1、August 2016 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!%YE*“2543407www.din.deDIN
2、ISO 7743Rubber, vulcanized or thermoplastic Determination of compression stress-strain properties (ISO 7743:2011),English translation of DIN ISO 7743:2016-08Elastomere oder thermoplastische Elastomere Bestimmung des Druckverformungs-Verhaltens (ISO 7743:2011),Englische bersetzung von DIN ISO 7743:20
3、16-08Caoutchouc vulcanis ou thermoplastique Dtermination des proprits de constrainte/dformation en compression (ISO 7743:2011),Traduction anglaise de DIN ISO 7743:2016-08SupersedesDIN ISO 7743:2006-11www.beuth.deDocument comprises 26 pagesDTranslation by DIN-Sprachendienst.In case of doubt, the Germ
4、an-language original shall be considered authoritative.07.16 A comma is used as the decimal marker. Contents PageNational foreword . 3 Introduction . 5 1 Scope 6 2 Normative references 7 3 Terms and definitions . 7 4 Principle . 7 5 Apparatus and materials. 7 6 Calibration 8 7 Test pieces . 8 8 Numb
5、er of test pieces . 9 9 Time-lapse between vulcanization and testing 9 10 Conditioning 9 11 Temperature of test . 10 12 Procedure . 10 12.1 Measurement of test pieces . 10 12.2 Determination of stress-strain properties. 10 13 Expression of results 11 13.1 For methods A, B and C 11 13.2 For method D
6、. 12 14 Test report 13 15 Precision for methods A and D 13 Annex A (informative) Influence of test piece geometry . 14 Annex B (informative) Extrapolation of results to non-standard test pieces . 18 Annex C (normative) Calibration schedule 21 Annex D (informative) Precision for methods A and D 23 Bi
7、bliography 26 National Annex NA (informative) Bibliography . 4 DIN ISO 7743:2016-082 National foreword This standard (ISO 7743:2011) has been prepared by Technical Committee ISO/TC 45 “Rubber and rubber products” (Secretariat: DSM, Malaysia) The responsible German body involved in its preparation wa
8、s DIN-Normenausschuss Materialprfung (DIN Standards Committee Materials Testing), Working Committee NA 062-04-34 AA Prfung der physikalischen Eigenschaften von Kautschuk und Elastomeren. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rig
9、hts. 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 Clause 2 of this standard are as follows: ISO 815-1 DIN ISO 815-1 ISO 4287 DIN EN ISO 4287 ISO 23529 DIN ISO 23529 Amendments
10、 This standard differs from DIN ISO 7743:2006-11 as follows: a) a calibration method has been added; b) precision results have been added. Previous editions DIN ISO 7743: 1993-08, 2006-11 DIN ISO 7743:2016-083 National Annex NA (informative) Bibliography DIN ISO 815-1, Rubber, vulcanized or thermopl
11、astic Determination of compression set Part 1: At ambient or elevated temperatures DIN EN ISO 4287, Geometrical product specifications (GPS) Surface texture: Profile method Terms, definitions and surface texture parameters DIN ISO 23529, Rubber General procedures for preparing and conditioning test
12、pieces for physical test methods DIN ISO 7743:2016-084 Introduction Knowledge of compression stress-strain properties is important in the design of, for instance, bridge bearings, anti-vibration mountings and O-rings. Measurement of compression stress-strain behaviour is also used for the quality co
13、ntrol of small O-rings and other small products (i.e. those under 2 mm thick) where hardness cannot easily be measured. Compression tests are also used to detect the presence of porosity in products such as pipe sealing rings. Compression can be uniaxial or biaxial depending on test piece shape and
14、experimental conditions. If there is no friction at the interface between the test piece and the compression device, compression is uniaxial. If friction is significant, the test piece shape affects the nature of the compression. When the thickness of the test piece is small, Saint Venants principle
15、 is not applicable: the boundary condition at the interface influences the stress and strain fields and compression becomes biaxial (the thinner the test piece, the higher the biaxiality). The test piece behaves as if an additional radial compression were applied (friction hampers the radial expansi
16、on due to axial compression) and this phenomenon has to be taken into account when material properties such as moduli are to be derived from compression results. DIN ISO 7743:2016-085 Rubber, vulcanized or thermoplastic Determination of compression stress-strain properties WARNING Persons using this
17、 International Standard should be familiar with normal laboratory practice. This International Standard 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 com
