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1、INTERNATIONAL STANDARD IS0 4672 Third edition 1997-03-O 1 Rubber and plastics hoses - Sub-ambient temperature flexibility tests Tuyaux en caoutchouc et en plastigue - Essais de souplesse B temp a=400net; p=iso; o=isocs; s=central Printed in Switzerland ii Copyright International Organization for Sta
2、ndardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 01:17:05 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD 0 IS0 IS0 4672: 1997(E) Rubber and plastics hoses - Sub-ambient temp
3、erature flexibility tests 1 Scope This International Standard specifies two methods for assessing whether a rubber or plastics hose retains adequate flexibility at sub-ambient temperatures. Method A is applicable to non-collapsible hose with a nominal bore up to and including 25. It measures the inc
4、rease in stiffness compared to the flexibility at a standard laboratory temperature. Method B is a simpler, qualitative method suitable for control testing and is applicable to hose with a nominal bore up to and including 100. 2 Normative references The following standards contain provisions which,
5、through reference in 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
6、applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 471 : 1995 Rubber - Temperatures, humidities and times for conditioning and testing. IS0 1402 : 1994 Rubber and plastics hoses and hose assemb
7、lies - Hydrostatic testing. IS0 3383 : 1985 Rubber - General directions for achieving elevated or subnormal temperatures for test purposes. 3 Method A - Sub-ambient temperature stiffness test 3.1 Bpparatus (see fi_rmre 1) 3.1.1 Torque wheel, having a diameter equal to twice the minimum bend radius s
8、pecified for the hose, provided with equipment for holding the hose tangential to the wheel, a suitable device to bend the hose around the wheel, and a strain gauge and graphical recorder to measure the torque with an accuracy of d is the hose bore. 3.2.2 Number At least three test specimens shall b
9、e used for each test. No test shall be carried out less than 24 h after manufacture of the hose. 3.3 nerature The test shall be conducted at one of the following temperatures: 0 “C + 2 “C -10 “C f 2 “C -25 “C f 2 “C -40 “C f 2 “C -55 “C f 2 “C or at any other sub-ambient temperature as defined in th
10、e relevant product standard. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 01:17:05 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 IS0 4672: 1997
11、(E) 3.4 Procedure Clamp one end of the test specimen (3.2) on the wheel (3.1. l), with the rest of the specimen straight. If the hose has natural curvature, this curvature shall follow that of the wheel. Without coolant in the container (3.1.2), determine the torque required to bend the test specime
12、n through 180” round the wheel at the standard temperature chosen from those given in IS0 47 1. The time for bending shall be 12 s + 2 s. Repeat the test with the container filled with coolant at the chosen test temperature (see 3.3). Condition the test specimen in a cold chamber at the test tempera
13、ture for 24 h, followed by conditioning at the test.temperature in the apparatus for at least 30 min before testing. 3.5 ression of results For each test specimen, calculate the mean torque at the standard temperature and the mean torque at the test temperature by calculating the mean of the peak va
14、lues contained in the central 50 % of the respective torque traces. Calculate the stiffness S, expressed as the ratio of the mean torque at the test temperature to that at the standard temperature, from the equation where r, is the torque at the test temperature (mean value from three tests); T, is
15、the torque at the standard temperature (mean value from the three tests). If the individual values for the three test specimens do not agree to within 15 % of the mean value at each temperature, the test shall be repeated. 3.6 Test report The test report shall include the following particulars: refe
16、rence to this International Standard; b) a full description of the hose and its origin; c) the dimensions of the test specimens; 4 the coolant used; 3 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not fo
17、r Resale, 04/25/2007 01:17:05 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 4672: 1997(E) e) the standard temperature and the test temperature; 0 the torque at the standard temperature and at the test temperature; g) the calculated value of the stiffness. 4 Method B -
18、 Cold bend test 4.1-l Mandrel, having an outside diameter equal to twice the minimum bend radius specified for the hose, or a former, with an arc of at least 180”. If the minimum bend radius is not specified, the mandrel or former shall have an outside diameter equal to 12 times the nominal bore of
19、the hose. 4.1.2 Conditioning chamber, capable of being maintained at the specified temperature (see 4.3). 4.2 The test specimen shall be cut from the hose under test and shall have a length adequate to provide a grip at each end in addition to a section which can be bent round the periphery of the m
20、andrel. The test specimen shall be discarded on completion of the test. 4.3 Test tew The test shall be conducted at one of the following temperatures: 0 “C f 2 “C -10 “C f 2 “C -25 “C f 2 “C -40 “C f 2 “C -55 “C f 2 “C or at any other sub-ambient temperature as defined in the relevant product standa
21、rd. 4.4 l?rocedu Condition the mandrel (4.1.1) and the test specimen (4.2) in the conditioning chamber (4.1.2) at the chosen test temperature (see 4.3) for 24 h. Without removing them from the conditioning chamber, bend round the mandrel hoses of up to and including 22 nominal bore through 180” in 1
22、0 s f 2 s and hoses of greater than 22 nominal bore through 90” in 10 s f 2 s. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 01:17:05 MDTNo reproduction or networking permitted
23、 without license from IHS -,-,- IS0 IS0 4672: 1997(E) For hoses of greater than 22 nominal bore, testing outside the conditioning chamber is permitted, but precautions shall be taken against an unacceptable increase in the temperature of the specimen during the test. Observe whether any cracking or
24、breaking of the hose lining or cover occurs. After bending, allow the test specimen to regain ambient temperature, and apply the specified proof test pressure, measured accurately in accordance with IS0 1402, to confirm whether or not any cracking or breaking of the lining or cover has occurred. 4.5
25、 Test report The test report shall include the following particulars: a) a reference to this International Standard; b) a full description of the hose and its origin; c) the dimensions of the test specimen; d) the test temperature; e) the results of the visual examination of the test specimen after
26、bending; f) the results of the visual examination after the proof pressure test; 8) a description of the test procedure. 5 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 01:17:0
27、5 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 4672: 1997(E) 0 IS0 Torque measuring device Roller for guiding Coolant container Torque wheel Test piece Set tion A -A Net for support of the hose Bearing - T _- A Test piece 7 A Anchor for end of hose Figure 1 - Apparat
28、us for method A 6 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 01:17:05 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 4672: 1997(E) IS0 ICS 23.
29、040.70 Descriptors: rubber products, plastics products, hoses, rubber hoses, plastics hoses, tests, low temperature tests, stiffness tests, bend tests, test equipment. Price based on 6 pages Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 01:17:05 MDTNo reproduction or networking permitted without license from IHS -,-,-