1、 Reference numberISO 4666-2:2008(E)ISO 2008INTERNATIONAL STANDARD ISO4666-2Second edition2008-11-01Rubber, vulcanized Determination of temperature rise and resistance to fatigue in flexometer testing Part 2: Rotary flexometer Caoutchouc vulcanis Dtermination de llvation de temprature et de la rsista
2、nce la fatigue dans les essais aux flexomtres Partie 2: Flexomtre rotation ISO 4666-2:2008(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded ar
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5、ating to it is found, please inform the Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT ISO 2008 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including ph
6、otocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in S
7、witzerland ii ISO 2008 All rights reservedISO 4666-2:2008(E) ISO 2008 All rights reserved iiiContents Page Foreword iv 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Principle. 2 5 Test pieces 2 6 Apparatus 2 6.1 Rotary flexometer (see Figures 1 and 2) 2 6.2 Measuring gauge 4 6.
8、3 Temperature-measurement device . 4 6.4 Timer 4 7 Procedure 4 7.1 Preparation 4 7.2 Test operation . 4 7.2.1 General. 4 7.2.2 Measurement of temperature rise . 4 7.2.3 Determination of resistance to fatigue breakdown. 4 8 Test conditions . 5 8.1 General. 5 8.2 Measurement of temperature rise . 5 8.
9、3 Determination of resistance to fatigue breakdown. 5 9 Evaluation of test data 6 9.1 Temperature rise. 6 9.2 Resistance to fatigue breakdown 6 9.2.1 Fatigue life . 6 9.2.2 Fatigue-life curves 6 10 Test report . 8 Bibliography . 9 ISO 4666-2:2008(E) iv ISO 2008 All rights reservedForeword ISO (the I
10、nternational 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
11、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 electrotechnica
12、l 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 bod
13、ies 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
14、 or all such patent rights. ISO 4666-2 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee SC 2, Testing and analysis. This second edition cancels and replaces the first edition (ISO 4666-2:1982), of which it constitues a minor revision. The main change is the rep
15、lacement of ISO 4648 by ISO 23529 in Clause 2 and in 6.2. ISO 4666 consists of the following parts, under the general title Rubber, vulcanized Determination of temperature rise and resistance to fatigue in flexometer testing: Part 1: Basic principles Part 2: Rotary flexometer Part 3: Compression fle
16、xometer Part 4: Constant-stress flexometer INTERNATIONAL STANDARD ISO 4666-2:2008(E) ISO 2008 All rights reserved 1Rubber, vulcanized Determination of temperature rise and resistance to fatigue in flexometer testing Part 2: Rotary flexometer WARNING Persons using this part of ISO 4666 should be fami
17、liar with normal laboratory practice. This part of ISO 4666 does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditi
18、ons. CAUTION Certain procedures specified in this part of ISO 4666 may involve the use or generation of substances, or the generation of waste, that could constitute a local environmental hazard. Reference should be made to appropriate documentation on safe handling and disposal after use. 1 Scope T
19、his part of ISO 4666 specifies a rotary flexometer test for the determination of the temperature rise and resistance to fatigue of vulcanized rubbers under rotary shear loading. It allows the use of all four types of test conditions described in ISO 4666-1. It gives directions for carrying out measu
20、rements which make possible predictions regarding the durability of rubbers in finished articles (tyres, bearings, supports, V-belts, cable pulley insert rings and similar products subject to dynamic flexing in service). However, owing to the wide variations in service conditions, no simple correlat
21、ion between the accelerated tests described in this part of ISO 4666 and service performance can be assumed. 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,
22、 the latest edition of the referenced document (including any amendments) applies. ISO 4666-1, Rubber, vulcanized Determination of temperature rise and resistance to fatigue in flexometer testing Part 1: Basic principles ISO 23529, Rubber General procedures for preparing and conditioning test pieces
23、 for physical test methods 3 Terms and definitions For definitions of the terms and concepts used in connection with this test and in evaluating the test results, see ISO 4666-1. ISO 4666-2:2008(E) 2 ISO 2008 All rights reserved4 Principle A cylindrical test piece is compressed axially to a predeter
24、mined stress or strain (pre-stress or pre-strain) between two chuck plates. One of the chuck plates is mounted on a freely rotating shaft while the other plate is mounted on a shaft which is driven by a motor. The shafts are displaced laterally relative to each other by a predetermined amount or by
25、means of a predetermined force. The eccentricity of the two rotating plates produces a flexing of the rotating test piece, while it is under compression, resulting in a rise in temperature and ultimately fatigue breakdown. The rise in temperature is determined at the centre of the test piece by mean
26、s of a needle probe. The fatigue life is also determined. 5 Test pieces For general guidance as to number, preparation and conditioning of test pieces, see ISO 4666-1. The test pieces shall be cylinders of height equal to their diameter. The dimensions shall be either 20 mm 0,2 mm or 38 mm 0,4 mm. T
27、he smaller test piece is preferred because it is usually more uniform in degree of vulcanization throughout the whole mass. If test pieces are prepared by vulcanization in moulds, it is recommended that the mould cavities have a diameter and depth of 20,2 mm 0,05 mm or 38,2 mm 0,05 mm in order to al
28、low for thermal shrinkage after vulcanization. If test pieces are prepared from finished parts by cutting, it is recommended that the circular die used for this purpose has an inside diameter of 20 mm 0,03 mm or 38 mm 0,03 mm. 6 Apparatus 6.1 Rotary flexometer (see Figures 1 and 2) The schematic ill
29、ustration in Figure 1 shows the important parts of the flexometer. The cylindrical test piece acts as a friction clutch between two chuck plates mounted on parallel shafts such that they can be rotated. The shaft carrying the right-hand chuck plate (see Figure 1) shall be mounted on a movable bearin
