stage 12 is run without meeting the failure criteria. If load stage 12 is reached without meeting the failure criteria, the gear set weight loss is determined to the nearest 0,001 g. 4.2 Precision Values of repeatability, r, and reproducibility, R, as defined in ISO 5725-2, are not valid for this test procedure. However, experience suggests that similar methods (see ISO 14635-1) are expected to be representative. Values for ISO 14635-1 are indicated below. r = 1 load stage R = 2 load stages NOTE The above precision results apply to the range of failure load stages 5 to 12. 5 Test materials 5.1 Test gears A pair of type “A” gears with a specification according to Table 1 and Table 2 shall be used for testing. Each pair of test gears may be used twice for testing, utilizing both tooth flanks as load-carrying flanks. 5.2 Cleaning fluid Petroleum spirits conforming to ASTM D 235 shall be used. BS ISO 14635-3:2005 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:43:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 5 Table 1 Details of FZG test gears type A Dimension Symbol Numeric