1、April 2017 English price group 13No 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!%c=“2649926www.din.deDIN IS
2、O 1431-1Rubber, vulcanized or thermoplastic Resistance to ozone cracking Part 1: Static and dynamic strain testing (ISO 14311:2012),English translation of DIN ISO 1431-1:2017-04Elastomere oder thermoplastische Elastomere Widerstand gegen Ozonrissbildung Teil 1: Statische und dynamische Dehnungsprfun
3、g (ISO 14311:2012),Englische bersetzung von DIN ISO 1431-1:2017-04Caoutchouc vulcanis ou thermoplastique Rsistance au craquelage par lozone Partie 1: Essais sous allongement statique et dynamique (ISO 14311:2012),Traduction anglaise de DIN ISO 1431-1:2017-04SupersedesDIN ISO 14311:201105www.beuth.de
4、Document comprises 21 pagesDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be considered authoritative.04.17 Contents PageNational foreword . 31 Scope 52 Normative references . 53 Terms and definitions . 54 Principle . 65 Apparatus (see Figure 1) 65.1 Test cha
5、mber 65.2 Source of ozonized air . 75.3 Means of adjusting the ozone concentration 85.4 Means of determining the ozone concentration . 85.5 Means of adjusting the gas flow . 85.6 Mounting test pieces for static strain testing 85.7 Mounting test pieces for dynamic strain testing 96 Calibration . 97 T
6、est pieces 97.1 General . 97.2 Wide test piece .107.3 Narrow test piece .108 Conditioning .108.1 Conditioning in the unstrained state108.2 Conditioning in the strained state (for static strain testing only) .119 Test conditions .119.1 Ozone concentration 119.2 Temperature 119.3 Relative humidity .11
7、9.4 Maximum elongation 1210 Static strain testing .1210.1 General .1210.2 Procedure A 1210.3 Procedure B 1210.4 Procedure C 1211 Dynamic strain testing .1311.1 General .1311.2 Continuous dynamic exposure .1311.3 Intermittent dynamic exposure 1312 Expression of results .1412.1 Procedure A 1412.2 Proc
8、edure B 1412.3 Procedure C (for static tests only) .1413 Test report . 15Annex A (informative) Ozone cracking Explanatory notes 17Annex B (normative) Calibration schedule18Annex C (informative) Ozone cracking Rating scales .20Bibliography .21A comma is used as the decimal marker.National Annex NA (i
9、nformative) Bibliography . 4DIN ISO 1431-1:2017-04 2 National foreword This standard (ISO 1431-1:2012) has been prepared by Technical Committee ISO/TC 45 “Rubber and rubber products” (Secretariat: DSM, Malaysia), Subcommittee SC 2 “Testing and analysis”. The responsible German body involved in its p
10、reparation was DIN-Normenausschuss Materialprfung (DIN Standards Committee Materials Testing), Working Committee NA 062-04-34 AA “Test procedures for physical properties of rubber”. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights.
