GB/T 1839-2008 in English

《GB/T 1839-2008钢产品镀锌层质量试验方法》由TC183（全国钢标准化技术委员会）归口，TC183SC6（全国钢标准化技术委员会钢板钢带分会）执行，主管部门为中国钢铁工业协会。
本标准代替ＧＢ／Ｔ１８３９―２００３《钢铁产品镀锌层质量试验方法》和ＧＢ／Ｔ２９７３―２００４《镀锌钢丝锌层重量试验方法》。本标准规定了钢产品单位面积上镀锌层质量试验方法的原理、试验溶液、试样、试验步骤、结果计算、再现性及试验报告。本标准适用于面积易于测定的热镀锌和电镀锌等钢产品。 本标准与ＧＢ／Ｔ１８３９―２００３和ＧＢ／Ｔ２９７３―２００４相比，主要变化如下：
―――增加了适用的镀锌层类别：纯锌镀层、锌铁合金镀层、锌铁合金和锌铝合金镀层（例如：锌-５％铝合金镀层、５５％铝-锌合金镀层）；
―――对于用天平称量试样的准确度作了规定，当试样的镀层质量不小于０．１ｇ 时称量应准确到０．００１ｇ
―――增加了附录Ａ《镀锌钢板锌层质量的荧光Ｘ 射线测量法》。

1 Scope

This Standard specifies principle, test solution, samples, test procedure, result calculation, reproducibility and of test methods for gravimetric determination of the mass per unit area of galvanized coatings on steel products.
The stated galvanized coatings in this Standard includes pure galvanizing coating as well as zinc-iron alloy and allumen 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 provisions of this Standard. For dated reference, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, the parties to agreements 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

3 Principle

Galvanized coatings on the already known surface area are dissolved in the test solution with inhibition of corrosion and then sample mass before and after coatings are dissolved is weighed; finally mass of galvanized coatings per unit area is calculated according to the weighing difference and sample area.

4 Test Solution

4.1 Cleaning fluid
Chemically pure absolute alcohol.
4.2 Test solution
4.2.1 3.5g chemically pure hexamethylene tetramine (C6H12N4) is dissolved in 500mL concentrated hydrochloric acid (ρ=1.19g/mL) and then distilled water or deionizer water is adopted to dilute it to 1000mL.
4.2.2 If the test solution may be able to dissolve galvanized coatings, it may be used repeatedly.

5 Samples

5.1 Sampling position and quantity shall be implemented according to the requirements of product standard and mutual agreement.
5.2 Test surface shall be selected according to the thickness of coatings to ensure samples to meet requirements on weighing accuracy.
5.3 Attention shall be paid to avoid surface damage in cutting off samples and samples with partial visible damage shall not be used.
5.4 Samples of steel plates and steel strips may be round or square and single-side area for arbitration test shall be 3000mm2-5000mm2.
5.5 Length of wire samples shall be cut off according to those specified in Table 1.

1 Scope
2 Normative References
3 Principle
4 Test Solution
5 Samples
6 Test Procedure
7 Result Calculation
8 Reproducibility
9 Test Report
Appendix A (Informative) Fluorescence X Ray Measurement Method for the Mass of Zinc
Coating of Galvanized Steel Sheets
Appendix B (Informative) Comparison between Number of Chapters and Articles of This
Standard and those of IS0 1460:
Appendix C (Informative) Technical Differences and the Reasons between This Standard
and IS0 1460: