1、December 2015English price group 11No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 83.060!%I|“2385689www.din.deDIN
2、ISO 3384-1Rubber, vulcanized or thermoplastic Determination of stress relaxation in compression Part 1: Testing at constant temperature (ISO 3384-1:2011 + Amd.1:2013),English translation of DIN ISO 3384-1:2015-12Elastomere oder thermoplastische Elastomere Bestimmung der Spannungsrelaxation unter Dru
3、ck Teil 1: Prfung bei konstanter Temperatur (ISO 3384-1:2011 + Amd.1:2013),Englische bersetzung von DIN ISO 3384-1:2015-12Caoutchouc vulcanis ou thermoplastique Dtermination de la relaxation de contrainte en compression Partie 1: Essais temprature constante (ISO 3384-1:2011 + Amd.1:2013),Traduction
4、anglaise de DIN ISO 3384-1:2015-12SupersedesDIN ISO 3384:2008-07www.beuth.deDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be considered authoritative.Document comprises 19 pages11.15 DIN ISO 3384-1:2015-122A comma is used as the decimal marker. Contents Page
5、 National foreword . 3 National Annex NA (informative) Bibliography . 4 Introduction 5 1 Scope . 6 2 Normative references . 6 3 Terms and definitions 7 4 Principle 7 5 Apparatus 7 6 Test piece 8 6.1 Test piece type and test piece preparation . 8 6.2 Measurement of dimensions of test pieces . 9 6.3 N
6、umber of test pieces . 9 6.4 Time interval between forming and testing 9 6.5 Conditioning of test pieces . 9 7 Duration, temperature and test liquid 10 7.1 Duration of test 10 7.2 Temperature of exposure 10 7.3 Immersion liquids . 10 8 Procedure . 10 8.1 Preparation 10 8.2 Thickness measurement 10 8
7、.3 Method A . 11 8.4 Method B . 11 9 Expression of results 12 10 Precision . 12 11 Test report . 12 Annex A (informative) Precision 14 Annex B (informative) Guidance for using precision results . 16 !Annex C (normative) Calibration schedule 17“ Bibliography . 19 National foreword International Stand
8、ard ISO 3384-1:2011 Rubber, vulcanized or thermoplastic Determination of stress relaxation in compression Part 1: Testing at constant temperature and International Amendment ISO 3384-1:2011 Amendment 1:2013 have been adopted in this standard without any modification. This standard includes Amendment
9、 1 published by ISO on 15 March 2013. The start and finish of text introduced or altered by amendment is indicated in the text by tags !“. This document (ISO 3384-1:2011 + Amd. 1:2013) has been prepared by Technical Committee ISO/TC 45 “Rubber and rubber products” (Secretariat: DSM, Malaysia), Subco
10、mmitte SC 2 “Testing and analysis” (Secretariat: SIS, Sweden). The responsible German body involved in its preparation was DIN-Normenausschuss Materialprfung (DIN Standards Committee Materials Testing), Working Committee NA 062-04-34 AA Prfung der physikalischen Eigenschaften von Kautschuk und Elast
11、omeren. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. DIN and/or DKE shall not be held responsible for identifying any or all such patent rights. The DIN Standards corresponding to the International Standards referred to in this
12、 document are as follows: ISO 37 DIN 53504 ISO 188 DIN 53508 ISO 1817 DIN ISO 1817 ISO 3601-1 DIN ISO 3601-1 ISO 23529 DIN ISO 23529 Amendments This standard differs from DIN ISO 3384:2008-07 as follows: a) changing temperatures have been dropped and will be dealt with in another part of the standar
13、ds series; b) normative references have been updated; c) Annex C (normative) “Calibration schedule” has been added; d) the standard has been editorially revised. Previous editions DIN 53537: 1977-02, 1985-09 DIN ISO 3384: 2004-05, 2008-07 DIN ISO 3384-1:2015-123National Annex NA (informative) Biblio
14、graphy DIN 53504, Testing of rubber Determination of tensile strength at break, tensile stress at yield, elongation at break and stress values in a tensile test DIN 53508, Testing of rubber Accelerated ageing DIN ISO 1817, Rubber, vulcanized Determination of the effect of liquids DIN ISO 3601-1, Flu
15、id power systems O-rings Part 1: Inside diameters, cross-sections, tolerances and designation codes DIN ISO 23529, Rubber General procedures for preparing and conditioning test pieces for physical test methods DIN ISO 3384-1:2015-124Rubber, vulcanized or thermoplastic Determination of stress relaxat
16、ion in compression Part 1: Testing at constant temperature Introduction When a constant strain is applied to rubber, the force necessary to maintain that strain is not constant but decreases with time; this behaviour is called “stress relaxation”. Conversely, when rubber is subjected to a constant s
17、tress, an increase in the deformation takes place with time; this behaviour is called “creep”. The processes responsible for stress relaxation can be physical or chemical in nature, and under all normal conditions both types of process will occur simultaneously. However, at normal or low temperature
