Preparation of steel substrates before application of paints--Tests for the assessment of surface cleanliness--Laboratory determination of chloride on cleaned surfaces
Some standard content:
ICS25.220.10
National Standard of the People's Republic of China
GB/T18570.2--2001
eqvIs08502-2:1992
Preparation of steel substrates before application ofpaints and related productsTests for the assessmentof surface cleanliness-Laboratory determination ofchloride on cleaned surfaces2001-12-13 issued
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
2002-08-01 implementation
GB/T18570.2--2001
This standard is compiled based on ISO8502-2:1992 "Surface preparation of steel before coating - Tests for assessment of surface cleanliness - Part 2: Laboratory determination of nitrides on cleaned surfaces" and is equivalent to this international standard in technical content and writing format. The difference between this standard and ISO8502-2 is that this standard deletes the "Introduction" of ISO8502-2, and Chapter 1 "Scope" is written in the format of GB/T1.1-1993; Chapter 2 "Reference Standards" deletes ISO8501-1:1988 and ISO8501-2:1992 accordingly, adds GB/T3051-19825.12 adds "microburette", adds 5.13 "conical flask", adds 6.2.1, 6.2.2, 6.2.3, 6.2.4 numbers in 6.2, and adds 6.4 "waste liquid treatment" in Chapter 6. This standard is proposed by China Shipbuilding Industry Corporation. This standard is under the jurisdiction of the 11th Institute of China Shipbuilding Industry. Drafting unit of this standard: China Shipbuilding Industry 11th Institute. The main drafter of this standard: Qin Yinhua.
GB/T18570.2 —2001
ISOForeword
ISO (International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The development of international standards is usually carried out by ISO technical committees. Each member body has the right to participate in the committee if it is interested in the subject of a technical committee. Official or unofficial international organizations associated with ISO may also participate in this work. ISO works closely with the International Electrotechnical Commission (IEC) in all aspects of electrotechnical standardization. The draft international standards adopted by the technical committees are sent to the member bodies for voting. At least 75% of the member bodies participating in the voting must vote in favor of the draft standards before they can be published as international standards. International Standard ISO8502-2 was developed by ISO/TC35/SC12\Technical Committee on Paints and Varnishes, Subcommittee on "Surface Preparation of Steel Materials Before Double Coating".
ISO 8502, under the general title "Preparation of steel substrates prior to application of paint - Tests for assessment of surface cleanliness", consists of the following substandards: Part 1: Field test for soluble ferrous corrosion products (technical report) Part 2: Laboratory determination of chloride on cleaned surfaces Part 3: Assessment of dust on steel substrates prior to application of paint (pressure-sensitive tape method) Part 4: Guidelines for assessment of the potential for condensation prior to application of paint Part 5: Determination of chloride on steel substrates prior to double coating - Ion detector method Part 6: Sampling of soluble impurities on surfaces to be coated - Bresle method Part 7: Analysis of soluble impurities on surfaces to be coated - Field analysis of oils and fats Part 8: Analysis of soluble impurities on surfaces to be coated - Field analysis of moisture Users should note that the above parts 5 to 11 are only topics for future work. It is planned to publish all the parts listed above. When published, one or more of the topics may be deleted from the outline of work and the remaining parts may be renumbered. 1 Scope
National Standard of the People's Republic of China
Surface preparation of steel substrates before application of paints
Tests for the assessmentof surface cleanliness-Laboratory determination ofchloride on cleaned surfaces Preparation of steel substrates before application ofpaints and related products-Tests for the assessmentof surface cleanliness-Laboratory determination ofchloride on cleaned surfaces This standard specifies the method for determining water-soluble chloride on the surface of steel. GB/T18570.2—2001
eqvISo8502-2.1992
