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1、A Reference number ISO 15853:1999(E) INTERNATIONAL STANDARD ISO 15853 First edition 1999-12-01 Thermoplastics materials Preparation of tubular test pieces for the determination of the hydrostatic strength of materials used for injection moulding Matires thermoplastiques Prparation dprouvettes tubula
2、ires pour la dtermination de la rsistance la pression hydrostatique des matires destines au moulage par injection Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Aramco HQ/9980755100 Not for Resale, 04/23/2007 09:20:00 MDTNo reproduction or ne
3、tworking permitted without license from IHS -,-,- ISO 15853:1999(E) ISO 1999 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in w
4、riting from the publisher. International Organization for Standardization Case postale 56 CH-1211 Genve 20 Switzerland Internetisoiso.ch Printed in Switzerland ii ContentsPage 1 Scope1 2 Normative references1 3 Terms and definitions .2 4 Apparatus.2 4.1 Mould .2 4.2 Injection-moulding machine2 5 Tes
5、t pieces .4 5.1 General.4 5.2 Injection-moulded test pieces.4 5.3 Extruded test pieces.5 6 Injection-moulding process5 7 Characteristics of the injection-moulded test pieces 6 7.1 General.6 7.2 Appearance .6 7.3 Dimensions6 7.4 Oven test6 7.5 Crushing test.6 7.6 Test piece production report.6 Copyri
6、ght International Organization for Standardization Provided by IHS under license with ISO Licensee=Aramco HQ/9980755100 Not for Resale, 04/23/2007 09:20:00 MDTNo reproduction or networking permitted without license from IHS -,-,- ISOISO 15853:1999(E) iii Foreword ISO (the International Organization
7、for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has t
8、he right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Interna
9、tional Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the memb
10、er bodies casting a vote. International Standard ISO 15853 was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for the transport of fluids, Subcommittee SC 5, General properties of pipes, fittings and valves of plastic materials and their accessories Test methods and
11、basic specifications. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Aramco HQ/9980755100 Not for Resale, 04/23/2007 09:20:00 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 15853:1999(E) ISO iv Introduction This
12、 International Standard specifies a method of preparing, by injection-moulding (see the note to clause 1), tubular test pieces for the determination of the long-term behaviour of their constituent material. Unlike the case of pipes, it is difficult to evaluate the resistance to internal pressure of
13、injection-moulded piping components such as fittings or valve bodies. In fact, the material properties determined would be falsified for various reasons, such as the heterogeneity of any strain in the product; the fact that the product is shaped (e.g. tees, elbows); the presence of weld lines and, s
14、ometimes, an injection point. It is therefore necessary to use test pieces injection-moulded in the form of a tube in order to be able to study the time-related behaviour under internal hydrostatic pressure of the compounds used for injection-moulding, as is done in the case of the pipes. Test piece
15、s produced in this way have a regular shape and uniform thickness without any weld lines, and the stresses induced in their walls are well defined. This allows them to be subjected to the same test methods as pipes, including ISO 1167 for the determination of the resistance to internal pressure; ISO
16、 9080, or a similar method of extrapolation of hydrostatic stress rupture data, to determine the long-term hydrostatic strength of thermoplastics pipe materials; ISO 12162 for the determination of the MRS (minimum required strength) and the classification of the material. However, the properties of
17、the test pieces, and hence the measured values obtained, depend largely on the conditions of processing of the material. This means that the conditions of production must be harmonized in order to make the test pieces reproducible. For this, the main parameters of the moulding procedure have to be d
18、efined. On the other hand, the determination of the basic characteristics of the material requires very long and expensive testing. It is therefore important to have test pieces exempt from failures which could affect the test results. Checks should be carried out to verify, in particular, the degre
19、e of latent internal strain and the extent of any thermal degradation which may occur during processing. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Aramco HQ/9980755100 Not for Resale, 04/23/2007 09:20:00 MDTNo reproduction or networking
20、permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISOISO 15853:1999(E) 1 Thermoplastics materials Preparation of tubular test pieces for the determination of the hydrostatic strength of materials used for injection moulding 1 Scope This International Standard specifies a general proced
21、ure for the production, by injection-moulding, of tubular test pieces for the determination of the resistance to internal pressure. It also specifies the design of the mould to be used. By using the same material as for injection-moulded piping components, such as fittings, these test pieces make it
22、 possible to determine the time-related behaviour of the fitting material under hydrostatic pressure and under the very same conditions as specified for extruded pipes. It is possible to test the resistance to internal pressure of the injection-moulded tubular test pieces in accordance with ISO 1167
23、, to extrapolate the results in accordance with a method such as that specified in ISO 9080 in order to determine the MRS, and to classify the material in accordance with ISO 12162. The tubular test pieces also make it possible to verify individual points on previously established stress/time regres
24、sion curves as a minimum material test requirement. The basis established by this International Standard allows test pieces to be prepared reproducibly. Nevertheless, the method given is a general one, and the injection-moulding parameters have to be specified for every material used. NOTE If the co
25、mpound used for the injection-moulding of piping components can also be extruded, then its time-related behaviour may be investigated using either injection-moulded or extruded tubular test pieces. 2 Normative references The following normative documents contain provisions which, through reference i
26、n this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most r