18、s and/or short times, stress relaxation is dominated by physical processes whilst at high temperatures and/or long times chemical processes are dominant. If the lifetime of a material is to be investigated, it can be determined using the air oven ageing test described in ISO 11346 (see the Bibliogra
19、phy). In addition to the need to specify the temperatures and time intervals in a stress relaxation test, it is necessary to specify the initial stress and the previous mechanical history of the test piece since these might also influence the measured stress relaxation, particularly in rubbers conta
20、ining fillers. The most important factor in achieving good repeatability and reproducibility when making stress relaxation tests is to keep the temperature and compression constant during all measurements. DIN ISO 3384-1:2015-125WARNING Persons using this part of ISO 3384 should be familiar with nor
21、mal laboratory practice. This part of ISO 3384 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 conditions. IMPORTAN
22、T Certain procedures specified in this part of ISO 3384 might 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 This part
23、of ISO 3384 specifies two methods for determining the decrease in counterforce exerted by a test piece of vulcanized or thermoplastic rubber which has been compressed to a constant deformation and maintained thus at a predetermined test temperature. The counterforce can be determined either by means
24、 of a continuous-measurement system or by a discontinuous-measurement one. Two forms of test piece are permitted: cylindrical test pieces and rings. Different shapes and sizes of test piece give different results, and comparison of results should be limited to test pieces of similar size and shape.
25、The use of ring test pieces is particularly suitable for the determination of stress relaxation in liquid environments. This part of ISO 3384 deals only with testing at constant ambiant or elevated temperature. Testing at temperatures below standard laboratory temperature is not specified. The metho
26、ds have been used for low-temperature testing, but their reliability under these conditions is not proven. 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, t
27、he latest edition of the referenced document (including any amendments) applies. ISO 37:2011, Rubber, vulcanized or thermoplastic Determination of tensile stress-strain properties ISO 188:2011, Rubber, vulcanized or thermoplastic Accelerated ageing and heat resistance tests ISO 1817, Rubber, vulcani
28、zed or thermoplastic Determination of the effect of liquids ISO 3601-1:2008, Fluid power systems O-rings Part 1: Inside diameters, cross-sections, tolerances and designation codes DIN ISO 3384-1:2015-126ISO 18899:2004, Rubber Guide to the calibration of test equipment ISO 23529:2010, Rubber General
29、procedures for preparing and conditioning test pieces for physical test methods 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 compression stress relaxation reduction in compressive force, expressed as a percentage of the initial force, whic
30、h occurs with time after the application of a constant compressive strain 4 Principle A test piece of vulcanized or thermoplastic rubber is compressed to a constant deformation and maintained at a predetermined test temperature. The decrease in counterforce is then measured. In method A, the compres
31、sion is applied and all counterforce measurements are made at the test temperature. In method B, the compression is applied and all counterforce measurements are made at a standard laboratory temperature. The test pieces are stored at the test temperature. The test can be conducted in a gaseous or a
32、 liquid environment. The two methods, A and B, of carrying out the measurement do not give the same values of stress relaxation, and comparison of values obtained from the two methods should be avoided. The method selected for use depends on the purpose of the test. Thus, for fundamental studies and
33、 in applications where sealing at elevated temperatures is a problem, method A might be preferred, and in applications where temperature cycling from normal to an elevated temperature is a problem, method B might be preferred. NOTE Other methods can be used for specific purposes, such as applying th
34、e compression at standard laboratory temperature and making all counterforce measurements at a different temperature. 5 Apparatus 5.1 Compression device, consisting of two parallel, flat, highly polished plates made from chromium-plated or stainless steel or another corrosion-resistant material, bet
