JB/T 6073-1992 Laboratory full immersion corrosion test for metal coverings
Some standard content:
Industry Standard
Standard of the Machinery Industry of the People's Republic of China
JB/T607392
Metal Covering
Published on May 5, 1992
Laboratory Full Immersion Corrosion Test
Implementation on July 1, 1993
Published by the Ministry of Machinery and Electronics Industry of the People's Republic of China
Standard of the Machinery Industry of the People's Republic of China
Metal Covering
1 Subject Content and Scope of Application
Laboratory Full Immersion Corrosion Test
JB/T6073-92
This standard specifies the laboratory full immersion corrosion test method for metal coverings in various corrosive liquid media. This standard is applicable to the full immersion corrosion test performance evaluation of metal coverings and chemical conversion films. The results obtained from this test can only be used to evaluate the corrosion resistance of the tested covering in a certain test medium. It cannot be used to refer to the corrosion resistance of this covering in other media.
2 Reference standards
JB/T6074 Preparation, cleaning and evaluation of corrosion samples 3 Test equipment
3.1 Container
3.1.1 The container material should be insensitive to the corrosive medium, such as glass, plastic, ceramic, etc. 3.1.2 When testing under boiling or high temperature conditions, a reflux condenser should be installed. 3.1.3 When testing at a lower temperature, a wide-mouth container with appropriate sealing can be used to ensure the balance of the test solution. 3.2 Heater
According to different temperature requirements, a heat source with a temperature control system such as a bath essence or a heating furnace can be used. 3.3 Sample support system
3.3.1 The sample support system should be able to support the sample in the test solution, and the area in contact with the sample should be as small as possible 3.3.2 The material of the support system should be insensitive to the test solution and the sample, and generally a glass bracket or hook is used. Support systems made of plastic, ceramic and chemical fiber can also be used. However, porous and multi-fiber cotton and linen threads or ropes should not be used. 3.4 Other devices
During the test, if the test solution needs to be stirred or continuously flowed and replenished, corresponding devices must be designed and added according to the actual situation. 4 Test specimens
4.1 Shape and size of the test specimen
4.1.1 The shape and size of the test specimen depend on the purpose of the test, the properties of the material and the container used. The test specimens with a large ratio of surface area to mass and a small ratio of edge area to total area should be used as much as possible. 4.1.2 The total surface area of \u200b\u200beach test specimen should not be less than 1000mm. Two shapes of test specimens are recommended. Specifications are as follows: Plate specimen: l\u00d7b\u00d7h, mm50\u00d725\u00d7(2~3) or 30\u00d715\u00d7(1.5~3)
Net specimen: medium xh, mm
38\u00d7(2~3)
or 30\u00d7(2~3)
The shape and specifications of the specimens tested in the same batch should be the same4.1.3
4.1.4 Take at least 3 parallel specimens for each test. 4.2 Specimen preparation
4.2.1 Specimen type
Approved by the Ministry of Machinery and Electronics Industry on May 5, 1992 and implemented on July 1, 1993
Industry standard
The following types of specimens can be used:
JB/T6073-92
a. Specially prepared specimens with tested covering layers; b. Product parts with covering layers.
If the test is carried out on product parts, the selected parts should be representative. 4.2.2 Sample marking
If necessary, identification marks can be made on the sample by appropriate methods, such as steel stamping, electro-engraving or marking with paint resistant to test solution corrosion. This operation must be very careful to avoid causing obvious local corrosion or stress corrosion cracking. Marks should not be marked on surfaces with functional functions.
If the sample needs to be hung, a hole can be drilled on the sample. The recommended hole diameter is not greater than 5mm. 4.2.31
4.2.4 The parts of the sample that are not coated with the protective layer should be sealed with inert materials that do not affect the test, such as paint or paraffin. 4.2.5 The sample must be fully cleaned before the test. The cleaning method depends on the sample material, surface condition and the nature of the dirt. Generally, it is fully cleaned with water, then cleaned with solvents such as acetone and alcohol, blown dry or baked, and then stored in a desiccator. After it returns to ambient temperature, the area is measured and weighed. 4.2.6 When measuring the size and weighing the cleaned specimen, it is not allowed to touch the mold directly with your hands. You should wear clean working gloves. The measuring tools must be clean of oil.
