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GB/T 12000-2017

Chinese Standard: 'GB/T 12000-2017'
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BASIC DATA
Standard ID GB/T 12000-2017 (GB/T12000-2017)
Description (Translated English) Plastics--Determination of the effects of exposure to damp heat, water spray and salt mist
Sector / Industry National Standard (Recommended)
Classification of Chinese Standard G31
Classification of International Standard 83.080.01
Word Count Estimation 14,196
Date of Issue 2017-12-29
Date of Implementation 2018-07-01
Drafting Organization Guangzhou Research Institute of Synthetic Materials Co., Ltd., Mid-Blue Chenguang Chemical Research and Design Institute Co., Ltd., Guangzhou Special Pressure Equipment Testing Institute, Beijing Tian-gang auxiliaries limited liability company, Beijing Huacu Chenguang Technology Co., Ltd., with the Chengdu Science and Technology Co., Ltd.
Administrative Organization National Technical Committee of Plastics Standardization Technical Committee aging method (SAC/TC 15/SC 5)
Proposing organization China Petroleum and Chemical Industry Federation
Issuing agency(ies) People's Republic of China General Administration of Quality Supervision, Inspection and Quarantine, China National Standardization Administration

GB/T 12000-2017
Plastics--Determination of the effects of exposure to damp heat, water spray and salt mist
ICS 83.080.01
G31
National Standards of People's Republic of China
Replace GB/T 12000-2003
Plastic exposed to damp heat, water spray and
Determination of influence in salt spray
(ISO 4611.2010, IDT)
Released on.2017-12-29
2018-07-01 implementation
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
China National Standardization Administration issued
Content
Foreword I
Introduction II
1 range 1
2 Normative references 1
3 Principle 1
4 General test conditions 1
4.1 Equipment Requirements 1
4.2 Exposure conditions 2
4.3 Specimens (see 5.2, 6.2 and 7.2) 3
5 quality change 4
5.1 General 4
5.2 Sample 4
5.3 State adjustment 5
5.4 Step 5
5.5 Results indicate 5
6 Dimensions and appearance changes 6
6.1 General 6
6.2 Sample 6
6.3 State adjustment 6
6.4 Step 6
6.5 result indicates 6
7 Other physical property changes 7
7.1 General 7
7.2 Sample 7
7.3 State Adjustment 7
7.4 Step 7
7.5 Results indicate 7
8 Test report 8
Appendix A (informative) The moisture absorption balance of plastic specimens in a state-regulated environment 9
Reference 10
Foreword
This standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 12000-2003 "Determination of the effects of plastic exposure to damp heat, water spray and salt spray", and GB/T 12000-
Compared with.2003, the main technical changes are as follows.
--- Revised the referenced documents in the "Regulatory References" chapter (see Chapter 2, Chapter 2 of the.2003 edition);
--- Revised the relevant content of the chapter "Test environment and equipment", the chapter name was changed to "general test conditions" (see Chapter 4,.2003 edition)
Chapter 4);
--- Added a detailed description of the requirements for test equipment (see 4.1);
--- Revised the content of the damp heat test conditions (see 4.2.1, 4.1.1 of the.2003 edition);
--- Revised the content of the salt spray test conditions (see 4.2.3,.2003 version 4.1.3);
--- Modified the "Status Adjustment" related content, changed the status adjustment time to "at least 86h" and removed the requirements of the air pressure condition
(See 4.3.1, 4.4 of the.2003 edition).
This standard uses the translation method equivalent to ISO 4611.2010 "Measurement of the effects of plastic exposure to damp heat, water spray and salt spray".
The documents of our country that have a consistent correspondence with the international documents referenced in this standard are as follows.
---GB/T 1034-2008 Determination of water absorption of plastics (ISO 62.2008, IDT)
This standard was proposed by the China Petroleum and Chemical Industry Federation.
This standard is under the jurisdiction of the Technical Committee on Aging Methods of the National Plastics Standardization Technical Committee (SAC/TC15/SC5).
This standard was drafted. Guangzhou Synthetic Materials Research Institute Co., Ltd., Zhonglan Chenguang Chemical Research and Design Institute Co., Ltd., Guangzhou Special Bearing
Pressure Equipment Testing Institute, Beijing Tianzhu Auxiliary Co., Ltd., Beijing Huasu Chenguang Technology Co., Ltd., Tongdao Technology Chengdu Co., Ltd.
the company.
