GB/T 2423.34-1986 Basic environmental test procedures for electrical and electronic products Test Z/AD: Temperature/humidity combined cycle test method
Some standard content:
1 Introduction
National Standard of the People's Republic of China
Basic environmental testing procedures for electric and electronic products Test Z/AD: Temperature/humidity combination
Cyclic test method
Basic environmental testing
procedures for electric and electronic products Test Z /AD: Composite temperature/humidity cyclic test
GB 2423.34--86
This standard is equivalent to the international standard IEC68-2-38 (1974, first edition) "Test Z/AD: Temperature/humidity combination cyclic test".
This standard should be used together with the following standards: GB2421-81 "General Principles of Basic Environmental Test Procedures for Electrical and Electronic Products" GB2422-81 "Terms and Terms of Basic Environmental Test Procedures for Electrical and Electronic Products" GB2424.2-81 "Guidelines for Humidity Tests for Basic Environmental Test Procedures for Electrical and Electronic Products" This standard is mainly applicable to temperature/humidity combination tests of components, and its purpose is to use accelerated methods to determine the ability of test samples to withstand high temperature, high humidity and low temperature degradation.
This test is different from other damp heat tests because the following points increase the severity of the test: a. There are many temperature changes or "breathing" effects within a given time, b. A large cycle temperature range;
c. A large temperature change rate,
d. Including multiple temperature changes below 0°C. This test is a temperature cycle under high humidity, and a "breathing" effect is produced, allowing water vapor to enter an incompletely sealed container. It includes a low temperature test stage to determine the effect of periodic icing on the test sample. Therefore, the effect of accelerating "breathing" and freezing the water vapor absorbed in cracks and fissures is the basic feature of this test. Application of the test:
For the reasons mentioned above, it is recommended that this test be limited to component samples when the structure of the test sample presents the "breathing" effect of the damp heat test combined with freezing and whose thermal characteristics are compatible with the temperature change rate of this test. For solid test samples, such as test samples of plastic packages, there may be fine linear cracks or porous materials, where the absorption or diffusion of water vapor plays a dominant role, it is best to use the steady-state damp heat test Ca. For large test samples, such as equipment or components that must ensure temperature stability at each stage of the cycle, the alternating damp heat test Db should be used. In this case, test Db should generally form part of the "standard climate sequence" specified in Chapter 6 of GB2421--81. As with other damp heat tests, this test can apply polarizing voltage or electrical load to the test sample. In the case of applying electrical load, the conditions of the test chamber shall not be affected by the increase in temperature of the test sample. As can be seen from the above, this test is not interchangeable with the steady damp heat test or the alternating damp heat test and cannot be used as a replacement test for them. The choice of test procedure should take into account the physical properties and thermal characteristics of the test sample and the types of failure mechanisms that are important in each special case. Issued by the National Bureau of Standards on July 31, 1986
Implementation on August 1, 1987
2 Test Equipment
GB 2423.34—86
The test samples are exposed to damp heat and then to low temperature conditions. This can be done in one test chamber or two test chambers. 2.1 The damp heat test chamber shall meet the following requirements: 2.1.1 The temperature shall be able to rise or fall between 25±2℃ and 65±2℃ within 1.5 to 2.5 hours. 2.1.2 During constant temperature or heating period, the relative humidity shall be maintained at 93±3%, and during cooling period, it shall be maintained at 80% to 96%. 2.1.3 The temperature and humidity at each point in the working space shall be uniform and as close as possible to the conditions near the monitoring point. Box The air in the chamber should be stirred continuously at a constant rate to maintain the specified temperature and humidity conditions. Note: During the constant temperature period, the temperature tolerance of ±2°C includes the absolute error of measurement, the slow change of temperature and the temperature difference in the working space. In order to maintain the required humidity, the temperature difference between any two points in the working space should not exceed 1°C during the constant temperature period. Short-term fluctuations in temperature should also be kept within a small range.
2.1.4 The test specimens should not be affected by radiant heat during the test. 2.1.5 The resistivity of the water used to maintain the humidity of the test chamber shall not be less than 50092·m. 2.1.6 Condensed water must be continuously Continuously discharged from the box, can not be used without purification. 2.1.7 It should be ensured that the condensed water on the box wall and the top of the box does not drip onto the test sample. 2.2 The low temperature test chamber should meet the following requirements: . 2.2.1 The temperature can be maintained at ~10±2℃.
