GB/T 1839-2008 English PDF (GBT1839-2008)
GB/T 1839-2008 English PDF (GBT1839-2008)
GB/T 1839-2008: Test method for gravimetric determination of the mass per unit area of galvanized coatings on steel products
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
Replacing GB/T 1839-2003 and GB/T 2973-2004
Test Method for Gravimetric Determination of
the Mass per Unit Area of Galvanized Coatings
on Steel Products
(ISO 1460.1992, Metallic Coatings - Hot Dip Galvanized Coatings on
Ferrous Materials - Gravimetric Determination of the Mass per Unit Area, MOD)
ISSUED ON. MARCH 30, 2008
IMPLEMENTED ON. DECEMBER 01, 2008
Jointly issued by. General Administration of Quality Supervision,
Inspection and Quarantine;
Standardization Administration of the People's
Republic of China.
Table of Contents
Forward ... 3
1 Scope ... 5
2 Normative References ... 5
3 Principle ... 5
4 Test Solution ... 6
5 Samples ... 6
6 Test Procedure ... 7
7 Result Calculation ... 7
8 Reproducibility ... 8
9 Test Report ... 8
Appendix A (Informative) Fluorescence X Ray Measurement Method for the
Mass of Zinc Coating of Galvanized Steel Sheets ... 10
Appendix B (Informative) Comparison between Number of Chapters and
Articles of This Standard and those of ISO 1460.1992 ... 14
Appendix C (Informative) Technical Differences and the Reasons between
This Standard and ISO 1460.1992 ... 15
This Standard modifies and adopts the international standard ISO 1460.1992 "Metallic Coatings - Hot Dip Galvanized Coatings on Ferrous Materials - Gravimetric Determination of the Mass per Unit Area".
For the convenience of comparison, the serial number of the chapters and articles of this Standard and the serial number of chapters and articles of ISO 1460.1992 are listed in Appendix 8.
Modification was made when this Standard adopts ISO 1460.1992. These technical differences are marked with vertical single-line at the margin of the involved articles. Technical differences and their reasons are provided in Appendix C for reference. Compared with ISO 1460.1992, the main differences in this Standard are as follows. - Applicable categories of galvanized coatings were added; they are respectively pure galvanizing coating, zinc-iron alloy coating, zinc-iron alloy and albumen coating (such as zinc -5% aluminum alloy coating and 55% aluminum -zinc alloy coating);
- Deionizer water was added as diluent;
- Requirements on sample areas were added;
- Accuracy of sample weighting by balance was specified; if the coating mass of samples is not less than 0.1g, the weighing shall be accurate to 0.001g; - Appendix A "Fluorescence X Ray Measurement Methods for the Mass of Zinc Coating of Galvanized Steel Sheets" was added.
This Standard replaces GB/T 1839-2003 "Test Method for Gravimetric Determination of Mass per Unit Area of Galvanized Coatings Steel Products" and GB/T 2973-2004 "Zinc Coated Steel Wire Test Method for Gravimetric Determination of Zinc Coating". Compared with GB/T 1839-2003 and GB/T 2973-2004, the main changes in this Standard are as follows.
- Applicable categories of galvanized coatings were added; they are respectively pure galvanizing coating, zinc-iron alloy coating, zinc-iron alloy and
aluminum-zinc coating (such as zinc-5% aluminum alloy coating and 55%
aluminum-zinc alloy coating);
- Accuracy of sample weighting by balance was specified; if the coating mass of samples is not less than 0.1g, the weighing shall be accurate to 0.001g; Test Method for Gravimetric Determination of the Mass per
Unit Area of Galvanized Coatings on Steel Products
This Standard specifies principle, test solution, samples, test procedure, result calculation, reproducibility and test methods for gravimetric determination of the mass per unit area of galvanized coatings on steel products.
The galvanized coatings stated in this Standard include pure galvanizing coating, zinc-iron alloy and aluminum-zinc coating (such as zinc -5% aluminum alloy coating and 55% aluminum-zinc alloy coating). This Standard is applicable to steel products such as hot dip galvanizing and electro-galvanizing which are easy for the determination.