The main drafters of this standard. Wang Fei, Chen Minjian, Li Maodong, Li Weiyi, Wang Haojiang, Liu Wei, Zhang Shukuan, Chen Hongyuan.
The previous versions of the standards replaced by this standard are.
---GB/T 12000-1989, GB/T 12000-2003.
introduction
0.1 There are many test methods for exposing plastics to different etchants that act simultaneously, such as natural weathering. Other test methods
Used to evaluate the effects of individual etchants separately, such as specific chemicals and radiation tests that are resistant to certain spectral ranges.
For some applications, the best approach may be to evaluate not only the performance of the material in a humidified environment with critical saturated vapor pressure, but also
The performance in the presence of the liquid phase was evaluated.
Under these conditions, not only the absorption of water or the leaching of certain components in the composite can be observed, but also due to hydrolysis
The degradation phenomenon caused by the use and the oozing of the plasticizer.
Sometimes it may be necessary to evaluate the properties of materials in the presence of highly corrosive electrolyte solutions, such as sodium chloride solution (salt mist) is a marine environment
The main etchant present, which is especially important for marine applications. It is well known that sodium chloride solution concentrates on the basic components of plastics.
The compound has no significant erosion effect, and because the osmotic pressure of the salt solution is high, the absorption of the salt solution by the plastic is generally higher than that of the pure water.
Less, but it cannot be inferred that the salt solution does not erode the composite containing fillers, reinforcing agents or pigments.
In addition, for finished or semi-finished products consisting mainly of plastic materials but containing certain metal components, the effect of evaluating salt spray may be
very important. These metal components include embedded modules, thin composite foils, surface coatings made by electroplating or other methods, or by extrusion
A metal core coated with plastic, such as a plastic paste or a fluidized bed powder.
0.2 Methods and equipment for obtaining the above reproducible erosive environment are well known and are already in the international standard for other materials.
It is described in the IEC standard for electronic components. With proper maintenance and adjustment, the equipment and methods described in these standards are the same.
The same applies to plastics.
0.3 This standard is only given to the general equipment in selecting the appropriate equipment, obtaining the above exposure conditions and sample preparation methods, and evaluating performance.
Sexual guidance, specific details are specified in different ISO and IEC publications.
Regarding the representation of the results, this standard is as far as possible in accordance with the current test methods for exposure to chemicals (see ISO 175) and exposure to nature.
Test methods for climate or artificial light sources (see ISO 4582).
0.4 These tests provide data on the effects of the above exposures on materials, but do not directly infer the phase between test results and performance.
Relevance.
Plastic exposed to damp heat, water spray and
Determination of influence in salt spray
1 Scope
1.1 This standard specifies the conditions under which plastics are exposed to damp heat, water spray and salt spray, as well as some important performance changes after a given exposure period.
Evaluation method.
1.2 This standard is generally applicable to all plastic standard samples, products or components.
1.3 This standard specifies the following measurement methods.
---Quality change;
--- Size and appearance changes;
--- Other physical performance changes.
2 Normative references
The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this article.
Pieces. For undated references, the latest edition (including all amendments) applies to this document.
ISO 62 plastic moisture absorption measurement (Plastics-Determination of waterabsorption)
3 Principle
One or several properties of the sample are measured after exposure to a given period of exposure and under specified environmental conditions, and the change in appearance is observed. Such as
If necessary, it can be dried or re-adjusted after exposure to obtain the same atmospheric humidity as the original sample.
Balance the state and then measure the performance.
4 General test conditions
4.1 Equipment requirements
4.1.1 General
For steady-state or cyclic exposure test devices with heat, humidity, water spray or salt spray conditions, they shall not interfere with or contaminate the sample.
Made of corrosion-resistant materials that are exposed to exposed samples. In addition, the device should be capable of programming various exposure test conditions.
Sensors for measuring temperature and relative humidity should be installed in the working area of the test chamber.
The condensation water in the test chamber should be continuously discharged, and it should not be reused without purification.
The condensation water on the wall or top of the test chamber shall not drip on the surface of the specimen.
The conductivity of the water used to maintain the humidity of the test chamber should be no more than 20 μS/cm.
For water spray (see 4.2.2) and salt spray (see 4.2.3), the device shall meet the following additional requirements. The test space volume should not be less than
0.4m3, it has been verified that a small test space is difficult to ensure an even distribution of the spray. For large volumes, it is still necessary to ensure that the entire space is sprayed.
Uniformity. The inside of the test chamber should be designed such that the spray water droplets formed on its upper surface do not drip on the surface of the sample.