This standard applies to the determination of nitrides on the surface of steel. This standard also applies to surfaces previously coated with paint. This standard does not apply to steel surfaces treated with chromates or nitrites as corrosion inhibitors during wet blasting. Note 1: Although the determination of oxygen ions is correct, the overall accuracy is affected by the sampling process. The iron oxide present in the rust pit is difficult to extract into the sample. 2 Reference standards
The clauses contained in the following standards constitute the clauses of this standard by being referenced in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T3051-2000 General method for determination of chloride content in inorganic chemical products Mercury titration method GB/T6682-1992 Specifications and test methods for water in analytical laboratories (neq1SO3696:1987) 3 Principle
Rinse the steel surface of a certain area with a known volume of water, then use diphenylcarbazone-bromophenol blue as a mixed indicator and titrate the nitride in the rinse with a standard solution of mercuric nitrate. During the titration, mercury ions react with free chloride ions to form mercuric nitride that is slightly soluble in water. When the nitrogen ions react, the excess mercury ions react with diphenylcarbazone to produce purple, which is the titration end point. Note 2: The methods specified in this standard should be performed by qualified chemical engineers or appropriately trained personnel. If appropriate protective measures are not taken, the methods and substances used in this standard may be harmful to human health. See Note 3 of this standard. 4 Reagents
During the analysis, the reagents should be analytically pure reagents, and the purity of water should be at least Grade 3 water as specified in GB/T6682. 4.1 Nitric acid solution: concentration is about 0.05 mol/L. 4.2 Sodium hydroxide solution: concentration is about 0.025 mol/L. 4.3 Potassium hydroxide standard solution: concentration is 100 mg/L. 4.4 Mercuric nitrate standard solution: concentration is 0.0125 mol/L. Note 3 Mercuric nitrate is toxic and should be avoided from contact with eyes and skin. 4.4.1 Preparation
Approved by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on December 13, 2001, implemented on August 1, 2002
GB/T18570.2—2001Www.bzxZ.net
Dissolve 4.171g of mercuric nitrate hydrate in water, pour into a 1000mL volumetric flask, and add water to the scale. 4.4.2 Calibration
Pipette 20mL of potassium nitride standard solution into a 250mL conical flask, add 5 drops of diphenylcarbazone-bromophenol blue mixed indicator solution, and stir. If bluish purple or red appears, add nitric acid solution drop by drop until the color changes to yellow, and then add 1mL of excess nitric acid solution. If yellow or brown is formed immediately after adding the indicator, add sodium hydroxide solution drop by drop to obtain bluish purple. Then acidify and titrate the yellow acidified solution with mercuric nitrate solution until the entire solution changes to bluish purple. Keep the titration solution and compare it with the titration solution obtained from the blank titration in 6.1. Calculate the concentration of the mercuric nitrate solution. Note 4: 1. mol of mercuric ion is equivalent to 2 mol of chloride ion. 4.5 Diphenylcarbazide-bromophenol blue mixed indicator solution Dissolve 0.5g of diphenylcarbazide crystals and 0.05g of bromophenol blue crystals in 75mL of alcohol (concentration is 95%), and add alcohol to 100mL. Store in a brown bottle.
5 Apparatus and materials
Ruler and white chalk or other appropriate tools to mark the test area. 5.11
Absorbent cotton pad (cotton pad): 1~1.5g. 5.3
Metal scraper or blade.
Plastic gloves.
Beaker: 250mL.
5.6 Small glass rod.
Funnel.
Filter paper: about 120mm in diameter.
Volume sachets: 50mL.
Volume flasks: 50mL, 100mL and 1000mL. 5.10
Pipette: 1mL and 20mL.
5.12Burette: microburette with a graduation value of 0.01 or 0.02, or a digital burette. 5.13
3 Conical flask: 250mL.
6 Procedure
6.1 Blank titration
Follow the steps in 4.4.2 and replace the potassium chloride solution with 20mL of water for blank titration. Keep the titrated solution for comparison of the titration endpoint.
6.2 Rinsing of the surface
6.2.1 The test should be carried out at least twice. During the scrubbing process, clean plastic gloves should be used to ensure that no contaminants are carried over from the rinse solution.
6.2.2 Use a ruler and chalk or other appropriate tools to measure approximately 25000 mm2 (e.g. 250 mm×100 mm) of the surface and mark the test area.