Methods in Appendix A also may be adopted for the mass test for the zinc coating of galvanized steel sheets.
2 Normative References
The following standards contain provisions which, through reference in this Standard, constitute the provisions of this Standard. For dated reference, the subsequent amendments (excluding correction) or revisions of these publications do not apply. However, the parties who enter into agreement based on this Standard are encouraged to investigate the possibility of applying the most recent editions of the standards. For undated references, the latest edition of the normative document applies.
GB/T 8170 Rules for Rounding off of Numerical Values
Galvanized coatings on already-known surface area are dissolved in the test solution with inhibition of corrosion; then the sample mass before-and-after the coatings are dissolved is weighed; finally mass of galvanized coatings per unit area is calculated according to the weighing difference and sample area.
6 Test Procedure
6.1 Clean up the oil stain, dust and water trace etc. on sample surface with cleaning fluid (4.1); dry samples fully.
6.2 Weigh samples by balance; the weighing accuracy shall be better than 1% of expected mass of sample coatings. When the mass of sample coatings is not less than 0.1g, the weighing shall be accurate to 0.001g.
6.3 Immerse samples in the test solution (4.2); the usage of the test solution is generally not less than 10mL per square cm of sample surface area.
6.4 At room temperature, immerse samples completely in the solution; samples may be turned, until coatings are completely dissolved; the obvious stopping of hydrogen deposition (boiling bubble) is judged as the termination of dissolution process. Then take out the samples; flush them in the running water; if necessary, brush away the loose attachments on the sample surface by nylon brush; and finally wash them with ethyl alcohol; dry them rapidly; absorbent paper may also be adopted to absorb the moisture; then dry them rapidly with hot air.
6.5 Weigh samples by balance with the same accuracy with that in 6.2.
6.6 After weighing, determine the exposed surface area after the zinc coatings of samples are dissolved; the accuracy shall achieve 1%. Measurement of steel plates, steel strips, sample diameter or side length shall be accurate to 0.1mm at least. Measurement of steel wire diameter shall be carried out once at each of the mutual vertical positions; then take the average, accurate to 0.1mm.
6.7 For the determination of the mass of single-side zinc coating for galvanized sheets, proper means shall be adopted to seal one side. After finishing the measurement, determine the second side.
7 Result Calculation
7.1 Galvanizing amount [mass (g) per square meter] on steel products (excluding steel wire) per unit area shall be calculated according to Formula (1). The calculation result shall be rounded according to those specified in GB/T 8170; the reserved digits shall be consistent with that indicated in the product standard.
?€??€???? mm ... (1)
?? - mass of galvanized coatings per unit area (steel plates and steel strips shall be Appendix A
Fluorescence X Ray Measurement Method for the
Mass of Zinc Coating of Galvanized Steel Sheets
A.1 Scope of application
This measurement method specifies the principle, test instrument, calibration method and measurement procedures for mass measurement of the galvanized coatings on surfaces of steel plates by XRF.
This method is applicable to measure the mass of hot dipping galvanizing coat, zinc-iron alloy coating and aluminum-zinc coating (such as zinc -5% aluminum alloy coating and 55%aluminium-zinc alloy coating) as well as electro-galvanized zinc coating and zinc-nickel alloy coating.
A.2.1 Primary rays that are generated from the ray source (X ray tube or radioactive isotope) are utilized to illuminate the steel plated covered with metal coatings. Under certain conditions, ferric feature fluorescence X rays (secondary rays) are excited in the body of base steel. When the rays penetrate through metal coatings with different thickness, strength decrease with different degrees will occur. Strength of secondary rays is detected. When conditions for the generation of primary rays and detection of secondary rays are fixed, the detected fluorescence X-ray intensity is the function of coating thickness. Finally mass of coatings is obtained from the quantitative relation between strength and coating thickness.
A.2.2 The primary rays illuminate the steel plates with metal coating. Under certain conditions, the characteristic x r...