For the salt spray test (see 4.2.3), considering the environmental factors, it is recommended to install a treatment device. After the test, the salt spray is treated and then discharged.
Go to the atmosphere and treat the brine and discharge it to the sewer system.
For water spray (see 4.2.2) and salt spray (see 4.2.3), the water or salt spray system shall include a source of compressed air, a water or
A salt solution storage tank and one or more sprayers. The compressed air should be filtered to remove oil and solid impurities before reaching the sprayer.
The spray should be carried out at a pressure exceeding 70 kPa. The water or salt solution level should be maintained automatically. In order to avoid the evaporation of water from the spray droplets,
Compressed air should be passed through an infiltration tower containing distilled or deionized water at a temperature above the test temperature of 10 ° C before entering the sprayer.
Wet treatment.
For salt spray tests (see 4.2.3), the resulting salt spray characteristics depend on the pressure used and the type of spray nozzle. Should be adjusted
The amount of salt spray in the test chamber (obtained by measuring the sedimentation rate of the salt spray in the collector) and the salt concentration in the salt spray are maintained at 4.2.3.
Within the specified range.
Note. The exposure conditions in Appendix E of ISO 9142.2003 are similar to those used in this standard.
4.1.2 Temperature
The temperature of the chamber of the test chamber should be controlled within ±2 °C of the required temperature. The allowable deviation of temperature ± 2 ° C takes into account
What is the system measurement error, temperature drift and changes at different points in the test chamber. However, in order to maintain the relative humidity in the entire test chamber at the desired bias
Within the difference range, it is necessary to keep the temperature difference between any two points in the test chamber at any given time within a smaller range. Exposed samples should be avoided
Free of exposure heat from the chamber temperature control unit.
The box temperature should be measured at least 100 mm from the wall of the tank.
4.2 Exposure conditions
4.2.1 Damp heat
4.2.1.1 General
See the exposure conditions described in the preferred IEC publication, see 4.2.1.2 and 4.2.1.3. However, if the relevant product specifications are specified or related
It is agreed that different temperature and/or humidity conditions can be used.
4.2.1.2 Steady state test
Unless otherwise specified, the temperature and humidity conditions of the test chamber at the beginning of the test shall be consistent with the surrounding laboratory environment. Will
The adjusted sample (see 4.3.1) is placed in the test chamber and the test conditions are as follows.
Temperature. 40 2-1 ° C;
Relative humidity. 93 4-8%.
During the heating process, the average rate of temperature change should not exceed 1 ° C/min, and the temperature monitoring period does not exceed 5 min. During the heating process
There should be no condensation on the surface of the sample.
When the specified temperature is reached, the relative humidity is adjusted to reach a prescribed level within 2 hours.
The exposure period should be in accordance with the relevant provisions of the material or product being tested. When there is no specified exposure period, it should be agreed by the relevant parties. Suggested violence
The dew period is 12h, 16h, 24h, 48h, 96h, 240h.
Note. The conditions specified in this clause are consistent with those specified in IEC 60068-2-78.2001.
4.2.1.3 Cycle test
The test requires the test chamber and the sample to undergo a certain number of 24h cycles, during which the temperature should be maintained at an upper temperature limit and
(25 ± 3) °C. One of the following two temperatures should be selected as the upper temperature value.
a) (40 ± 1) ° C (the number of cycles should be 2, 6, 12, 21 or 56);
b) (55 ± 1) ° C (the number of cycles should be 1, 2 or 6).
The upper limit temperature should be reached within the beginning (3 ± 0.5) h of each 24 h cycle. During the temperature rise, except for the relative humidity within the last 15 minutes
It may be less than 95% but not less than 90%. The relative humidity in other periods should not be lower than 95%. During the heating process, the surface of the sample can be allowed to coagulate.
The phenomenon of dew occurs.
Subsequently, the temperature should be maintained at the selected upper temperature limit and the relative humidity should be maintained at (93 ± 4)%.
After 12h cycle, the temperature should be lowered to low temperature (25±3) °C within 3h~6h. Relative humidity should not be low during cooling
At 80%.
During the remainder of the 24h cycle, the temperature should be maintained at (25 ± 3) ° C and the relative humidity should be no less than 95%.
Note 1. The conditions given in this clause are consistent with those specified in IEC 60068-2-30.2005 (Method 2 is used during the temperature drop of the cycle).