6.2.3 Take two beakers A and B, use a measuring book to take 45 mL of water, and pour it into beaker A. Submerge an absorbent cotton pad in the water and then scrub the entire test area with the cotton pad. Do not allow water to drip from the cotton pad or escape from the test area. Wipe the surface dry with an absorbent cotton pad and squeeze the cleaning solution on the cotton pad into beaker B.
For bare steel, scrape the surface with a metal scraper or blade until at least 50% of the test area shows the original color of the metal. Repeat the scrubbing. If the cotton pad is worn out, use a new cotton pad and continue in the same way until all the water is used up. Keep the used absorbent cotton pad. The scrubbing process should last at least 5 minutes.
6.2.4 Filter the rinse liquid with filter paper and funnel, collect the filtrate with a 50mL volumetric flask, use about 5mL water, beaker B and small glass cup 2
GB/T18570.2-2001
Wash the used absorbent cotton pad and filter paper, squeeze the absorbent cotton pad, collect the rinse liquid into the volumetric flask, and add water to the scale line. 6.3 Titration of rinse liquid
Carefully shake the 50mL volumetric flask, use a pipette to draw 20mL of rinse liquid into a clean conical flask, and determine the chloride content using the method given in 4.4.2.
6.4 Waste liquid treatment
Retain the mercury-containing waste liquid after titration and treat it according to the provisions of Appendix D of GB/T3051-2000. 7 Result expression
Calculate the amount of nitride per unit area according to formula (1). Px(CI) = (Vi -Vo)C × 1.773 × 10′A
Where: pA(CI) is the amount of chloride per unit area, mg/m2; V, is the volume of mercuric nitrate solution used for titration, mL, V. The volume of mercuric nitrate solution used for blank titration, mL, C is the actual concentration of mercuric nitrate solution, mol/LA, and the flushing surface area is mm2.
Each calculation result should be accurate to 10 mg/m2.
(1)
Note 5: The protective performance of each coating system is affected by the watertight oxide spots on the steel surface. Its acceptability is related to the conditions of use, and experienced personnel are required to determine the respective usage limits. 8 Test report
The test report should include the following contents:
a) mark the shape and position of the test surface (such as horizontal, vertical and angle); b) the number of this standard;
c) test results;
d) differences from the test method of this standard;
e) test date.
GB/T18570.2-2001
National Standard of the People's Republic of China
Surface preparation of steel before coating
Test for evaluation of surface cleanliness
Laboratory determination of chloride on cleaned surface GB/T18570.2-2001
Published by China Standards Press
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China Standard Press, printed by Huangdao Printing Factory, distributed by Beijing Xinhua Bookstore, sold by Xinhua Bookstores in various places, size 880×12301/16 printing sheet 1/2 word count 11,000 words, first edition in April 2002, first printing in April 2002, print run 1-1000
Book number: 155066·1-18245, list price 8.00 yuan, website bzcbs.com
All rights reserved. Infringements will be investigated
Report phone number: (010) 685335332-2001
Published by China Standards Press
No. 16, Sanlihebei Street, Fuxingmenwai, Beijing
Postal Code: 100045
Tel: 6852394668517548
Printed by China Standards Press, Huangdao Printing Factory, Xinhua Bookstore, Beijing Distribution Office, Sold by Xinhua Bookstores in various places, Format 880×12301/16 Printing Sheet 1/2 Number of Words 11,000 First Edition April 2002 First Printing April 2002 Print Quantity 1-1000
Book Number: 155066·1-18245 Price RMB 8.00 Website bzcbs.com
Copyright Exclusive. Infringements Will Be Prosecuted
Report Telephone: (010) 685335332-2001
Published by China Standards Press
No. 16, Sanlihebei Street, Fuxingmenwai, Beijing
Postal Code: 100045
Tel: 6852394668517548
Printed by China Standards Press, Huangdao Printing Factory, Xinhua Bookstore, Beijing Distribution Office, Sold by Xinhua Bookstores in various places, Format 880×12301/16 Printing Sheet 1/2 Number of Words 11,000 First Edition April 2002 First Printing April 2002 Print Quantity 1-1000
Book Number: 155066·1-18245 Price RMB 8.00 Website bzcbs.com
Copyright Exclusive. Infringements Will Be Prosecuted
Report Telephone: (010) 68533533
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