2.2.2 The temperature at each point in the working space should be uniform and as close as possible to the conditions near the monitoring point. The air in the box should be stirred continuously to maintain the specified temperature conditions. 2.2.3 It should be noted that the heat capacity of the test sample cannot significantly affect the conditions in the box. 2.3 The wet heat test chamber used for low temperature testing, in addition to meeting 2. In addition to the requirements of Article 1, the following provisions must also be met: 2.3.1 The temperature can be reduced from 25±2℃ to -10±2℃ within a period not exceeding 30min. 2.3.2 When there is a test load, the temperature in the box can be maintained at -10±2℃ for 3h. 2.3.3 The temperature can be increased from -10±2℃ to 25±2℃ within a period not exceeding 90min. 3 Severity level
Unless otherwise specified, 10 cycles should be performed, each cycle lasting 24h. If it is not 10 cycles, the number of cycles and the specific position of the low temperature cycle in the sequence should be specified in the relevant standards. 4 Test procedure
4.1 Pretreatment (see Figure 1)
Unless otherwise specified, before the first damp heat test cycle, the test sample should be placed in the "dry standard conditions" specified in Article 4.5 of GB2421--81 (55±2℃, relative humidity not exceeding 20%) for 24h without packaging, without power supply, and ready for use. Then, the test sample is allowed to reach temperature stability before the initial test under normal test atmosphere conditions or under conditions specified in relevant standards. 337
4.2 Initial test
Relative pressure
Not more than 20%
Drying time
GB 2423.34-86
No cooling rate specified
Pretreatment time
Stabilization time
Figure 1 Pretreatment
Time (h)
Initial test
Time (h)
According to relevant standards, the test sample shall be inspected for appearance and tested for electrical and mechanical properties. 4.3 Condition test
4.3.1 The test sample shall be placed in the wet heat test chamber in the normal working position or in the state specified in relevant standards without packaging, without power supply and in a state ready for use, and shall be subjected to 10 temperature/humidity cycles, each cycle lasting 24 hours. During any five of the first nine cycles, the test specimens shall be subjected to the low temperature cycle after being exposed to the damp heat sub-cycle (sections a to f of Figure 2a).
4.3.2 This test may be conducted in the same test chamber (one chamber method) or in two test chambers (two chamber method). If the high temperature/high humidity and low temperature sub-cycles are conducted in two test chambers, the test specimens shall not be subjected to thermal shock unless it is known that the test specimens are insensitive to this degree of thermal shock.
GB 2423.34---86
If a batch of test specimens is subjected to such thermal shock by the two chamber method and shows obvious failure, a batch of test specimens shall be retested under temperature ramping conditions. If no obvious failure occurs under these test conditions, these test specimens shall be considered to have successfully passed the test.
4.3 The remaining four cycles of the first nine cycles shall not include low temperature (see Item 4.3.4.3 and Figure 2b). 4.3.4 Description of 24h cycle
4.3.4.1 Description of temperature/humidity sub-cycle (applicable to all cycles, see Figures 2a and 2b) At the beginning of each 24h cycle, the temperature of the test chamber should be controlled at 25±2℃ and the relative humidity should be 93±3%. msgg
* The time tolerance at this point is ±5min. 15
Conditional test
Uncontrolled
Relative humidity
182022
Time (h)
Preferred range
Allowable range
Preferred range
Allowable range
Figure 2a Exposure to damp heat followed by exposure to low temperature, time (h)
GB2423.34—86
Conditional test
18202224
161820 22 24
Figure 2b After exposure to damp heat, the temperature of the test chamber is between 1.5 and 2.Within 5 hours, it should be continuously raised to 65±2℃. a.
During this period, the relative humidity should be maintained within the range of 93±3%. Time (h)
Time (h)
b. Within 5.5 hours after the start of the cycle, the temperature and relative humidity in the chamber should be maintained at 65±2℃ and 93±3% respectively. c. Then the temperature of the test chamber should be reduced to 25±2℃ within 1.5~2.5 hours. During this period, the relative humidity should be maintained within the range of 80%~96%. d. Starting from 8 hours after the start of the cycle, the temperature of the test chamber should be continuously raised to 65±2℃ within 1.5~2.5 hours. During this period, the relative humidity should be maintained within the range of 93±3%. e. The temperature and relative humidity in the chamber should be maintained at 65±2℃ and 93±3% respectively until 13.5 hours after the start of the cycle. f. Then the temperature of the test chamber should be reduced to 25±2℃ within 1.5~2.5 hours. During this period, the relative humidity should be maintained within the range of 80% to 96%. 340
GB2423-34--86
g. The temperature in the chamber continues to be stable at 25±2℃ and the relative humidity at 93±3% until the low temperature sub-cycle begins or the 24h cycle ends. 4.3.4.2 Instructions for low temperature sub-cycle
Applicable to any 5 cycles of the first 9 cycles (see Figure 2a). a. After completing the temperature/humidity sub-cycle (see a to f in Figure 2a), the test chamber should be maintained at a temperature of 25±2℃ and a relative humidity of 93±3% for at least 1 hour but not more than 2 hours. b. Then reduce the chamber temperature to expose the test sample to low temperature. If the two-chamber method is used, move the test sample from the damp heat chamber to another low temperature chamber for low temperature exposure test, and complete the conversion within 5 minutes.