11、DIN shall not be held responsible for identifying any or all such patent rights. DIN ISO 1431 consists of the following parts, under the general title Rubber, vulcanized or thermoplastic Resistance to ozone cracking: Part 1: Static and dynamic strain testing Part 3: Reference and alternative methods
12、 for determining the ozone concentration in laboratory test chambers The DIN Standards corresponding to the International Standards referred to in this document are as follows: ISO 1431-3 DIN ISO 1431-3 ISO 23529 DIN ISO 23529 Amendments This standard differs from DIN ISO 1431-1:2011-05 as follows:
13、a) amendments from ISO 1431-1 AMD 1:2009 have been included in the text; b) the calibration schedule has been included in Annex B; c) rating scales have been included in Annex C. Previous editions DIN 53509-1: 1964-03, 1980-03, 1990-05, 2001-01 DIN EN 53509-1 Corrigendum 1: 2003-05 DIN ISO 1431-1: 2
14、011-05 DIN ISO 1431-1:2017-04 3 National Annex NA (informative) Bibliography DIN ISO 1431-1, Rubber, vulcanized or thermoplastic Resistance to ozone cracking Part 3: Reference and alternative methods for determining the ozone concentration in laboratory test chambers DIN ISO 23529, Rubber General pr
15、ocedures for preparing and conditioning test pieces for physical test methods DIN ISO 1431-1:2017-04 4 Rubber, vulcanized or thermoplastic Resistance to ozone cracking Part 1: Static and dynamic strain testingWARNING Persons using this part of ISO 1431 should be familiar with normal laboratory pract
16、ice. This part of ISO 1431 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.1 ScopeThis part of ISO 1431
17、specifies procedures intended for use in estimating the resistance of vulcanized or thermoplastic rubbers to cracking when exposed, under static or dynamic tensile strain, to air containing a definite concentration of ozone and at a definite temperature in circumstances that exclude the effects of d
18、irect light.Great caution is necessary in attempting to relate standard test results to service performance since the relative ozone resistance of different rubbers can vary markedly depending on the conditions, especially ozone concentration and temperature. In addition, tests are carried out on th
19、in test pieces deformed in tension and the significance of attack for articles in service can be quite different owing to the effects of size and of the type and magnitude of the deformation. Explanatory notes on the nature of ozone cracking are given in Annex A.Reference and alternative methods for
20、 determining the ozone concentration are described in ISO 1431-3.2 Normative referencesThe 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 documen
21、t (including any amendments) applies.ISO 37, Rubber, vulcanized or thermoplastic Determination of tensile stress-strain propertiesISO 1431-3, Rubber, vulcanized or thermoplastic Resistance to ozone cracking Part 3: Reference and alternative methods for determining the ozone concentration in laborato
22、ry test chambersISO 18899:2004, Rubber Guide to the calibration of test equipmentISO 23529, Rubber General procedures for preparing and conditioning test pieces for physical test methods3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1threshold s
23、trainhighest tensile strain at which a rubber can be exposed at a given temperature to air containing a given concentration of ozone without ozone cracks developing on it after a given exposure periodNOTE It is important to distinguish threshold strain from limiting threshold strain defined in 3.2.D
24、IN ISO 1431-1:2017-04 5 3.2limiting threshold straintensile strain below which the time required for the development of ozone cracks increases very markedly and can become virtually infinite3.3dynamic strainstrain (normally a tensile strain) varying sinusoidally with time at some selected repetition
25、 rate or frequencyNOTE The maximum strain and the repetition rate are used to describe the dynamic strain conditions.4 PrincipleTest pieces are exposed, under static tensile strain, under continuous dynamic strain, or under alternate periods of dynamic and static strain, in a closed chamber at a con
26、stant temperature, to an atmosphere containing a fixed concentration of ozone. The test pieces are examined periodically for cracking.Three alternative evaluation procedures are described for selected values of ozone concentration and exposure temperature:a) The presence or absence of cracks is dete
27、rmined after exposure for a fixed period of time at a given static strain, dynamic strain or combination of dynamic and static strains. If required, an estimate of the degree of cracking is made.b) The time to the first appearance of cracks is determined at any given static strain, dynamic strain or
28、 combination of dynamic and static strains.c) The threshold strain is determined for any given exposure period (valid only for static tensile-strain tests).5 Apparatus (see Figure 1)WARNING Attention is drawn to the highly toxic nature of ozone. Efforts should be made to minimize the exposure of wor
29、kers at all times. In the absence of more stringent or contrary national safety regulations in the users country, it is recommended that 0,1 parts of ozone per million parts of air of the surrounding atmosphere by volume be regarded as an absolute maximum concentration whilst the maximum average con
30、centration should be appreciably lower. Unless a totally enclosed system is being used, an exhaust vent to remove ozone-laden air is advised.5.1 Test chamberThis shall be a closed, non-illuminated chamber, thermostatically controlled to within 2 C of the test temperature, lined with, or constructed