Note 2. For mixed temperature/humidity cycles, accompanied by a sub-zero temperature offset, see IEC 60068-2-38.
4.2.2 Water spray
The main difference between water spray exposure conditions and moist heat/steady state exposure (see 4.2.1.2) is that the liquid phase persists as small water droplets.
Suitable equipment to meet these conditions is essentially the same as the salt spray exposure test (see 4.2.3), see the relevant regulations.
Distilled or deionized water should be used instead of the salt solution, pH 6~7.
The test temperature was (40 ± 2) °C.
4.2.3 Salt spray
Prepare a salt solution by dissolving sodium chloride in distilled water or deionized water at a temperature of (25 ± 2) ° C and a conductivity of not more than 20 μS/cm.
It is (50 ± 5) g/L. The specific gravity of the solution at 25 ° C ranges from 1.029 to 1.036.
Determination by atomic absorption spectrophotometry or other similar sensitivity methods, the content of copper and nickel in sodium chloride should be less than
0.001%. In terms of dry salt, the sodium iodide content in sodium chloride should not exceed 0.1%, and the total impurity content should not exceed 0.5%.
Adjust the pH of the salt solution so that the salt spray collected in the test chamber (see below) has a pH between 6.5 and 7.2 at (25 ± 2) °C.
The pH can be measured by a potentiometric method or a conventional method using a precision pH test paper which can resolve a pH unit of 0.3 or less. necessary
At the time, the pH of the salt solution is adjusted by adding hydrochloric acid, sodium hydroxide or sodium hydrogencarbonate solution prepared by analyzing the pure reagent.
The temperature inside the test chamber is (35 ± 2) °C.
The test chamber should have at least two salt spray collection devices. The horizontal collection area of these devices should be 80 cm2. Should pay attention to the safety of the device
Mounting locations, they are only used to collect salt spray, rather than collecting liquid from the sample or other parts of the exposure chamber. Use this device to ensure
Meet the following requirements.
--- The average collection rate of salt spray measured in at least 16h is 1mL/h ~ 2mL/h;
--- At a temperature of (25 ± 2) ° C, the pH of the collected salt spray is between 6.5 and 7.2 (see above);
--- The concentration of sodium chloride in the collected salt spray is (50 ± 5) g/L.
Note 1. The conditions given in this clause are consistent with those specified in ISO 9227.2006 and IEC 60068-2-11.1981.
Note 2. In this test, the exposure test temperature used is 35 ° C, because ISO 9227 and a large number of current national standards specify this temperature, although
It is not recommended for use in ISO 3205.
The exposure period should be in accordance with the relevant provisions of the material or product being tested. When there is no specified exposure period, it should be agreed by the relevant parties. Suggested violence
The dew periods are 2h, 6h, 24h, 48h, 96h, 168h, 240h, 480h, 720h and 1000h.
4.3 Specimens (see 5.2, 6.2 and 7.2)
4.3.1 State adjustment
Unless otherwise agreed by the relevant parties, the sample before the test shall be at a temperature of (23 ± 2) ° C and a relative humidity of (50 ± 10)%.
Adjust for at least 86h.
For some materials, it is known that it reaches the equilibrium state of temperature and humidity (especially humidity) very quickly or very slowly, according to its specific requirements.
Set a shorter or longer state adjustment time (see Appendix A).
4.3.2 Treatment after exposure
4.3.2.1 General
The exposed sample should.
a) test directly after exposure; or
b) Test after drying or re-regulation after exposure.
When it is necessary to know the state of absorption of moisture after the termination of exposure of the material, step a) should be used. When needed to measure only due to exposure
Changes in material properties should be followed by step b). Re-state adjustment should restore the sample to the atmospheric humidity balance before exposure
State (see 4.3.1).
4.3.2.2 Direct test after exposure
Place the exposed sample (if necessary, rinse with distilled or deionized water and dry) into a closed container (23 ± 2) ° C, usually 4h
Just fine.
4.3.2.3 Test after drying or re-regulation after exposure
After the sample is rinsed and dried, it is dried or readjusted to the atmospheric humidity balance before exposure (see 4.3.1). Refer to Appendix A for details.
The procedures of A.3.1 and A.3.2 are carried out. Unless otherwise specified in the relevant product standard or otherwise agreed, the sample shall be at (50 ±
2) Dry in a °C oven for 24 h and cool to (23 ± 2) °C in a desiccator.
