Metallic and other non-organic coatings-General rules for corrosion tests applicable for storage conditions
Some standard content:
National Standard of the People's Republic of China
Metallic and other inorganic coatings
General rules for corrosion tests applicablefor storage conditions
GB 11377-89
This standard is equivalent to International Standard (International Standard) 4543-1981 "Metallic and other inorganic coatings-General rules for corrosion tests applicablefor storage conditions".
1 Subject content and scope of application
This standard specifies the corrosion test methods for metals and other inorganic coatings in storage rooms with or without controlled climatic parameters. This standard is applicable to metal coatings, conversion coatings and other engine coverings and their packaging! Sealed specimens, 2 Test purpose
Carry out corrosion tests under storage conditions, the purpose of which is to: evaluate the corrosion resistance of different protective coatings under specific storage conditions R
compare the corrosion resistance of two or more protective coatings: b.
determine the type and maximum depth of the protective coating, as well as the type of protective coating, d.
explore the correlation between the test results under given laboratory test conditions and storage conditions; determine the effective protection period of the protective coating. e
3 Specimens
3.1 Types
The following types of specimens can be used:
Specimens specially prepared with (coated) the test coating or: .
b.: Product components with a protective coating. If product parts are used for testing, the selected components should be representative and reflect their corrosion behavior under actual storage conditions to the greatest extent possible.
Test specimens and product parts with or without protective packaging, and with or without temporary protective layers. The date of the test is determined. 3.2 Shape and size
In order to minimize the error caused by edge effects and subject them to representative corrosion, the surface area of the test specimen should be as large as possible, and in any case not less than 5000mm (50mm×100mm). When the area of the parts used in the test is less than 5000mm\, the same type of parts can be combined as a test specimen to make the total area reach the required minimum surface, but the results obtained may differ from the results of specially prepared specimens with a specified minimum area. 3.3 Quantity
In any batch test, the number of specimens should be determined according to the type of specimen, the number required to evaluate specific physical properties, and the number of specimens that need to be taken out periodically during the test. For a certain day's assessment, the number of samples of one kind shall not be less than 3. 3.4 Marking
Each sample shall be marked to avoid confusion during the storage test. The marking shall be as simple as possible and preferably correspond to the requirements of Chapter 6. The marking shall be clear and recognizable throughout the test. If it is blurred, it shall be re-marked immediately. The marking shall not be marked on the surface that will affect the appearance inspection and its functional role. 3.4.1 The sample can be marked by one of the following methods. a. Punch the mark hole before plating (coating) (the best method); b. Punch the number with steel grade: the number is best marked on the front of the sample; hang a number plate made of corrosion-resistant material on the sample. Use soft non-metallic wire (such as nylon wire) when hanging, and the plate does not touch the sample; the hole for hanging the plate should be punched on the bottom of the sample; d. Paint the sample with a suitable weather-resistant paint. 3.4.2 The marking of the sample can be represented by numbers and letters to indicate the following: type of coating; type of packaging or sealing; if temporary protection is used, the type of temporary protective layer; d. storage location and conditions. 3.5 Standard samples Usually, standard samples of metals (such as zinc, copper or low-alloy steel) are placed next to the coating samples under test to evaluate the corrosion conditions during the test. The corrosion data of the standard samples in the storage room are known, and the standard samples should be stored under the conditions specified in Article 3.6. 3.6 Preservation of samples
Before the test, the samples should be kept in a constant temperature and humidity clean room with a relative humidity not exceeding 50%, or the samples should be sealed in a desiccator or sealed in an evacuated plastic bag containing a desiccant.
4 Storage test conditions
4.1 Corrosive environment
The selected test chamber conditions should be the same or similar to the actual conditions of use or storage of the covering layer and parts. The factors affecting the corrosion of various materials under test are different, and these factors can be any one or more of the following. a.
Atmospheric humidity and its fluctuations;
Atmospheric temperature and fluctuations;
Contaminants in the air, including chemical and physical pollutants;
The temperature of the sample and its fluctuation value;
The surface cleaning quality of the sample;
Biological factors;
Corrosivity of materials in contact with the surface of the sample; h.
