1、September 2016 English price group 12No 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!%Zsr“2558079www.din.deD
2、IN ISO 815-2Rubber, vulcanized or thermoplastic Determination of compression set Part 2: At low temperatures (ISO 815-2:2014),English translation of DIN ISO 815-2:2016-09Elastomere oder thermoplastische Elastomere Bestimmung des Druckverformungsrestes Teil 2: Bei niedrigen Temperaturen (ISO 815-2:20
3、14),Englische bersetzung von DIN ISO 815-2:2016-09Caoutchouc vulcanis ou thermoplastique Dtermination de la dformation rmanente aprs compression Partie 2: basses tempratures (ISO 815-2:2014),Traduction anglaise de DIN ISO 815-2:2016-09SupersedesDIN ISO 815-2:2010-09www.beuth.deDocument comprises 20
4、pagesDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be considered authoritative.08.16 A comma is used as the decimal marker. Contents Page National foreword 3 National Annex NA (informative) Bibliography 4 Introduction 51 Scope . 62 Normative references 63 Pr
5、inciple 63.1 Method 1. 63.2 Method 2. 74 Apparatus for low temperature tests 74.1 Method 1. 74.2 Method 2. 95 Calibration . 116 Test pieces 116.1 Dimensions 116.2 Preparation . 126.3 Number . 126.4 Time interval between production and testing . 126.5 Conditioning . 127 Test conditions 137.1 Duration
6、 of test 137.2 Temperature of test 138 Procedure 138.1 Method 1 138.2 Method 2 149 Expression of results .1510 Precision 1511 Test report 15Annex A (normative) Calibration schedule 17Bibliography .20DIN ISO 815-2:2016-092.National foreword This standard (ISO 815-2:2014) has been prepared by Technica
7、l Committee ISO/TC 45 “Rubber and rubber products” (Secretariat: DSM, Malaysia). 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 K
8、autschuk und Elastomeren. 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. Shore A hardness testing can be used as an alternative to IHRD t
9、esting to determine the compression set (the values given in 4.1.2 remain applicable; DIN ISO 7619-1 shall be applied in this case). The responsible committee would like to point out that the information in column 4 (“Verification frequency”) in Tables A.1 and A.2 does not correspond to that in DIN
10、ISO 815-1, Table B.1. Both parts of the ISO Standard need to be amended. DIN ISO 815 consists of the following parts, under the general title Rubber, vulcanized or thermoplastic Determination of compression set Part 1: At ambient or elevated temperatures Part 2: At low temperatures The DIN Standards
11、 corresponding to the International Standards referred to in this document are as follows: DIN 4287 DIN EN ISO 4287 DIN 23529 DIN ISO 23529 Amendments This standard differs from DIN ISO 815-2:2010-09 as follows: a) methods 1 and 2 are explicitly described; b) the calibration schedule (Annex A) has b
12、een included. DIN ISO 815-2:2016-093 Previous editions DIN 53511-3: 1940x-12 DIN 53517: 1960-07, 1987-04 DIN 53517-1: 1972-01 DIN 53517-2: 1972-01 DIN ISO 815: 2000-03 DIN ISO 815-2: 2010-09 National Annex NA (informative) Bibliography DIN EN ISO 4287, Geometrical Product Specifications (GPS) Surfac
13、e texture: Profile method Terms, definitions and surface texture parameters DIN ISO 7619-1, Rubber, vulcanized or thermoplastic Determination of indentation hardness Part 1: Durometer method (Shore hardness) DIN ISO 23529, Rubber General procedures for preparing and conditioning test pieces for phys
14、ical test methods DIN ISO 815-2:2016-094 IntroductionAllowing measurement and recording of the compression set at low temperature is very sensitive to testing conditions, and the values obtained can differ a lot especially for type B test pieces. That is why two measurement methods have been introdu
15、ced. Method 2 generally gives a higher compression set than method 1, and this difference should be taken into account when preparing material specifications.Those methods are intended to measure the ability of rubbers of hardness within the range 10 IRHD to 95 IRHD to retain their elastic propertie
16、s at specified temperatures after prolonged compression at constant strain (normally 25 %) under one of the alternative sets of conditions described. For rubber of nominal hardness 80 IRHD and above, a lower compression strain is used: 15 % for a nominal hardness from 80 IRHD to 89 IRHD, and 10 % fo
17、r a nominal hardness from 90 IRHD to 95 IRHD.Rubber, vulcanized or thermoplastic Determination of compression set Part 2: At low temperaturesDIN ISO 815-2:2016-095 WARNING 1 Persons using this part of ISO 815 should be familiar with normal laboratory practice. This part of ISO 815 does not purport t