When the sample with a thickness of more than.200 μm is dried for 24 hours, the humidity is difficult to reach equilibrium (see ISO 62). Therefore, it is recommended to use a longer drying time.
between. If a longer drying time is used, it should be agreed by the relevant parties and explained in the test report.
5 quality changes
5.1 General
5.1.1 In such tests, the mass change is at least partly due to the absorption of water, so the sample is susceptible to conditioning and drying or heavy
The impact of new state adjustments.
Therefore, accurate test conditions should be specified in the relevant product description.
Usually the sample should be weighed immediately after exposure, rinsing and drying, or treated as described in 4.3.2.2.
If it is necessary to measure the quality after drying or re-regulation, dry or re-adjust the condition as specified in 4.3.2.3.
Note. This test does not apply to porous materials.
5.1.2 The change in mass is usually proportional to the surface area of the sample and is affected by the thickness.
Note. It is important to emphasize that when comparing the properties of different plastics with this test, the specimens are required to have the same shape and size, surface, internal stress, etc.
The status should be as identical as possible.
5.2 Sample
5.2.1 General
The sample can be produced directly by molding or machining. When machined, the surface should be smooth and free from charring marks caused by improper preparation.
5.2.2 Molding and extrusion of plastics
The sample shall be square with a side length (50 ± 1) mm and a thickness of (3.0 ± 0.2) mm, or it may have the same surface area (for example, 100 mm ×
Rectangular specimen of 25 mm, ie 2500 mm 2 ).
The sample may be cut from a sheet of the same thickness, or may be given by the conditions specified in the material or by the supplier of the material.
The parts are obtained by molding, injection molding or extrusion molding.
The molding material can be directly molded by a mold of a prescribed size.
Note. For the preparation of samples for molding and machining, refer to the following standards ISO 293, ISO 294-1, ISO 294-2, ISO 294-3, ISO 295, ISO 2818.
5.2.3 Sheet
The sample shall be a square of (50 ± 1) mm or a rectangle having the same surface area, which is cut from the test piece.
If the nominal thickness of the test sheet is equal to or less than 25 mm, the thickness of the sample shall be the same as the thickness of the sheet.
If the nominal thickness is greater than 25 mm and is not specified in the relevant specifications, it shall be machined on only one of its surfaces.
The thickness of the sample was machined to 25 mm.
Machined surfaces should not be directly exposed to water spray or salt spray.
If machining is done, it should be explained in detail in the test report.
5.2.4 Semi-finished products and finished products (excluding sheets)
The specimen shall be as similar as possible to the specimen as described in 5.2.2 in shape and size and shall be prepared in accordance with the product description or the relevant agreement.
If machining is necessary, it should be explained in detail in the test report.
5.2.5 Number of samples
The sample should be no less than three.
5.3 State adjustment
See 4.3.1.
5.4 Steps
5.4.1 Weigh the mass of each sample (m1) to the nearest 0.001g.
5.4.2 Expose the specimen to a test environment selected from Chapter 4.
5.4.3 If necessary (eg exposed to salt spray), rinse and dry the sample.
5.4.4 Weigh immediately the mass (m2) of each sample to the nearest 0.001g.
5.4.5 If necessary, dry or re-adjust the sample according to 4.3.2.3, and then weigh the mass of each sample (m3), accurate
To 0.001g.
5.5 Results representation
5.5.1 The mass change per unit area (in g/m2) is calculated as follows.
M2-m1
Or m3-m1
In the formula.
M1---the initial mass of the sample, in grams (g);
M2---the mass of the sample immediately after exposure, in grams (g);
M3---the mass after drying or re-regulation of the sample after exposure, in grams (g);
S --- The initial total surface area of the sample (including the side of the sample) in square meters (m2).
5.5.2 The mass change expressed as a percentage is calculated as follows.
M2-m1
M1
×100 or
M3-m1
M1
×100
A positive change in mass indicates an increase in mass and a negative value indicates a decrease in mass.
5.5.3 Calculate the average value of the test results of the sample.
6 Size and appearance changes
6.1 General
Dimensional changes may be due to moisture absorption, leaching of certain components, or due to relaxation of stress in the mold, or due to
The volume change caused by the cause. It is therefore important to specify clear test conditions in the relevant product description.
For anisotropic materials, such as calendered or extruded sheets, extruded bars, linear in the forming direction (longitudinal) and vertical forming direction (lateral)
Dimensions may vary, so it is necessary to test for changes in both directions.
In order to distinguish the effects of stress relaxation and water action in molding, a set of annealed samples can also be used for testing.