The type, quality and impermeability of the packaging or storage. 4.2 Storage room
4.2.1 Requirements for storage room
The storage room should have a roof and be covered by surrounding objects (such as walls or blinds). The floor of the storage room should be dry and clean. If necessary, a moisture-proof floor should be laid, or moisture-proof facilities should be used and dust-absorbing materials should be coated or dust-absorbing equipment should be installed. 4.2.2 Shelves for exposure
Shelves for exposure include sample racks for placing packaged samples (hereinafter referred to as sample racks) and frames for placing unpackaged samples (hereinafter referred to as frames). The structure of the sample rack and the frame is not specifically specified, but should meet the following requirements: GD11377--89
. The materials used must be corrosion-resistant and have no corrosive effect on the samples; b. If the shelf is made of wood, the maximum moisture content of the wood shall not exceed 15%, and it shall not emit corrosive organic compound gas. When designing, it is necessary to consider the effect of wood preservatives on metal and the temporary protective layer on the metal surface as much as possible. C
The frame should keep the sample from moving or swaying: d. Unless otherwise specified, the sample placed on the rack should be at least 0.5m away from the ground, the roof, and the surrounding walls. 4-3 Measuring instruments
Instruments for measuring environmental conditions:
Automatic recording temperature and humidity meter, dry-bulb thermometer, used to measure temperature, absolute humidity and relative humiditya
Instruments for measuring and recording sulfur dioxide radicals, atmospheric dust and nitrogen ions. The placement and operation of the instrument should be carried out in accordance with its use and maintenance instructions. If it is a packaged sample, the humidity inside and outside the package should be measured. 5 Test procedure
5.1 Cleaning of samples before testing
Before the test, the sample should be thoroughly cleaned to remove any contaminants that may affect the performance of the tested cover. The cleaning method used depends on the surface of the specimen and the nature of the contaminants. Any abrasive or drop agent that may damage the surface of the specimen or form a protective film should not be used. 5.2 Sample Cover
Place the samples according to the following rules:
5.2.1 Packaged samples should be placed on the sample channel, and unpackaged samples should be fixed on the frame. 5.2.2 There should be no direct contact between each sample and between the sample and any material that can affect the corrosion of the sample. For this reason, the sample should be fixed on the cradle, and the tools, clamps or clips used to fix the sample should be made of non-metallic materials that are resistant to air corrosion and will not affect the corrosion of the sample. The contact area between the sample and the clamp should be as small as possible. 5.2.3 The sample should be easy to install and remove, and the sample should be easy to inspect. 5.2.4 The sample should be firmly fixed to prevent it from falling off, contamination or damage. 5.2.5 The conditions of each sample should be uniform, so that it can be evenly exposed to air from all directions and avoid the influence of local heat sources, vents and exhaust fans.
5.2.6 It is best to place samples of the same type together and place them in the order of their removal. 5.2.7 After the specimens are placed, a specimen location diagram should be drawn to mark the location of special specimens. 5.2.8 If the test is carried out in different storage rooms, the conditions during the exposure should be as similar as possible so that the results are comparable. To this end, special attention should be paid to the placement of specimens and the size and structural design of the racks and frames used for exposure. 5.2.9 If the test results of coverings and components tested at different times or locations are to be compared, standard specimens are required to compare the corrosion severity of each environment. The placement of standard specimens should be similar to that of the test specimens. 5.3 Duration of test
5.3.1 The total test period is determined based on the purpose of the test and the type of specimen. In principle, the test is carried out continuously until the initial corrosion defects appear in the base metal.
5.3.2 If the samples need to be taken out periodically, the sampling interval depends on the sample type, number and test purpose. 5.3.3 The number of periodic tests shall be determined by the time-dependent corrosion resistance of the test samples. The recommended test cycles are 1 week, 2 weeks, 2, 3, 6 months, 1, 1.5.2, 3.4 and 5 years.
5.4 Evaluation of test results
If conditions permit, the corrosion degree of the samples can be directly evaluated in the storage room where the samples are exposed. If they need to be moved to other places for evaluation, damage, water marks and fingerprints of the samples during the transfer process should be avoided. It is necessary to avoid transferring the samples from a cold environment to a hot and humid environment quickly, and to prevent the samples from undergoing corrosion changes during the transfer process. The evaluation method of the test results shall be determined by the test purpose and plan. Unless otherwise specified, the evaluation of the test results of the metal coating shall be carried out according to the methods specified in the relevant standards.
GB11377—89
Unless otherwise specified, the changes in the corrosion of the specimens shall be evaluated regularly during the entire exposure period according to the test cycle recommended in 5.3 and 3. After the exposure test, the results shall be evaluated within one month. During this period, the specimens shall be stored in accordance with the provisions of 6. 5.5 Record of Corrosion Factors
Before the test, a general evaluation shall be made on the types and extent of corrosion factors in the storage room. During the test, external corrosion factors shall be monitored and recorded as listed in Appendix A (Supplement).
