《BS-4443-2-1988.pdf》由会员分享,可在线阅读,更多相关《BS-4443-2-1988.pdf(8页珍藏版)》请在三一文库上搜索。
1、BRITISH STANDARD BS 4443-2: 1988 Methods of test for Flexible cellular materials Part 2: Method 7. Indentation hardness tests UDC 678-405.8:678.074:620.178.15 Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 08:48:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4443-2:1988 This British Standa
2、rd, having been prepared under the direction of the Plastics Standards Committee and the Rubber Standards Committee, was published under the authority of the Board of BSI and comes into effect on 29 February 1988 BSI 03-1999 First published March 1972 First revision 29 February 1988 The following BS
3、I references relate to the work on this standard: Committee reference PLM/RUM/10 Draft for comment 86/35475 DC ISBN 0 580 15995 7 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Plastics Standards Committee (PLM/-) and the Rubber Standar
4、ds Committee (RUM/-) to Technical Committee PLM/RUM/10, upon which the following bodies were represented: British Plastics Federation British Railways Board British Rigid Urethane Foam Manufacturers Association British Rubber Manufacturers Association Department of the Environment (Building Research
5、 Establishment) Furniture Industry Research Association Furniture, Timber and Allied Trades Union Ministry of Defence National Bedding Federation Phenolic Foam Manufacturers Association RAPRA Technology Ltd Society of British Aerospace Companies Limited Society of Motor Manufacturers and Traders Lim
6、ited Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 08:48:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4443-2:1988 BSI 03-1999i Contents Page Committees responsibleInside front cover Forewordii 0Introduction1 1Scope1 2Defi
7、nitions1 3Apparatus1 4Conditioning1 5Test specimen2 6Test procedures2 7Repeat tests2 8Test report2 Publications referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 08:48:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4443-2:1988 ii BSI 03-1999 Foreword This Part of
8、BS 4443 has been prepared under the direction of the Plastics Standards Committee and the Rubber Standards Committee as a revision of BS 4443-2:1972 which is withdrawn. This method comprises procedures described in ISO 2439 “Polymeric materials, cellular flexible Determination of hardness (indentati
9、on technique)”. In the UK, however, expert opinion deprecates the use of procedure C: “Determination of indentation hardness check”, of ISO 2439, except for factory control testing; consequently, the details of this procedure have been included only as a note to 6.2. Particular attention is drawn in
10、 this revision to changes in the minimum time permitted after manufacture before testing and to changes in the conditioning procedures. In view of the importance of hardness measurements on flexible cellular materials, method 7 is published separately as BS 4443-2. Attention is also drawn to BS 4443
11、-1, which lists six other methods of test for flexible cellular materials and covers measurement of dimensions, apparent density, tensile strength and elongation at break, cell count, compression stress-strain and compression set. The following Parts of BS 4443 cover other methods of test for the ma
12、terials. Part 3:Method 8, Determination of creep Method 9, Determination of dynamic cushioning performance; Part 4:Method 10, Determination of solvent swelling Method 11, Humidity ageing at an elevated temperature Method 12, Heat ageing; Part 5:Method 13, Test for dynamic fatigue by constant load po
13、unding; Part 6:Method 14, Preparation of water extract Method 15, Determination of tear strength Method 16, Determination of air flow value; Part 7:Method 17, Determination of tear strength of flexible cellular material with an integral skin. A British Standard does not purport to include all the ne
14、cessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pag
15、es 1 and 2, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 08:48:56 GMT+00:00 2006, Un
16、controlled Copy, (c) BSI BS 4443-2:1988 BSI 03-19991 0 Introduction The indentation hardness is a measure of load-bearing properties. The procedures described in this Part of BS 4443 can be used for testing finished articles and the characterization of bulk material. The test procedures are applicab
17、le to latex, PVC and polyurethane flexible cellular plastics of the open cell type. The results obtained in these tests pertain to these test conditions only and cannot, in general, be used directly for design purposes. 1 Scope This Part of BS 4443 describes two test procedures for determining the i