6.2 Sample
Prepare the sample as specified in 5.2. For anisotropic materials, the sides should be parallel to the longitudinal or transverse direction, respectively (see 6.1).
The same sample that can be measured for mass change can be measured immediately after weighing.
6.3 State adjustment
See 4.3.1.
6.4 steps
6.4.1 Use a gage to measure the thickness at each of the four marking points of each specimen to the nearest 0.01 mm and calculate the average (d1).
Measure the length of the sides of the square or rectangle one by one, to the nearest 0.1mm, and calculate the average of the two perpendicular dimensions (long
L1 and width b1). For irregularly shaped specimens, such as those obtained from semi-finished or finished products, the most critical dimensions are measured.
6.4.2 Expose the specimen to a test environment selected from Chapter 4.
6.4.3 If necessary (eg exposed to salt spray), rinse and dry the sample.
6.4.4 Re-measure the sample size (l2, b2 and d2) after exposure in the same manner as before exposure.
If the specimen is severely warped, a linear gauge is used for linear dimension measurement.
6.4.5 Record all appearance changes.
6.4.6 If necessary, dry or re-adjust the sample according to 4.3.2.3, then measure the sample size (l3, b3 and d3).
6.5 result representation
The results can be expressed in one of two ways.
a) The percentage change in size relative to the original size is calculated by.
L2-l1
L1
×100,
B2-b1
B1
×100,
D2-d1
D1
×100 (after exposure)
or
L3-l1
L1
×100,
B3-b1
B1
×100,
D3-d1
D1
×100 (the sample after exposure is dried or reconditioned)
A positive value indicates an increase in size and a negative value indicates a decrease in size.
b) The percentage of the final size relative to the original size, calculated as.
L2
L1
×100,
B2
B1
×100,
D2
D1
×100
or
L3
L1
×100,
B3
B1
×100,
D3
D1
×100
The result is 100% indicating no change in size, less than 100% means size reduction, and more than 100% means size increase.
And describe changes in the appearance of the sample, such as warpage, distortion, delamination or obvious signs of surface degradation, such as.
--- change in color and/or gloss, the presence of silver streaks, cracks;
---bubble;
--- plasticizer oozing, sticky;
---The blooming of solid components;
---Corrosion of metal components (if there are metal components);
Qualitative identification, such as mild, moderate, severe, etc., if possible.
7 Other physical property changes
7.1 General
Any physical property can be measured, usually measuring mechanical, optical and electrical properties. Defining test strips in the relevant product description
The pieces are very important.
7.2 Sample
The size, shape and quantity of the sample shall comply with the relevant national standards for performance testing.
In the case of a destructive test, the number of samples should be doubled.
The sample may be in the form of a sheet from which subsequent samples for specific tests can be cut. Due to the effect of exposure on the cutting edge, prepared prior to exposure
The results obtained from the sample may differ from the results obtained after the sample is taken after exposure, so the test sample should specify the sample system.
Preparation procedures.
7.3 State adjustment
See 4.3.1.
7.4 Steps
7.4.1 Measure each required performance value (P1) with the first set of specimens.
7.4.2 Expose the second set of specimens to a test environment selected from Chapter 4.
7.4.3 Rinse and dry.
7.4.4 Measure each performance value (P2) after exposure.
7.4.5 If necessary, expose the third set of samples. After exposure, flush, dry or re-adjust the sample according to 4.3.2.3.
The sample was wiped dry, and the state was adjusted to the same humidity balance state as the sample at the time of P1 measurement, and then each performance value (P3) was measured.
7.5 Result representation
The results can be expressed in one of two ways.
a) The percentage change in performance is calculated by the following formula.
P2-P1
P1
×100 or
P3-P1
P1
×100
b) The percentage of final performance relative to the initial performance, calculated using the following formula.
P2
P1
×100 or
P3
P1
×100
8 test report
The test report should include the following items.
a) indicate the reference to this national standard;
b) a detailed description of the material or product;
c) type of exposure;
d) treatment of the sample before and after exposure;
e) the measured performance;
f) a detailed description of the preparation of the sample, in particular the machining method;
g) sample type;
h) performance values before and after exposure;
i) corresponding changes calculated according to the relevant formulas in 5.5, 6.5, 7.5, including symbols;
j) give a function of performance versus exposure time, if poss......
Related standard: GB/T 12009.2-2016    GB/T 12009.4-2016
Related PDF sample: GB/T 12008.3-2009    GB/T 12008.3-1989