The temperature in the chamber shall begin to decrease 17.5 hours after the start of the cycle and reach -10±2°C within 18 hours after the start of the cycle. c. Starting 18 hours after the start of the cycle, the temperature shall be maintained at ~10±2°C for 3 hours. No relative humidity requirements are specified during the entire low-temperature sub-cycle. d. The temperature in the chamber shall begin to increase 21 hours after the start of the cycle and reach 25±2°C within 22.5 hours after the start of the cycle (see Figure 2a). If the two-chamber method is used, the test sample is moved from the low-temperature chamber to the wet heat chamber and the conversion is completed within 10 to 15 minutes. e. The temperature in the chamber shall be maintained at 25±2°C until the end of the 24-hour cycle. During this period, the relative humidity shall be maintained within 93±3%. 4.3.4.3 The instructions for the 24-hour cycle without low-temperature exposure apply to the remaining 4 cycles of the first 9 cycles (see Figure 2b). After the temperature/humidity subcycle, the cycle, excluding the low temperature subcycle, is the same as that specified in 4.3.4.1, except that in section g the test chamber shall be maintained at a temperature of 25 ± 2 °C and a relative humidity of 93 ± 3% until the end of the 24 h. 4.3.4.4 Instructions for the final cycle
After the last cycle is completed, the test chamber shall be maintained at a temperature of 25 ± 2 °C and a relative humidity of 93 ± 3% for 3.5 h and then the final test shall be carried out.
4.4 Final test
Final test of the test specimens may be carried out under the following conditions as specified in the relevant standards. 4.4.1 Tests at high humidity
Tests at high humidity shall be carried out during the last 2 h of the 3.5 h period mentioned in 4.3.4.4. It should be understood that many tests carried out under high humidity conditions cannot be directly compared with the results of the initial test or the test specimens after removal from the test chamber. The relevant standards should specify special precautions that must be observed when testing under high humidity conditions, including, when necessary, the method used to remove surface water droplets from the test specimens. After the test is completed, the test sample should be removed from the test box. 4.4.2 After the test is completed immediately after the test sample is removed from the test box, the test sample should be removed from the box and kept under normal test atmospheric conditions. If the initial test is not carried out under normal test atmospheric conditions, this test and the initial test should be carried out under the same environmental conditions.
Within 1 to 2 hours after the test sample is removed from the test box, the electrical and mechanical properties should be tested. If there is any objection to the results of the initial test during this period, it can be repeated once at the end of this period, and the results measured at the later period will be used as the basis for determining failure.
4.4.3 After the recovery test
As soon as the last cycle is completed, the test sample should be removed from the box and kept under normal test atmospheric conditions for 24 hours. If the initial test is not carried out under normal test atmospheric conditions, this test and the initial test should be carried out under the same environmental conditions.
The test can be carried out within 24 hours. If there is any objection to the test results, the test can be carried out at the end of 24 hours, and the measured results can be used as the basis for determining failure.
Details to be specified when adopting this standard
GB 2423.34--86
The state of the test sample during the conditioning test (such as electrical, mechanical load or polarization voltage), pretreatment procedures different from the "dry standard conditions"; b.
Initial test conditions different from normal test atmospheric conditions, electrical and mechanical performance tests that must be performed before the conditioning test; d.
If necessary, electrical and mechanical performance tests during the conditioning test and the time of the tests, e.
Electrical and mechanical performance tests after the conditioning test, the parameters to be tested first, and the time to complete the tests of these parameters different from this standard.