18、o 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.WARNING 2 Certain procedures specified in this part of ISO 815 can involve
19、 the use of 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 ScopeThis part of ISO 815 specifies two methods for the determination of the compressi
20、on set characteristics of vulcanized and thermoplastic rubbers at low temperatures.Method 1 derives from the methodology used in ISO 815-1. Method 2 uses a specified testing device, allowing to measure and record the test piece thickness during recovery. Due to the load applied during recovery in me
21、thod 2, no correlation can be established between the results given by both methods.NOTE When rubber is held under compression, physical or chemical changes can occur that prevent the rubber returning to its original dimensions after release of the deforming force. The result is a set, where the mag
22、nitude of which depends on the time and temperature of compression as well as on the time, temperature, and conditions of recovery. At low temperatures, changes resulting from the effects of glass hardening or crystallization become predominant and, since these effects are reversed by raising the te
23、mperature, it is necessary for all measurements to be undertaken at the test temperature.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. Fo
24、r undated references, the latest edition of the referenced document (including any amendments) applies.ISO 18899:2013, Rubber Guide to the calibration of test equipmentISO 23529:2010, Rubber General procedures for preparing and conditioning test pieces for physical test methods3 Principle3.1 Method
25、1A test piece of known thickness is compressed at standard laboratory temperature to a defined strain, which is then maintained constant for a specified time at a fixed low temperature. The compression is totally released and, after the test piece has been allowed to freely recover at the same fixed
26、 low temperature, the thickness of the test piece is again measured.DIN ISO 815-2:2016-096 3.2 Method 2A test piece of known thickness is compressed at standard laboratory temperature to a defined strain, which is then maintained constant for a specified time at a fixed low temperature. The compress
27、ion is released and the test piece is allowed to recover at this temperature under a given pressure according to ISO 23529:2010 for thickness measurement. The thickness is measured either at intervals after the release of the strain (so that an assessment of compression set characteristics can be ob
28、tained by plotting of recovery against time at the low temperature) or a specified time after the release of the strain.4 Apparatus for low temperature tests4.1 Method 14.1.1 Compression assembly, consisting of compression plates, steel spacers, and clamping device. A typical assembly is shown in Fi
29、gure 1. A quick release mechanism as shown on Figure 2 may also be used.4.1.1.1 Compression plates, comprising a pair of parallel, flat, highly polished chromium-plated steel or highly polished stainless-steel plates, between the faces of which the test piece is compressed. The plates shall be suffi
30、ciently rigid to ensure that, with a test piece under load, no compression plate bends by more than 0,01 mm, and of sufficient size to ensure that the whole of the test piece, when compressed between the plates, remains within the area of the plates.NOTE A surface finish not worse than Ra 0,4 m (see
31、 ISO 4287) has been found to be suitable. Such an Ra can be obtained by a grinding or polishing operation.4.1.1.2 Steel spacer(s), to provide the required compression, if necessary. Whether spacer(s) will need to be used or not will depend on the design of the compression apparatus.If used, the spac
32、er(s) shall be of such size and shape that contact with the compressed test piece is avoided.The height of the spacer(s) shall be chosen so that the compression applied to the test piece is (25 2) % for hardnesses below 80 IRHD, (15 2) % for hardnesses between 80 IRHD and 89 IRHD, (10 1) % for hardn
33、esses of 90 IRHD and higher.4.1.1.3 Clamping device, a simple screw device (Figure 1) or a clamping device as shown on Figure 2 are adequate.4.1.2 Low-temperature cabinet, capable of maintaining the compression apparatus and test pieces at the test temperature within the tolerance limits specified i