35、ween the faces of which the test pieces are compressed. Flatness, surface roughness, parallelism and rigidity of the plates are all important. The surfaces of the compression plates shall be ground and polished. Compression plates shall be flat and parallel and shall not undergo any distortion when
36、the test load is applied. NOTE A finish to the surface giving a roughness profile Ra (see ISO 4287) of not worse than 0,4 m has been found to be suitable. Such a roughness profile Ra can be obtained by grinding or polishing. When the apparatus is assembled without a test piece, the gap between the p
37、lates shall not vary by more than 0,01 mm. When the test assembly is subjected to the test load with a test piece between the plates, neither compression plate shall bend by more than 0,01 mm. The plates shall be of sufficient size to ensure that the whole of the compressed test piece is within the
38、area of the plates and can expand freely laterally. DIN ISO 3384-1:2015-127For ring test pieces, the plates shall have holes of at least 2 mm diameter drilled through their centre portions to allow equalization of pressure and circulation of fluid inside the ring-shaped test piece. It shall be possi
39、ble to connect the compression device to suitable equipment for compressing the test piece to the specified compression at the specified speed and for measuring the counterforce exerted by the compressed test piece with an accuracy of 1 % of the measured value. The device shall be capable of setting
40、 the compression and maintaining it during the whole duration of the test, and it shall be possible to keep the device in an oven at the specified test temperature. Care shall be taken to ensure that there is no loss of heat from the test piece, for example by conduction through metal parts which ar
41、e connected with the outside of the oven. 5.2 Counterforce-measuring device, capable of measuring compression forces in the desired range with an accuracy of 1 % of the measured value. The device may be a continuous-measurement system which monitors the test piece during the whole duration of the te
42、st, making it possible to measure the change in the counterforce with time on a continuous basis. The deformation of the test piece shall be kept within 0,01 mm for the duration of the test. Alternatively, a compression-testing machine may be used to measure the counterforce at prescribed time inter
43、vals. In this case, the force necessary to cause a slight increase in the compression of the test piece is measured. This additional compression shall be as small as possible and in no case greater than a force of 1 N for balance-type machines, or greater than 0,05 mm for stress/strain-type machines
44、, applied in either case without overshoot. The whole of the force exerted by the test piece as a result of the extra compression shall act on the force-measuring device. It shall also be possible to repeat the compression to within 0,01 mm from one measurement to another. 5.3 Test environment 5.3.1
45、 For tests in gaseous media, an air oven complying with the requirements of ISO 188 shall be used. An oven meeting the requirements specified for one of the ovens used in ISO 188:2011, method A, is recommended. NOTE If the testing is done in nitrogen, oxidative ageing will be eliminated and the resu
46、lt will be due to thermal ageing only. This may be used to simulate conditions where the product is not exposed to air, such as seals used in oil or steam. 5.3.2 For tests in liquids, the compression device shall be totally immersed in a liquid in a bath, or a closed vessel for volatile or toxic flu
47、ids, such that free circulation of the liquid can take place through the holes in the compression plates. The liquid shall be maintained at the specified temperature by proper control of a heater and circulation of the liquid in the bath or, alternatively, by placing the liquid bath and compression
48、device within an air oven as specified above. 5.4 Temperature-measuring equipment, with a sensing element of suitable precision. The temperature-sensing element shall be fitted in such a way that it accurately measures the temperature of the test piece. 6 Test piece 6.1 Test piece type and test piec
49、e preparation 6.1.1 General Test pieces shall be prepared either by moulding or in accordance with ISO 23529, by cutting from moulded sheets or products. NOTE The results obtained from test pieces of different sizes are not comparable. DIN ISO 3384-1:2015-1286.1.2 Cylindrical test pieces The test piece shall be a cylindrical disc of diameter 13 mm 0,5 mm and thickness 6,3 mm 0,3 mm. 6.1.3 Ring test pieces The preferred ring test piece is a ring of