31、of, a material (for example aluminium) that does not readily decompose ozone. The dimensions shall be such that the requirements of 5.5 are met. The chamber may be provided with a window through which the surface of the test pieces can be observed. A light to examine test pieces may be installed, bu
32、t this shall remain switched off at all other times.DIN ISO 1431-1:2017-04 6 Key1 test chamber 7 air filter2 to ozone concentration measurement device 8 circulation fan3 temperature indicator 9 air outlet4 purifying column 10 heat exchanger5 flowmeter 11 ozonizer6 regulator 12 air inletFigure 1 Exam
33、ple of a test apparatus5.2 Source of ozonized airThe ozonized air shall be largely free of nitrogen oxides in order to avoid errors in the ozone concentration. One of the following items of apparatus shall therefore be used:a) ultra-violet lamp;b) silent-discharge tube.Air used for the generation of
34、 ozone or for dilution of ozonized air shall first be purified by passing it over activated charcoal and shall be free from any contaminants likely to affect the ozone concentration, the estimation of the ozone concentration or the cracking of the test pieces.NOTE Interference by oxides of nitrogen,
35、 which theoretically can be produced in a silent-discharge tube using air, is not expected at the low ozone concentrations specified.The temperature of the source shall be kept constant to within 2 C.The ozonized air shall be fed from the source into the chamber via heat exchanger to adjust its temp
36、erature to that required for the test and shall also be brought to the specified relative humidity (see 9.3).DIN ISO 1431-1:2017-04 7 5.3 Means of adjusting the ozone concentrationWhen an ultra-violet lamp is used, the ozone concentration can be controlled by adjusting either the voltage applied to
37、the tube or the input-gas or diluent-air flow rate, or by shielding part of the tube from the UV light. When a silent-discharge tube is used, the ozone concentration can be controlled by adjusting the voltage applied to the generator, the dimensions of the electrodes, or the oxygen or diluent-air fl
38、ow rate. Two-stage dilution of the ozonized air may also be used. The adjustments shall be such that they will maintain the concentration within the tolerances given in 9.1. In addition, after each occasion that the test chamber is opened for insertion or inspection of test pieces, the ozone concent
39、ration shall return to the test concentration within 30 min. The concentration of the ozone entering the chamber shall at no time exceed the concentration specified for the test.Such adjustments may be manual or automatic.5.4 Means of determining the ozone concentrationA means of sampling the ozoniz
40、ed air from the vicinity of the test pieces in the chamber and a means of estimating the ozone content shall be provided.Reference and alternative methods of determining the ozone concentration are described in ISO 1431-3.5.5 Means of adjusting the gas flowA mechanism shall be provided that is capab
41、le of adjusting the average velocity of the flow of ozonized air in the test chamber to a value of not less than 8 mm/s and preferably to a value between 12 mm/s and 16 mm/s, calculated from the measured gas flow rate in the chamber divided by the effective cross-sectional area of the chamber normal
42、 to the gas flow. In tests intended to be comparable, the velocity shall not vary by more than 10 %. The gas flow rate is the volume throughput of ozonized air in unit time, and this shall be sufficiently high to prevent the ozone concentration in the chamber being significantly reduced owing to ozo
43、ne destruction by the test pieces. The rate of destruction will vary depending on the rubber being used, the test conditions and other details of the test. As a general guide, it is recommended that the ratio of the exposed surface area of the test pieces to the gas flow rate not exceed 12 s/m (see
44、Note 1). However, the value of this ratio is not always low enough. In cases where there is doubt, the effects of destruction should be checked experimentally and, if necessary, the test piece area decreased. A diffusing screen or equivalent device shall be used to assist thorough mixing of incoming
45、 gas with that in the chamber.In order to adjust the ozone concentration in the chamber and to exclude the effect of volatile components that are produced by test pieces, air circulation apparatus that draws in fresh ambient air may be used.If high velocities are desired, a fan may be installed in t
46、he chamber to raise the velocity of the ozonized air to 600 mm/s 100 mm/s. If this is the case, it shall be stated in the test report.NOTE 1 The ratio, expressed in seconds per metre (s/m), is derived from surface area in m2and volumetric flow rate in m3/s.NOTE 2 Different results might be obtained
47、if different ozonized-air velocities are used.5.6 Mounting test pieces for static strain testingClamps shall be provided to hold the test pieces at the required elongation and with both sides in contact with the ozonized air in such a manner that the longitudinal axis of each test piece is substantially parallel to the direction of gas flow. The clamps shall be made of a material (for example aluminium) which does not readily decompose ozone.The use of a mechanically rotating carrier mounted in the test chamber and upon which the clamps or frames holding the test pieces are mo
