This standard specifies the test equipment, sample preparation, test steps, test results and calculations for the salt bath test. This standard is applicable to testing the waterproof performance of the tape-type wrapping layer on the metal sheath of the cable. GB/T 2951.26-1994 Test methods for mechanical and physical properties of wires and cables Salt bath test GB/T2951.26-1994 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test method for determining mechanical and physical properties of electric cables and wiresSallne bath test
1 Subject content and applicable scope
GB/T 2951.26-94
Replaces GB 2951. 26-82bzxz.net
This standard specifies the test equipment, sample preparation, test procedures, test results and calculations for the salt bath test. This standard is applicable to testing the waterproof performance of the tape-shaped wrapping layer on the metal sheath of the cable. This standard is not applicable to general covering layers composed of linen yarn, linen cloth, paper, cotton cloth and glass yarn. The general provisions, definitions and regular calibration of the test equipment for the mechanical and physical properties of wires and cables are specified in GB/T2951.1. 2 Reference standards
GB/T2951.1-94 Test methods for mechanical and physical properties of wires and cables General GB/T2951.23-94 Test methods for mechanical and physical properties of wires and cables Bending test GB/T3048.5-94 Test methods for electrical properties of wires and cables Insulation resistance test 3 Test equipment
Salt bath test device, as shown in Figure 1.
Figure 1 Salt bath test device
1—· Cable sample: 2—0.5% salt water solution, 3—Salt bath; 4 Electrode R Specified bending radius Approved by the State Administration of Technical Supervision on July 7, 1994 and implemented on January 1, 1995
4 Sample preparation
CB/T 2951.26--94
4.1 Sampling Take 3 samples of the same type, and the length of each sample should be at least 5 times the diameter of the cylinder specified for the bending test. 4.2 Perform bending test on cable samples according to the method and number specified in GB/T2951.23. 5 Test steps
5.1 Bend the cable sample after bending test into a U shape and place it at the bottom of the salt bath tank. Inject 0.5% salt water solution into the tank, and its depth should be not less than 500mm. The length of the cable sample exposed to the solution surface should be not less than 300mm. Apply 10V DC voltage between the bath and the metal sleeve, and the gold sleeve is connected to the negative pole of the DC power supply. This voltage should be maintained until the end of the entire test. 5.2 After the sample is immersed in the salt solution for 24 hours, the insulation resistance of the cable outer sheath for the first 1 minute should be measured at 25±2℃. 5.3 Subsequently, the sample should be subjected to 100 thermal cycles, each of which should include heating the salt solution to 65±5℃, maintaining this temperature for 5 hours, and cooling the solution to a temperature not higher than 30℃ for the remaining time of the 24 hours. 5.4 During the test, the insulation resistance of the cable sheath can be monitored periodically. The temperature of the salt solution during the test should not be higher than 30'C. Under normal circumstances, a cycle of 7 days can be used. 5.5 After the last thermal cycle is completed, the insulation resistance of the cable outer sheath should be measured again at a temperature of 25±2℃. 6 Test results and calculations
6.1 After 100 thermal cycle tests, the product of the insulation resistance R measured at 25±2℃ and the surface area A of the waterproof layer submerged in the salt solution should not be less than 10'Ma·cm. Ro 10*MQ -cm\
Where: R1a—insulation resistance of the outer sheath of the sample at 25±2℃ after 100 thermal cycle tests, MQ; A—surface area of ​​the waterproof layer immersed in the salt solution, cm; A—dimensional DL: D—outer diameter of the waterproof layer. cm;
L——length of the waterproof layer immersed in the salt solution, cm. 6.2 After 100 heat cycle tests, the corrosion on the surface of the metal sleeve of the sample should be level 0 in Table 1. Table 1
Corrosion level
No corrosion, no visible corrosion on the surface Light corrosion, visible slight corrosion spots Moderate corrosion, obvious local fan corrosion or large area corrosion, the maximum corrosion depth is less than half of the thickness Severe corrosion, the maximum corrosion depth is greater than half of the thickness or there are perforations, cracks and other strong corrosion 6.3 After 100 heat cycle tests, the waterproof tape should not crack when folded in half by hand at room temperature. 7 Notes
7.1 The insulation resistance of the cable outer sheath should be tested in accordance with the provisions of GB/T3048.5. The test voltage should not be less than 100V. It is allowed to use other instruments for direct reading test, but this method should be used when arbitration. 7.2 In the periodic test of the test process, if the situation is lower than the indicators specified in Article 6.1, it should be judged as unqualified and the test will not continue.
7.3 When testing insulation resistance, the 10V DC voltage applied to the sample should be temporarily removed. 7.4 When the heating test is stopped for some reason, the sample shall not be removed from the salt bath, and the stop time shall not be counted.
GB/ 951.26-94
This standard was proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard is under the jurisdiction of the Shanghai Cable Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Shanghai Cable Research Institute of the Ministry of Machinery Industry. The main drafter of this standard is the film.
This standard was first issued in 1982 and revised for the first time in July 19
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