18、pliance with any national regulatory conditions. 1 Scope This International Standard specifies methods for the determination of the compression stress-strain properties of vulcanized or thermoplastic rubber using a standard test piece, a product or a part of a product. Four procedures are given: usi
19、ng standard test piece A with the metal plates lubricated (method A); using standard test piece A with the metal plates bonded to the test piece (method B); using standard test piece B (method C); using a product or a part of a product with the metal plates lubricated (method D). The four procedures
20、 do not give the same results. Method A (test piece A, lubricated) gives results which are dependent only on the modulus of the rubber and are independent of the test piece shape, provided that complete slip conditions are achieved. Effective lubrication is sometimes difficult to achieve, however, a
21、nd it is prudent to inspect the variance in the test results from replicate test pieces for indications of erratic slip conditions. Method B (test piece A, bonded) gives results which are dependent on both the modulus of the rubber and the test piece shape. The dependence on test piece shape is stro
22、ng and, consequently, the results are markedly different from those obtained with lubricated test pieces. Method C (test piece B) gives results which are independent of both the test piece shape and the lubrication conditions. This test piece is more appropriate and more convenient when intrinsic ma
23、terial properties are to be determined (see Annex A for details). For products (method D), the result is dependent on the shape, but as tests on products are mainly comparative, this is acceptable. NOTE For well-specified product shapes, such as O-rings, the result can be correlated to the hardness
24、value. Provision is made for the use of test pieces of different size and/or shape from the specified test pieces, but extrapolation of the results obtained to other sizes and shapes can prove impossible. Information on the effect of size and shape of test piece and of bonding or lubrication is give
25、n in Annex A. The method is not suitable for materials that exhibit high set. DIN ISO 7743:2016-086 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 late
26、st edition of the referenced document (including any amendments) applies. ISO 18899:2004, Rubber Guide to the calibration of test equipment ISO 23529, Rubber General procedures for preparing and conditioning test pieces for physical test methods 3 Terms and definitions For the purposes of this docum
27、ent, the following terms and definitions apply. 3.1 compression stress stress applied so as to cause a deformation of the test piece in the direction of the applied stress, expressed as the force divided by the original area of cross-section perpendicular to the direction of application of the force
28、 3.2 compression strain deformation of the test piece in the direction of the applied stress divided by the original dimension in that direction NOTE The compression strain is commonly expressed as a percentage of the original dimension of the test piece. 3.3 compression modulus secant modulus appli
29、ed stress calculated on the original area of cross-section divided by the resultant strain in the direction of application of the stress 3.4 stiffness at 25 % compression force which needs to be applied to a product or a part of a product to compress it by 25 %, expressed in newtons per metre or in
30、newtons, depending on the shape of the test piece 4 Principle A test piece (lubricated or bonded) is compressed at a constant speed between the compression plates until a pre-determined strain is reached. 5 Apparatus and materials 5.1 Flat metal plates, of uniform thickness and having lateral dimens
31、ions greater than or equal to those of test pieces for bonding or at least 20 mm greater than those of test pieces for lubrication. For methods A and D, one surface of each plate shall be highly polished. NOTE A surface finish not worse than Ra 0,4 m (see ISO 42872) has been found to be suitable. Su
32、ch an Ra can be obtained by a grinding or polishing operation. For method B, one surface of each plate shall be suitably prepared for the bonding system to be used. For method C, no specific preparation of the contact surfaces is required. DIN ISO 7743:2016-087 5.2 Dies and cutters (if required), fo
33、r preparing test pieces, complying with the relevant requirements of ISO 23529. 5.3 Thickness gauge, complying with the relevant requirements of ISO 23529. 5.4 Compression-testing machine, complying with the requirements of ISO 58934, equipped with means of autographic recording of the force-deforma