34、n 7.2. The low-temperature cabinet can be mechanically refrigerated or it can be cooled directly by dry ice or liquid nitrogen.The cabinet shall be designed so that it is possible to release the test pieces and carry out the subsequent thickness measurements without direct contact, e.g. by means of
35、hand-holes fitted with gloves or a remote-handling device. The cabinet shall be capable of maintaining the temperature within specified limits while these operations are being carried out.The time to reach a steady-state temperature depends on the type of cabinet and the overall heat capacity of the
36、 compression apparatus. To obtain test results which can be compared with each other, it is necessary, in the case of a 24 h test duration, to reach the steady-state temperature within the specified limits in the interior of the test pieces in not more than 3 h.DIN ISO 815-2:2016-097 4.1.3 Pair of t
37、ongs, for handling the test pieces.4.1.4 Thickness gauge, with an accuracy of 0,01 mm (see ISO 23529:2010, 7.1), having a flat solid base-plate and exerting a pressure of 22 kPa 5 kPa for solid rubber of hardness equal to or greater than 35 IRHD, or a pressure of 10 kPa 2 kPa if the hardness is less
38、 than 35 IRHD. For comparative tests, the same dimensions of the circular foot shall be used.NOTE When using a digital gauge, a resolution of 0,001 mm is needed to obtain the required accuracy.4.1.5 Timing device, for measuring the recovery time, with a precision of 1 sKey1 test piece 5 lower plate2
39、 spacer 6 part formed for clamping in a vice3 nut 7 locating pin4 upper plate 8 screwFigure 1 Example of assembly for the determination of compression setDIN ISO 815-2:2016-098 Figure 2 Example of a quick-release mechanism4.2 Method 24.2.1 Compression apparatus, consisting of compression plates, spa
40、cer(s) (optional), a thickness gauge, a temperature sensor, and a device for applying a specified pressure for thickness measurements. The measurement pressure for thickness measurements is the same as that specified in ISO 23529:2010.The compression apparatus shall be capable of applying the compre
41、ssion and maintaining it during the whole duration of the test, and it shall be possible to keep the apparatus in a low-temperature cabinet at the specified test temperature. Care shall be taken to ensure that there is as little influence on the test as possible by conduction of heat away from the t
42、est piece, for example, through metal parts which are connected with the outside of the low-temperature cabinet.The part of the apparatus with the compression plates and the test piece shall be within the low-temperature cabinet during the whole of the test, but the thickness gauge may be located ou
43、tside the cabinet.An example of a compression apparatus is shown in Figure 3.It shall be possible to release the compression of the test piece without opening the low-temperature cabinet.4.2.1.1 Compression plates, comprising a pair of parallel, flat, highly polished chromium-plated steel or highly
44、polished stainless-steel plates, between the faces of which the test piece is compressed.The plates shall be sufficiently rigid to ensure that, with a test piece under load, no compression plate bends by more than 0,01 mm, and of sufficient size to ensure that the whole of the test piece, when compr
45、essed between the plates, remains within the area of the plates.NOTE A surface finish not worse than Ra 0,4 m (see ISO 4287) has been found to be suitable. Such an Ra can be obtained by a grinding or polishing operation.DIN ISO 815-2:2016-099 4.2.1.2 Steel spacer(s), to provide the required compress
46、ion, if necessary. Whether spacer(s) will need to be used or not will depend on the design of the compression apparatus.If used, the spacer(s) shall be of such size and shape that contact with the compressed test piece is avoided.The height of the spacer(s) shall be chosen so that the compression ap
47、plied to the test piece is (25 2) % for hardnesses below 80 IRHD, (15 2) % for hardnesses between 80 IRHD and 89 IRHD, (10 1) % for hardnesses of 90 IRHD and higher.4.2.2 Temperature measurement device, inserted in one of the plates, measuring the temperature directly with an accuracy of 0,5 C.Key1 screw 7 compression plates2 thickness measurement gauge 8 spacer (optional)3 rubber lid 9 test piece4 insulating lid 10 temperature sensorDIN ISO 815-2:2016-09105 aluminium lid 11 w