4.2.7 The calculation of the surface area of \u200b\u200bthe specimen should be accurate to 1mm, and the mass should be accurate to 0.001g. 5 Test conditions
5.1 The test conditions are determined by the purpose of the test. The factors that usually need to be controlled in the test include the solution components and their concentrations, pH value, temperature, volume, and whether there is trace gas.
5.2 In order to ensure the reproducibility of the test results, the test conditions should be controlled in a certain order. 5.3 Test solution
5.3.1 The source and composition of the test solution are determined by the purpose of the test. Generally, there are two types: natural and artificial. a. Natural ones include seawater, industrial wastewater, and media directly taken from the production process. When using this type of solution, its composition needs to be determined, and the minor components cannot be ignored.
b. When preparing the solution manually, use distilled water or deionized water and reagents of analytical grade or above that meet the national or departmental standards. If other lower-grade reagents are used, please indicate in the report. 5.3.2 The concentration of the solution is expressed in mol/L. If other methods are used, please indicate. 5.3.3 The pH value and the amount of dissolved gas in the aqueous solution may affect the corrosion rate and should be measured and controlled when necessary. 5.3.4 The amount of test solution should be proportional to the surface area of \u200b\u200bthe sample and the corrosion rate should be considered. If the corrosion rate is less than 1mm/a, the amount of solution required for each square centimeter of the sample shall not be less than 20mL: if the corrosion rate is greater than 1mm/a, the amount of solution required for each square centimeter of the sample shall not be less than 40mL.
5.3.5 The temperature fluctuation of the test solution should be controlled within \u00b11\u2103. When testing at room temperature, the upper and lower limits of the actual temperature during the test period and the average temperature should be stated in the report.
5.3.6 When testing under solution evaporation conditions, zeolite should be used to avoid bubble impact. 5.3.7 When the viscosity of the test solution is high, a magnetic stirrer can be used for stirring. 5.3.8 If dissolved oxygen needs to be eliminated, inert gas (such as nitrogen) can be used for ventilation. If the test solution is required to be saturated with oxygen, oxygen can be used. When ventilating, avoid direct spraying of the air flow on the sample.
6 Test time
6.1 The test time refers to the time from the time when the sample is free of liquid after the solution reaches the specified temperature to the time when the sample is taken out. 6.2 The test time is calculated accurately to 5/1000. 6.3 The length of the test time depends on the corrosion rate of the test material and whether a passivation film can be formed in the test solution. --Generally, the longer the test time, the more accurate the result, but for materials with severe corrosion, the test time should not be too long. For materials that are prone to forming a passive film, extending the test time will yield more realistic results.
Industry Standard
JB/T6073\u201492
6.4 Test time is as specified in the table below. The most commonly used test cycle is 48 to 168 hours (2 to 7 days). Selection of test time
Estimate or predict 1\
Corrosion rate mm/a
>0.1~1
>0.010.1
\u22640.01
Test time h
1000
Note: 1) When predicting the corrosion rate, the test time is 24h, and the solution volume is always 20mL/cm* Whether to replace the solution
Not replace
Not replace
Replace once every 10d
Replace once every 10dbZxz.net
6.5 When the solution needs to be replaced during the test, the operation should be quick and the sample should not be treated in any way. The total operation time for replacing the solution should not exceed 0.5% of the total test time, and the test time lost at this time can be deducted. 6.6 If you need to understand the effect of test time on the metal corrosion rate and the corrosiveness of the test solution, and determine the best test cycle, you can use a planned intermittent corrosion test method, see Appendix A (reference) 7 Test Procedure
7.1 Take an appropriate amount of solution according to 5.3.5 and put it in a fully washed test container. 7.2 When testing at room temperature, the container can be placed in the fume hood of the test room or other appropriate places. 7.3 When the test temperature is higher than room temperature, place the container on a heat source and heat it up quickly. If necessary, the circulating cooling water of the condenser should be connected first. 7.4 After the solution reaches the test temperature, immerse all the samples with measured surface area and weight in the solution and start timing. If there are bubbles attached to the surface of the sample, shake the sample or solution to remove the bubbles. 7.5 The sample should be placed in the middle of the liquid as far as possible, and keep the same distance from the liquid surface, and it is not allowed to contact the container wall. The distance between the samples in the container is more than 1cm. Only the same type of samples can be placed in the same solution. 7.6 During the boiling test, the solution should be kept in a slightly boiling state. For the test solution with high viscosity, an appropriate amount of boiling aids (such as glass balls, tetrafluoroethylene chips, etc.) can be added.