5.6 Record of test results
The observation and evaluation results of the corrosion changes of each sample should be recorded in detail on a card of appropriate design. The record should include the following items:
Sample number or mark;
Exposure test date;
Surface appearance of the sample before the test;
Date of each inspection and evaluation;
Each evaluation should describe the surface appearance changes of each sample in detail, and the weight increase or decrease or other physical properties should be measured regularly. When possible, photos of the samples before, during and after the test should be taken: Use the samples, photos or standard drawings that have not been exposed to instantaneous exposure and are preserved in accordance with the provisions of Article 3.6 to evaluate the corrosion level with the naked eye or other methods; f.
. Evaluation of packaging.
6 Test report
The test report should include the following contents:
6.1 Scope of the test
6.2 Description of the porcelain material of the specially prepared sample
The name, brand, composition and metallographic structure of the base material: 8.
Type of coating, covering material and actual purity: cleaning and preparation method of the base surface before coating; covering preparation method (including post-processing method): appearance of the sample and basic properties of the covering, such as porosity, hardness, ductility, etc., and including measurement methods: e.
Packing or sealing materials and packaging methods. 6.3 Information about component products
Main technical information, such as drawings with material and coating specifications, including coating type, especially the actual thickness of the coating,
Data on the basic properties of the coating, such as porosity, hardness, ductility, etc., with test methods and data before exposure, surface preparation and cleaning methods of the substrate before plating (coating); d. Appearance before test;
Encapsulation method.
6. 4 Information about test components
Exposure location,
Placement or fixing method of the sample:
Test start and end time,
d. Records of external corrosion factors during the test. 6.5 Special samples shall list the inspection date and corrosion change evaluation results according to 5.6, including text description and data. Sometimes, special changes during the test, sample photos and packaging information are also required. Air
Measurement Items
Air temperature
Relative humidity and its change
Absolute humidity and its change
SO2 concentration
Tension
Per HSO
Accumulated humidity per H
Physical dust
Biological factors
Additional Notes:
GB 11377
Appendix A
Types and values of separation factors under storage conditions (supplement)
Irng/mms
This standard is issued by the Ministry of Machinery and Electronics Industry of the People's Republic of China. Test type and frequency
Continuous measurement
Once a week
Continuous measurement
Regular inspection
This standard was drafted by the National Technical Committee for Standardization of Metal and Non-metallic Coatings. The standard was drafted by the Wuhan Institute of Material Protection. The main drafter of this standard is Xia Chunlan.
Explanation
Daily, monthly and annual average values
Maximum and minimum values
Maximum and minimum values
Additional and annual average
Daily and annual total numbers
Chemical composition and total quantity within a month
With or without6. List the inspection date, corrosion change evaluation results, including text description and data, and sometimes special changes during the test, sample photos and packaging information. Air
Measurement Items
Air temperature
Relative humidity and its change
Absolute humidity and its change
SO2 concentration
Tensile strength
Per HSO
Per HAccumulated humidity
Body dust
Biological factors
Additional Notes:
GB 11377
Appendix A
Type and value of separation factors under storage conditions (supplement)
Irng/mms
This standard is issued by the Ministry of Machinery and Electronics Industry of the People's Republic of China. Test type and frequencybzxZ.net
Continuous measurement
Once a week
Continuous measurement
Regular inspection
This standard was drafted by the National Technical Committee for Standardization of Metal and Non-metallic Coatings. The standard was drafted by the Wuhan Institute of Material Protection. The main drafter of this standard is Xia Chunlan.
Explanation
Daily, monthly and annual average values
Maximum and minimum values
Maximum and minimum values
Additional and annual average
Daily and annual total numbers
Chemical composition and total quantity within a month
With or without6. List the inspection date, corrosion change evaluation results, including text description and data, and sometimes special changes during the test, sample photos and packaging information. Air
Measurement Items
Air temperature
Relative humidity and its change
Absolute humidity and its change
SO2 concentration
Tensile strength
Per HSO
Per HAccumulated humidity
Body dust
Biological factors
Additional Notes:
GB 11377
Appendix A
Type and value of separation factors under storage conditions (supplement)
Irng/mms
This standard is issued by the Ministry of Machinery and Electronics Industry of the People's Republic of China. Test type and frequency
Continuous measurement
Once a week
Continuous measurement
Regular inspection
This standard was drafted by the National Technical Committee for Standardization of Metal and Non-metallic Coatings. The standard was drafted by the Wuhan Institute of Material Protection. The main drafter of this standard is Xia Chunlan.
Explanation
Daily, monthly and annual average values
Maximum and minimum values
Maximum and minimum values
Additional and annual average
Daily and annual total numbers
Chemical composition and total quantity within a month
With or without
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