30、g so that almost frictionless movement in the axial direction is possible. This is in order that the test piece can be subjected to axial compression by displacing the movable chuck plate by a predetermined amount (testing under constant pre-strain) or through the action of a predetermined force (te
31、sting under constant pre-stress), for example by means of a compression spring. The movable bearing shall also be capable of being displaced transversely with respect to the axis of the test piece. This displacement can be obtained by movement of the bearing carrier or by means of a cross support ar
32、rangement. In this manner, a transverse deformation is imposed upon the test piece. The deflection can be by a predetermined amount (testing under constant cyclic strain) or under the action of a predetermined force (testing under constant cyclic stress). The left-hand chuck plate shall be driven by
33、 a motor at a rotational frequency of 14,6 Hz 0,1 Hz or 25,0 Hz 0,2 Hz. The test piece transmits the rotation from the driven chuck plate to the displaceable chuck plate. The rotation and simultaneous deflection subject the test piece to a sinusoidal form of shear deformation. Suitable devices such
34、as dial gauges and electronic transducers shall be incorporated in order to determine all the deformations and loadings of the test piece. The devices for measuring the deformations shall have a precision of at least 0,01 mm. The precision of the force-measuring devices shall be at least 0,1 N. The
35、use of chart recorders for recording the transverse force or the transverse displacement is recommended. The measuring devices shall be mounted so that their pressure acts against the loading as shown in Figure 1. The chuck plates shall be made of steel. Caps made of plastics or other heat-insulatin
36、g materials having a conductivity of not more than 0,28 W/(mK) can be placed over these for heat-generation tests if considered necessary. The caps shall have a thickness of 10,0 mm 0,2 mm and shall lie in close contact with the metal plates over their entire surface. As an alternative to caps, disc
37、s of heat-insulating material can be placed immediately behind the chuck plates. ISO 4666-2:2008(E) ISO 2008 All rights reserved 3Key 1 motor 5 displacement transducer 8 force transducers 2 fixed bearing 6 compression spring 9 movable bearing 3 chuck plates 7 intermediate piece 10 dial gauge 4 weigh
38、t for transverse loading Figure 1 Rotary flexometer before application of force Key 1 test piece Figure 2 Rotary flexometer after application of force To facilitate location of the cylindrical test piece between the chuck plates or caps, and in order to avoid sideways displacement during the test, t
39、he chuck plates and caps shall be provided with a centrally located recess to receive the test piece. The recess shall have the following dimensions: for small cylinders: diameter 20,2 mm 0,03 mm, depth 0,7 mm 0,03 mm; for large cylinders: diameter 38,4 mm 0,05 mm, depth 1,0 mm 0,05 mm. ISO 4666-2:2
40、008(E) 4 ISO 2008 All rights reserved6.2 Measuring gauge The gauge for measuring the height and diameter of the test pieces shall conform to the requirements of ISO 23529. A dial gauge having a circular foot probe of diameter 10 mm and exerting a pressure of 22 kPa 5 kPa is suitable. 6.3 Temperature
41、-measurement device A temperature-measurement device with a temperature-sensing probe consisting of a needle of diameter not more than 1 mm shall be used. The maximum allowable error shall be 0,5 C. 6.4 Timer The error of time measurement shall not be greater than 5,0 s. 7 Procedure 7.1 Preparation
42、When the small-size test piece is used for the heat-generation test, it is recommended that the insulating caps be fitted on the chuck plates. When using the larger size of test piece or when determining the fatigue resistance, the caps need not be fitted. Measure the height of the test piece to wit
43、hin 0,05 mm in the unloaded condition before placing in the flexometer. Before beginning the actual test, carry out a preliminary run of 15 min under test conditions, using a rubber of similar hardness to that of the test piece. In this way, the chuck plates (and caps when fitted) are warmed up and
44、the apparatus is brought to normal conditions. 7.2 Test operation 7.2.1 General With the device stationary, bring the two chucks into axial alignment and set up the test piece between them. Then compress the test piece axially by about 10 %; that is to about 90 % of the original height. Switch on th
45、e motor and check that the test piece is properly located. If the test piece is not running centrally, remove and re-install it. Thereafter, i.e. at the beginning of the running of the test, compress the test piece to the desired deformation or apply the desired force by means of the compression spr
46、ing or a weight. Directly thereafter, displace the right-hand (displaceable) bearing using the transverse spindle or by means of a transverse force perpendicular to the axis. The full deflection shall be reached within 10 s. The test duration begins after the required transverse deformation has been
47、 imposed. 7.2.2 Measurement of temperature rise At the end of the specified test duration, switch off the motor, remove the transverse deformation and the axial deformation, and immediately measure the temperature at the centre of the test piece with the needle probe. The time between switching off
48、the motor and the temperature measurement shall be 10 s 2 s. The temperature measurement in the test piece can be carried out with the test piece in the apparatus or after its removal. 7.2.3 Determination of resistance to fatigue breakdown Measure the period of time from the beginning of cyclic defo
49、rmation to the start of breakdown in the interior of the test piece. ISO 4666-2:2008(E) ISO 2008 All rights reserved 5If breakdown does not occur after 30 min, stop the test, unless a longer-running test is specified. In this case, report the fatigue deformability or fatigue stress instead of the limiting fatigue deformability or limiting fatigue stress (see 9.2.2). The onset of breakdown is indicated by changes in the transverse force or transverse displacement. The