Additional remarks:
This standard was proposed by the National Technical Committee for Standardization of Environmental Conditions and Environmental Testing for Electrical and Electronic Products. This standard was drafted by the Working Group on Temperature/Humidity Combined Cycle Test Method. The main drafter of this standard was Nie Guocai.The last 2 hours of the 5-hour period are tested at high humidity. It should be understood that many tests conducted under high humidity conditions cannot be directly compared with the results of the initial test or the test results after the test sample is removed from the test chamber. The relevant standards should specify special precautions that must be followed when conducting tests under high humidity conditions, including, when necessary, the method used to remove surface water droplets from the test sample. After the test is completed, the test sample should be removed from the test chamber. 4.4.2 After the test is completed immediately after the test sample is removed from the test chamber, the test sample should be removed from the chamber and maintained under normal test atmospheric conditions. If the initial test is not conducted under normal test atmospheric conditions, this test should be conducted under the same environmental conditions as the initial test.
Within 1 to 2 hours after the test sample is removed from the test chamber, electrical and mechanical properties tests should be conducted. If there is any objection to the results of the initial test during this period, it can be repeated once later in this period, and the results of the later test will be used as the basis for determining failure.
4.4.3 Test after recoverybzxZ.net
After the last cycle is over, the test sample should be taken out of the box and kept under normal test atmospheric conditions for 24 hours. If the initial test is not carried out under normal test atmospheric conditions, this test and the initial test should be carried out under the same environmental conditions.
The test can be carried out within 24 hours. If there is any objection to the test result, the test can be carried out at the end of 24 hours, and the measured result can be used as the basis for determining failure.
Details to be specified when adopting this standard
GB 2423.34--86
The state of the test sample during the conditioning test (such as electrical, mechanical load or polarization voltage), pretreatment procedures different from the "dry standard conditions"; b.
Initial test conditions different from normal test atmospheric conditions, electrical and mechanical performance tests that must be performed before the conditioning test; d.
If necessary, electrical and mechanical performance tests during the conditioning test and the time of the tests, e.
Electrical and mechanical performance tests after the conditioning test, the parameters to be tested first, and the time to complete the tests of these parameters different from this standard.
Additional remarks:
This standard was proposed by the National Technical Committee for Standardization of Environmental Conditions and Environmental Testing for Electrical and Electronic Products. This standard was drafted by the Working Group on Temperature/Humidity Combined Cycle Test Method. The main drafter of this standard was Nie Guocai.The last 2 hours of the 5-hour period are tested at high humidity. It should be understood that many tests conducted under high humidity conditions cannot be directly compared with the results of the initial test or the test results after the test sample is removed from the test chamber. The relevant standards should specify special precautions that must be followed when conducting tests under high humidity conditions, including, when necessary, the method used to remove surface water droplets from the test sample. After the test is completed, the test sample should be removed from the test chamber. 4.4.2 After the test is completed immediately after the test sample is removed from the test chamber, the test sample should be removed from the chamber and maintained under normal test atmospheric conditions. If the initial test is not conducted under normal test atmospheric conditions, this test should be conducted under the same environmental conditions as the initial test.
Within 1 to 2 hours after the test sample is removed from the test chamber, electrical and mechanical properties tests should be conducted. If there is any objection to the results of the initial test during this period, it can be repeated once later in this period, and the results of the later test will be used as the basis for determining failure.
4.4.3 Test after recovery
After the last cycle is over, the test sample should be taken out of the box and kept under normal test atmospheric conditions for 24 hours. If the initial test is not carried out under normal test atmospheric conditions, this test and the initial test should be carried out under the same environmental conditions.
The test can be carried out within 24 hours. If there is any objection to the test result, the test can be carried out at the end of 24 hours, and the measured result can be used as the basis for determining failure.
Details to be specified when adopting this standard
GB 2423.34--86
The state of the test sample during the conditioning test (such as electrical, mechanical load or polarization voltage), pretreatment procedures different from the "dry standard conditions"; b.
Initial test conditions different from normal test atmospheric conditions, electrical and mechanical performance tests that must be performed before the conditioning test; d.
If necessary, electrical and mechanical performance tests during the conditioning test and the time of the tests, e.
Electrical and mechanical performance tests after the conditioning test, the parameters to be tested first, and the time to complete the tests of these parameters different from this standard.
Additional remarks:
This standard was proposed by the National Technical Committee for Standardization of Environmental Conditions and Environmental Testing for Electrical and Electronic Products. This standard was drafted by the Working Group on Temperature/Humidity Combined Cycle Test Method. The main drafter of this standard was Nie Guocai.
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