18、ndentation hardness of flexible cellular products of polymeric origin. Procedure A (indentation hardness index) gives a single indentation measurement for laboratory test purposes. Procedure B (indentation hardness characteristics) provides information about the shape of the indentation hardness cur
19、ve. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions For the purposes of this Part of BS 4443 the following definitions apply. 2.1 indentation hardness the total force, in newtons, required to produce, under specified conditions, a sp
20、ecified indentation of the test specimen 2.2 material indentation hardness index the result of a test conducted in accordance with 6.2 (procedure A) on the standard size test specimen without plying up 2.3 product indentation hardness index the result of a test conducted in accordance with 6.2 (proc
21、edure A) on an article of non-standard size or shape or on plied up material 2.4 material indentation hardness characteristics the results of a test conducted in accordance with 6.3 (procedure B) on the standard size test specimen without plying up 2.5 product indentation hardness characteristics th
22、e results of a test conducted in accordance with 6.3 (procedure B) on an article of non-standard size or shape or on plied up material 3 Apparatus 3.1 Testing machine, capable of indenting the test specimen between a supporting surface and an indentor, which shall have a uniform relative motion, in
23、the vertical direction, of 100 20 mm/min. The testing machine shall have a means of measuring the force required to produce the specified indentation (see 6.2 and 6.3) with a precision of 1%, or 1 N, whichever is the greater, and it shall have a means of measuring the sample thickness under load wit
24、h an accuracy of 0.25 mm. The testing machine shall also be capable of maintaining the specified degree of indentation, with an accuracy of 0.25 mm for the specified period. Unless otherwise specified, the test specimen shall be supported on a smooth, flat, horizontal and rigid surface, larger than
25、the test specimen, and suitably vented with holes 6 mm in diameter, and approximately 20 mm pitch, to allow the escape of air from below the test specimen. NOTEMoulded products are frequently made with a base which is not flat. Such products may be tested, if so specified, on a matrix which is shape
26、d to conform closely to the base of the moulded product. Product indentation hardness indices obtained in this way may be more reproducible than when measured on the flat surface of the testing machine, but will not in general give the same hardness index. 3.2 Indentor, of flat, circular shape, moun
27、ted by a ball joint free from vertical movement, and having a diameter of 200mm with a corner radius of 1.0mm at the lower edge. The lower surface shall be smooth, but not polished. 4 Conditioning Material shall not be tested less than 72 h after manufacture, unless, at either 16 h or 48 h after man
28、ufacture, it can be demonstrated that the mean indentation hardness values obtained do not differ by more than 10% from those obtained after 72 h. Testing is permitted at either 16 h or 48 h if, at the selected time, the above criteria have been satisfied. Prior to the test, the test pieces shall be
29、 stored for at least 16 h under the following standard conditions: 23 2 C, 50 5 % relative humidity. NOTEThis period can form the latter part of the period following manufacture. 3+ 0 0.5+ 0 Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 08:48:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS
30、 4443-2:1988 2 BSI 03-1999 5 Test specimen Material shall be cut to provide a standard size test specimen 380mm square and with a thickness of 50 2 mm. Sheets below this thickness shall be plied up as near to this thickness as possible. NOTE 1Products or articles of non-standard shape should be test
31、ed with indentor positions as agreed between the purchaser and the supplier. NOTE 2Results on plied up material and on finished articles may not be the same as would be obtained with the specified size of test specimen. 6 Test procedures 6.1 Both procedures A and B Test immediately after conditionin
32、g. Position the test specimen on the support plate (3.1) so that the centre of the test specimen or other agreed test area is located below the centre of the indentor (3.2). Specimens having cavities on one side are placed with the cavity side next to the support plate. Apply a force of 5N to the se
