This standard specifies the test equipment, sample preparation, test steps, test results and calculations for the oxidation induction period test. This standard determines the thermal migration performance of the sample by measuring the time when the sample begins to undergo autocatalytic oxidation reaction under high temperature oxygen conditions. It is applicable to polyolefin insulation and sheath materials for wires and cables. GB/T 2951.37-1994 Test method for mechanical and physical properties of wires and cables Oxidation induction period test GB/T2951.37-1994 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test method for deoxidizing mechanical properties of electric cables antl wiresTest for oxidative inductive tinne1Subject content and scope of application
GB/T2951.3794
Replaces GB2951.37--83
This standard specifies the test equipment, sample preparation, test steps, test results and calculations for the oxidation induction period test. This standard is used to determine the thermal stability of the sample by measuring the time when the sample begins to undergo autocatalytic oxidation reaction under high temperature oxygen conditions. It is applicable to polyolefin insulation and sheath materials for wires and cables. The definition of the first section of the mechanical and physical properties test of wires and cables and the periodic calibration of the test equipment are stipulated in GB/T2951.1. 2 Reference standards
GB/T2951.1-94 General rules for test methods of mechanical and physical properties of wires and cables 3 Test equipment
3.1 Knife single-sided blade or double-sided blade.
3.2 Thermal analyzer CDR-1 differential thermal analyzer or CRY1 differential thermal analyzer or other similar thermal analyzers. 3.3 Analytical balance with an accuracy of 0.1mg.
3.4 ​​Sample cup $5mm×2.5mm aluminum cup, which should be cleaned in advance with diacetyl (not less than CP grade). 4 Sample preparation
Before sampling, the cable insulation and sheath at the sampling position should be wiped clean with alcohol, and then on the outer surface of the cable insulation or sheath at three different positions, cut about 1mm×1iam×0.5mm granular or about 0.2mm thick sheet samples, or take the whole piece of insulation or sheath and cut it into samples of the above size.
5 Test steps
5.1 Place the aluminum cup with 5±0.1Ing sample and the empty lead cup (4~5mg α-alumina can also be placed) on the sample holder of the thermal analyzer.
5.2 Pass dry industrial nitrogen with a flow rate of 200±10mL/min. Then heat to 200±0.5℃ at a rate of 10℃/min. Keep the temperature for 5min,
5.3 Quickly switch the gas with 7 industrial oxygen. The oxygen flow rate should be maintained at 200 ± 10 mL/min. 5.4 The moment of oxygen switching is the start time of the sample induction period, and a mark is made on the record paper. 5.5 When the baseline deviates significantly, as shown in Figure 1, the test is terminated. Approved by the State Bureau of Technical Supervision on July 7, 1994 and implemented on January 1, 1995
N,2ul : 11mL/min
External temperature at min rate
2c constant temperature for 5min
GB/T 2951.37-94
0,200±lumL/min
2.n: I induction period (min)
Figure 1 Schematic diagram of differential thermal spectrum of polyethylene
6 Test results and calculation
The point where the oxidation induction period starts to deviate from the baseline
6.1 The point in Figure 1 that starts to deviate significantly from the baseline is the end point of the oxidation induction period. Measure the distance S between the start point and the end point of the oxidation induction period. 6.2 The oxidation induction period is calculated as follows:
Where: T—oxidation induction period, mi;
S—distance quotient between the start and end points of the oxidation induction period, mm; V—recording paper speed, mm/min.
6.3 The test results are the arithmetic mean of the test results of three samples. Additional remarks:
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 Xu Ruihao. wwW.bzxz.Net
This standard was first issued in 1983 and revised for the first time in July 1994.
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