7.7 During the test, the changes of the sample and the solution should be observed frequently and recorded. 7.8 When the test reaches the predetermined time, take out the sample, wash it with water or an appropriate solvent, and then wipe off the corrosion products with a brush, rubber or other tools. It can also be cleaned by ultrasonic method.
7.9 When the corrosion products are difficult to remove, they can be removed by electrolysis or chemical method according to Articles 3.1 and 3.2 of JB/T6074. 7.10 After cleaning, the sample shall be processed according to Articles 4.2.5~4.2.7. 8 Calculation and evaluation
8.1 After cleaning and weighing, the appearance of the sample should be carefully checked. If there is local corrosion, it should be evaluated according to the relevant test method. 8.2 If it is uniform corrosion, the average corrosion rate of all parallel samples tested is used as the main evaluation of the test results. When the relative deviation between the corrosion rate of a parallel sample and the average value exceeds \u00b110%, a new sample should be taken for repeated testing. If it still does not meet the requirements. The average value of the two tests and the corrosion rate of each sample should be given at the same time. 8.3 The corrosion rate is calculated according to formula (1):
R= 8.76\u00d710*\u00d7(WW.).
W\u2014\u2014the mass of the sample before immersion, g;
Industry standard
Wt\u2014\u2014the mass of the sample after immersion\u00b7g;
S\u2014\u2014the total surface area of \u200b\u200bthe sample, cm\;
T\u2014\u2014the test time, h;
D\u2014\u2014the density of the covering material\u00b7g/cm'Test report
The test report should be Include the following contents:
Information about the sample
JB/T6073-92
Instructions on the name, brand, composition and metallographic structure of the base material; a.
Methods for cleaning and preparing the base surface;
Type and actual thickness of the covering layer;
Methods for preparing the covering layer (including post-processing methods); appearance of the sample and basic conditions of the covering layer, such as porosity, hardness, ductility, etc., and including measurement methods. Composition and concentration of the test fluid, test temperature and test time, phenomena occurring during the test and appearance of the sample after corrosion. Sample evaluation items and methods, such as cleaning methods for corrosion products. Test results, such as corrosion rate.
Signatures of the operator and reviewer.
9.7 Date of report.
Description of other situations.
Industry Standard
Serial Number
Additional Notes:
Corrosivity of Solution
No Change
No Change
No Change,
Decrease
Decrease
Decrease
Increase
JB/T6073\u201492
Comprehensive Situation Evaluation Table
Table A2
Metal Corrosion Rate
No Change
Decrease
Increase
No Change
Decrease
Increase
No Change
Decrease
This standard is proposed and managed by Wuhan Materials Protection Research Institute of the Ministry of Machinery and Electronics Industry. Wuhan Materials Protection Research Institute is responsible for drafting this standard. The main drafters of this standard are Xia Lan and Li Xingying. This standard was drafted by Wuhan Institute of Material Protection. The main drafters of this standard are Xia Chunlan and Li Xinglian.Rb< Re
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