33、lected test area and measure the thickness. Indent the test specimen at a rate of 100 20 mm/min to produce an indentation of 70 2.5 % of the thickness. After reaching 70 % indentation, release the force at the same rate. Repeat this loading and unloading twice more. 6.2 Procedure A. Determination of
34、 indentation hardness index Immediately after the third unloading, indent the test specimen to produce an indentation of 40 1 % of the thickness. Maintain this indentation for a period of 30 1 s, then note the corresponding force, in newtons, and release the force. NOTE 1This procedure corresponds t
35、o procedure A of ISO 2439. NOTE 2For quality control purposes in the factory, procedure A may be shortened by omitting the “dwell period” of 30 1 s. The variability of results gained in this way will be higher. It should also be noted that the results obtained in this way may be related to results o
36、btained with procedure A, but will not usually be the same. In addition, the testing machine should have its force gauge fitted with a tell-tale needle, or should be equipped to make autographic load indentation plots. This shortened procedure corresponds to procedure C, “Determination of indentatio
37、n hardness check” of ISO 2439 (see foreword). 6.3 Procedure B. Determination of indentation hardness characteristics NOTEThis procedure corresponds to procedure B of ISO 2439. Immediately after the third unloading (see 6.1), carry out the following. a) Indent the test specimen to produce an indentat
38、ion of 25 1 % of the thickness. b) Maintain this indentation for a period of 30 1 s. c) Measure the force. d) Increase the indentation to an indentation of 40 1 %. e) Maintain this indentation for a period of 30 1 s. f) Measure the force. g) Increase this indentation to an indentation of 65 1 %. h)
39、Maintain this indentation for a period of 30 1 s. j) Measure the force. k) Release the force. 7 Repeat tests For repeat tests on the same area of the same test specimen, a minimum recovery time of 24 h shall be allowed. 8 Test report The test report shall include the following: a) the procedure used
40、 (see clause 6) and the type of result obtained (e.g. product indentation hardness characteristics), or whether the shortened procedure was used (see note 2 to 6.2); b) the indentation hardness value(s); values up to 100 N should be quoted to the nearest unit, values of over 100 N should be quoted t
41、o the nearest 5 N; c) in the case of products or finished articles, the agreed positions of the indentor that have been used; d) the dimensions of the test specimen, and especially the thickness as determined in 6.1; e) the number of plies, where applicable; f) whether skins were present and, if so,
42、 how many; g) the method used, i.e. method 7 of BS 4443-2:1988. 20+ 0 0+ 2 Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 08:48:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4443-2:1988 BSI 03-1999 Publications referred to BS 4443, Methods of test for flexible cellular materials1). BS 444
43、3-1:Method 1A, Method 1B and Method 1C, Measurement of dimensions of test specimens. BS 4443-1:Method 2, Determination of apparent density. BS 4443-1:Method 3A and Method 3B, Determination of tensile strength and elongation at break. BS 4443-1:Method 4, Measurement of cell count. BS 4443-1:Method 5A
44、 and Method 5B, Determination of compression stress-strain characteristics. BS 4443-1:Method 6A and Method 6B, Determination of compression set. BS 4443-3:Method 8, Determination of creep. BS 4443-3:Method 9, Determination of dynamic cushioning performance. BS 4443-4:Method 10, Determination of solv
45、ent swelling. BS 4443-4:Method 11, Humidity ageing at an elevated temperature. BS 4443-4:Method 12, Heat ageing. BS 4443-5:Method 13, Test for dynamic fatigue by constant load pounding. BS 4443-6:Method 14, Preparation of water extract. BS 4443-6:Method 15, Determination of tear strength. BS 4443-6:
46、Method 16, Determination of air flow value. BS 4443-7:Method 17, Determination of tear strength of flexible cellular material with an integral skin. ISO 2439, Polymeric materials, cellular flexible Determination of hardness (indentation technique). 1) Referred to in the foreword only. Licensed Copy:
47、 sheffieldun sheffieldun, na, Fri Dec 01 08:48:56 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 389 Chiswick High Road London W4 4AL | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
48、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporate
49、d by Royal Charter. Revisions British Standards are updated by amendment or revision. Users of British Standards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover. Tel: 020 8996 9000.
链接地址:https://www.31doc.com/p-3769833.html