HG 2724.6-1995 Rubber Wire Test Method Heat Aging Test HG2724.6-1995 Standard Download Decompression Password: www.bzxz.net

Chemical Industry Standard of the People's Republic of China
HG/T 2724.6--1995
idtISo2321:1983
Test Methods for Rubber Threads
Heat Aging Test
Published on 1995-06-30bZxz.net
Ministry of Chemical Industry of the People's Republic of China
Implementation on 1996-01-01
This standard is formulated by adopting the fifteenth part of the international standard ISo2321:1983 "Rubber Threads-Test Methods", and is equivalent to it in terms of technical content and writing rules. By adopting international standards, formulating test methods suitable for rubber threads in my country, laying a foundation for formulating product standards in the future and adapting to the needs of international trade, technology and economic exchanges as soon as possible, this standard is proposed by the Technical Supervision Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is issued by the Latex Industry Research Institute of the Ministry of Chemical Industry. This standard was drafted by: Latex Industry Research Institute of the Ministry of Chemical Industry. The main drafters of this standard were Kang Ronghua, Wen Sizheng, and Xia Yingguang. 39
ISO Foreword
ISO (International Organization for Standardization) is a worldwide federation of national standards associations (ISO member groups). The work of formulating international standards is carried out through ISO technical committees: any group interested in the items established by the technical committee has the right to participate in the committee. All governmental and non-governmental international organizations that have relations with ISO can participate in this work. The draft international standards adopted by the technical committees should be sent to the member groups for approval before they can be approved as international standards by the ISO Council.
International Standard ISO2321 was prepared by ISO/TC45\Rubber and Rubber Products\Technical Committee. This second edition was submitted directly to the ISO Council in accordance with Section 6.11.2 of Part 1 of the ISO Technical Working Guidelines. The second edition replaces the first edition (ISO 2321:1975) and has been approved by the following national member bodies: Belgium
Bulgaria
Canada
Czechoslovakia
Federal Germany
Ireland
Israel
Italy
For technical reasons the following national members have expressed disapproval of this document: United States
Romania
This international standard also replaces Annex 1-1975, Annex 2-1980 and Annex 3-1980.40
1 Scope
Chemical Industry Standard of the People's Republic of China
Test methods for rubber threads
Heat aging test
This standard specifies the test method for heat aging of rubber threads. This standard applies to rubber threads made of natural rubber and synthetic polyisoprene rubber. 2 Reference standards
HG/T2724.6—1995
idt ISO 2321: 1983
The following standards contain provisions that constitute the provisions of this standard through reference in this standard. When the standard is published, the versions shown are valid. All standards will be revised. All parties using this standard should explore the possibility of using the latest version of the following standards. GB2941—91 Standard temperature for environmental conditioning and testing of rubber specimens. Humidity and time (ISO471: 1983, S0 1826: 1981) GB/T3512-83 (89) Rubber hot air aging test method (ISQ188: 1977) 3. Overview 3.1 Rubber aging test is usually carried out on a specimen that is not subjected to stress, so it has its limitations in evaluating the life of rubber thread. The rubber thread will continue to extend during use. 3.2 This test can show the degree of deterioration of the rubber thread. When the rubber thread is kept at a constant length under conditions that are more severe than the use, the retention rate of the specified physical properties is measured. 3.3 This test is only of comparative significance, and the test results cannot be linked to the actual life of the thread. 4 Principle 4.1 Use appropriate test methods to measure a selected physical property of the rubber thread. Select a specimen from the various samples, maintain 100% elongation, age in a circulating hot air oven, and then measure the selected physical properties and record the percentage maintained. 4.2 The physical properties selected for the test may be any of the tensile strength, elongation at break, elongation under constant load, Schwartz value and stress retention rate. The most suitable are Schwartz value or stress retention rate. 5.1 The test apparatus shall comply with the requirements of the selected physical property test method. 5.2 The fixture shall be able to keep the specimen at 100% elongation. Low thermal expansion and low heat capacity materials shall be used to reduce dimensional changes during heating and local overheating at the contact point with the rubber wire. In particular, metal materials such as steel or magnesium shall not be used. 5.3 The circulating hot air oven shall comply with the requirements of GB/T3512. 6 Test steps
6.1 Use appropriate test methods and take a specified number of samples to determine the initial values ​​of physical properties. Approved by the Ministry of Chemical Industry of the People's Republic of China on June 30, 1995 and implemented on January 1, 1996
HG/T 2724.6—1995
6 1.1 If the Schwartz value is measured, the maximum pre-elongation should be 300% to avoid excessive damage to the sample during the pre-elongation period after aging.
6.1.2 If the stress retention rate is measured, the rubber wire should be pre-elongated to 300% and cycled for six times before being stretched to 100% for measurement.
6.2 Mount the sample with 100% elongation on the fixture and leave it for 60±10min under the conditions specified in GB2941. 6.3 Place the sample mounted on the fixture in a circulating hot air oven and age it under the conditions specified in Table 1. Before the sample is loaded, the temperature of the oven should be stabilized at the test temperature.
Table 1 Aging conditions
Test classification
A (conventional)
B (heat-resistant)
Note: Test B is used for rubber wire heat resistance classification. Temperature ()
100± 1
150 ±2
Time (n)
Precautions should be taken to ensure that the temperature does not drop sharply when the sample is loaded. An oven with high heat capacity should be used and the test chamber should be placed in the oven for the shortest time.
6.4 Remove the sample from the oven and place it for more than 16 hours according to the provisions of GB2941. 6.5 Re-determine the selected physical properties according to the method used before aging. If the sample is damaged at the bundling point of the misaligned bowl, the test should be repeated.
7 Result expression
The retention percentage of the initial value of the selected physical property is calculated by the following formula: X.
Where: X. — is the performance value before aging;
X—— is the performance value after aging,
the median value of the test result is taken.
Test report
The test report should include the following contents:
Full description of the test partner and its source:
Based on the standard;
Selected physical properties, test methods and test equipment used; aging time and temperature;
Percentage and initial value of physical properties retained: test results;
Test date;
Tester.
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