27、ecent editions of the normative documents indicated below. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 294-1:1996, Plastics Injection-moulding of test specimens of thermoplastic materials Part 1: General principles, and moulding of multipurpose and bar t
28、est specimens. ISO 580:1), Injection-moulded unplasticized poly(vinyl chloride) (PVC-U), chlorinated poly(vinyl chloride) (PVC-C), acrylonitrile-butadiene-styrene (ABS) and acrylonitrile-butadiene-acrylester (ABA) fittings Behaviour to heat Oven and liquid-bath methods. ISO 1167:1996, Thermoplastics
29、 pipes for the conveyance of fluids Resistance to internal pressure Test method. 1) To be published. (Revision of ISO 580:1990) Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Aramco HQ/9980755100 Not for Resale, 04/23/2007 09:20:00 MDTNo repr
30、oduction or networking permitted without license from IHS -,-,- ISO 15853:1999(E) ISO 2 ISO 3126:2), Plastics piping systems Plastics piping components Measurement and determination of dimensions. ISO 9080:3), Plastics piping and ducting systems Determination of the long-term hydrostatic strength of
31、 thermoplastics materials in pipe form by extrapolation. ISO 9853:1991, Injection-moulded unplasticized poly(vinyl chloride) (PVC-U) fittings for pressure pipe systems Crushing test. ISO 12162:1995, Thermoplastics materials for pipes and fittings for pressure applications Classification and designat
32、ion Overall service (design) coefficient. 3 Terms and definitions For the purposes of this International Standard, the terms and definitions given in clause 3 of ISO 294-1:1996 apply. 4 Apparatus 4.1 Mould For the fabrication of injection-moulded test pieces, a single-cavity mould shall be used. Fig
33、ure 1 shows an example of a single-cavity mould and Figure 2 shows the corresponding test pieces. The mould shall be end-gated and the sprue diameter at the nozzle side shall be at least 5 mm. The heat-transfer system of the mould shall be designed so that temperature differences between any points
34、along the edge of the mould or on the surface of the cavity are less than 5 C. Machining tolerances for the cavity itself will depend upon the material to be moulded. The diameter of the test pieces shall remain within 0,2 mm. 4.2 Injection-moulding machine 4.2.1 Use an automatic reciprocating-screw
35、 injection-moulding machine equipped with all the necessary devices for control of the moulding conditions (see 4.2.5). 4.2.2 The mould-closing force shall be high enough to prevent the formation of excessive flash under any operating conditions. 4.2.3 The screw shall be of a type (e.g. diameter, le
36、ngth, thread height, compression ratio) suitable for use with the injection-moulding material concerned. It is recommended that a screw with a diameter in the range between 18 mm and 40 mm be used (see ISO 294-1). 4.2.4 The ratio of the screw stroke volume to the shot volume shall, in general, not b
37、e less than 1:10 or more than 1:2 (i.e. between 10 % and 50 % volume efficiency). With thermally sensitive thermoplastics, a lower ratio may be required. The ratio shall not be so high, however, that crosslinking starts. 2) To be published. (Revision of ISO 3126:1974) 3) To be published. (Revision o
38、f ISO/TR 9080:1992) Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Aramco HQ/9980755100 Not for Resale, 04/23/2007 09:20:00 MDTNo reproduction or networking permitted without license from IHS -,-,- ISOISO 15853:1999(E) 3 Key 1Heat-transfer fl
39、uid inlets and outlets5Guide pins 2Lubrication holes6Ejection pins 3Mould7Direction of injection 4Core NOTE The moulding is ejected in two steps, as follows: a) parts 8 and 9 move away from plane B, together with the moulding, until the ejection pins are stopped (the moulding breaks off at the sprue
40、); b) part 9 moves away from plane A until the moulding drops out. Figure 1 Example of a single-cavity mould Dimensions in millimetres Figure 2 Injection-moulded test piece (dn = 50, pipe series S6,3) Copyright International Organization for Standardization Provided by IHS under license with ISO Lic
41、ensee=Aramco HQ/9980755100 Not for Resale, 04/23/2007 09:20:00 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 15853:1999(E) ISO 4 4.2.5 The control system shall be capable of maintaining the operating conditions within the following ranges: injection pressure 3 %; inje
42、ction time 0,05 s; hold pressure 5 %; hold time 5 %; melt temperature 3 C; mould temperature 3 C up to 80 C; 5 C above 80 C; shot mass 1 %. 4.2.6 A calibrated needle-probe pyrometer accurate to 1 C shall be used to measure the temperature of the melt. A calibrated surface pyrometer accurate to 1 C s
43、hall be used to measure the temperature of the surface of the mould cavity. 5 Test pieces 5.1 General The tubular injection-moulded or extruded test pieces are for use in the hydrostatic pressure test specified in ISO 1167. 5.2 Injection-moulded test pieces Injection-moulded test pieces shall have o
44、ne end closed, as shown in Figure 3. NOTE Injection-moulded test pieces with a longitudinal weld line and both ends open should preferably be used for comparative and investigative purposes only. The nominal outside diameter dn of the test pieces shall be between 25 mm and 110 mm inclusive. The wall
45、 thickness will depend on the material concerned. The free length l0 of the test pieces, excluding the ends, shall be 3dn, except for test pieces with dn = 50, for which the minimum length shall be 140 mm. Figure 3 Test pieces produced by injection-moulding (upper test piece) and extrusion (lower te
46、st piece) Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Aramco HQ/9980755100 Not for Resale, 04/23/2007 09:20:00 MDTNo reproduction or networking permitted without license from IHS -,-,- ISOISO 15853:1999(E) 5 5.3 Extruded test pieces Extrud
47、ed test pieces shall have both ends open, as shown in Figure 3, and shall be capped afterwards for the subsequent pressure test. Test pieces may be obtained from an extruded pipe. The nominal outside diameter dn of the test pieces shall be between 25 mm and 110 mm inclusive. The wall thickness will
48、depend on the pipe series for the material concerned. The free length l0 of the test pieces, excluding the extremities, shall be 3dn, with a minimum of 250 mm. 6 Injection-moulding process If necessary, the material shall be conditioned prior to processing. Adjust the moulding conditions until the mouldings are free of sink marks, voids and other faults and have minimum flash. Keep the injection velocity low to allow for t