34、tion relationship to an accuracy corresponding to grade 1 in respect of force. When testing standard test pieces in methods A, B and C and larger test pieces in method D, it shall be possible to determine the displacement with an accuracy of 0,02 mm, including corrections for load cell and device st
35、iffness. When testing products with a height less than that of the standard test piece, it shall be possible to determine the displacement with an accuracy of 0,2 % of the height of the test piece, including corrections for load cell and device stiffness. The machine shall be fitted with parallel co
36、mpression platens at least as large as the metal plates (5.1), and shall be capable of operating at a speed of (10 2) mm/min. NOTE 1 For methods A and D, the compression platens can be used directly without the metal plates, provided they have the required surface finish. NOTE 2 For method C, the co
37、mpression platens can be used directly, whatever the surface finish. Machines with y-time recorders can give erroneous results because of: inertia effects; deformation caused by compliance in the load cell or machine frame. Machines with x-y recorders are therefore preferred. When testing lubricated
38、 test pieces, a suitable guard should be provided to avoid damage or injury should the rubber be ejected when strained. 5.5 Lubricant, having no significant effect on the rubber under test, for methods A, C and D. NOTE For most purposes, a silicone or fluorosilicone fluid having a kinematic viscosit
39、y of 0,01 m2/s is suitable. For method C, lubrication is recommended though it is not necessary (see Annex A). 6 Calibration The test apparatus shall be calibrated in accordance with Annex C. 7 Test pieces Standard test piece A: the standard test piece for both method A and method B is a cylinder of
40、 diameter (29 0,5) mm and height (12,5 0,5) mm. Standard test piece B: the standard test piece for method C is a cylinder of diameter (17,8 0,15) mm and height (25 0,25) mm. Test pieces can be cut or moulded. Cut test pieces shall be prepared in accordance with ISO 23529. DIN ISO 7743:2016-088 Other
41、 test pieces can be used, but extrapolation of the results might not be possible (see Annex B). For method B, test pieces can be directly moulded to the metal plates using a suitable mould and bonding system or adhered to the plates using suitable non-solvent adhesive systems. It is essential to hav
42、e test pieces with flat and parallel surfaces. For method D, the test piece is a product, or a part of a product, or multiples thereof. For profiles, a length of 50 mm to 100 mm shall be used as the test piece (or two such lengths together if it is necessary to increase the force reading). For ring-
43、shaped products with an inner diameter of 50 mm to 100 mm, the whole product shall be used. For small products, two or more products can be tested side by side, parallel to each other, to increase the force reading. 8 Number of test pieces At least three test pieces, or sets of test pieces, shall be
44、 tested. 9 Time-lapse between vulcanization and testing Unless otherwise specified for technical reasons, the following requirements shall be observed (see ISO 23529). For all test purposes, the minimum time between vulcanization and testing shall be 16 h. For non-product tests, the maximum time bet
45、ween vulcanization and testing shall be four weeks and, for evaluations intended to be comparable, the tests, as far as possible, shall be carried out after the same time interval. For product tests, whenever possible, the time between vulcanization and testing shall not exceed three months. In othe
46、r cases, tests shall be made within two months of the date of receipt of the product by the customer. 10 Conditioning Samples and test pieces shall be protected from light as completely as possible during the interval between vulcanization and testing. Samples, after any necessary preparation, shall
47、 be conditioned at standard laboratory temperature (see ISO 23529) for at least 3 h before the test pieces are cut. The test pieces can be marked, if necessary, and measured and tested immediately. If not tested immediately, they shall be kept at the standard laboratory temperature until tested. If the preparation involves buffing, the interval between buffing and testing shall not exceed 72 h. Moulded test pieces shall be conditioned at standard laboratory temperature for at least 3 h immedia
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