Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 13912-2002 Metallic coatings - Hot dip galvanized coatings on fabricated iron and steel articles - Specifications and test methods. The following main technical changes have been made with respect to GB/T 13912-2002:
——3.16 “zinc melt” and 3.17” weld seepage” are added in “Terms and definitions”.
——4.2 “Base metal” in the original standard is included in 4.1 "General" of this standard; 4.1 “Information to be supplied by the purchaser” in the original standard is adjusted to Annex A of this standard.
——6.3 “Renovation of uncoated or damaged areas” in the original standard is adjusted to Annex E of this standard and supplemented.
——Clause 7 “Test method” in the original standard is canceled. 7.1 “Appearance test”, 7.3 “Adhesion test” and corresponding provisions in Clause 6 in the original standard are combined in this standard. 7.2 “Thickness measurement” in the original standard is adjusted to Annex D of this standard.
This standard has been redrafted and modified in relation to ISO 1461:2009 Hot dip galvanized coatings on fabricated iron and steel articles - Specifications and test methods.
Compared with ISO 1461:2009, this standard has been modified in structure by adjusting Annexes E and C of ISO 1461:2009 to Annexes C and E of this standard respectively.
The main technical deviations with respect to ISO 1461:2009 and their justifications are as follows:
——the adjustments of technical deviations are made for the normative references in this standard so as to adapt to the technical conditions of China. The adjustments are mainly reflected in Clause 2 "Normative references", which are shown in the following:
● ISO 752 is replaced by GB/T 470 which is modified in relation to the international standard (see 4.2);
● ISO 2859-1 is replaced by GB/T 2828.1 which is identical to the international standard (see 6.2.3);
● ISO 2859-2 is replaced by GB/T 2828.2 which is not identical to the international standard (see 6.2.3);
● ISO 2859-3 is replaced by GB/T 2828.3 which is identical to the international standard (see 6.2.3);
● ISO 2178 is replaced by GB/T 4956 which is identical to the international standard (see 6.2.2);
● ISO 3882 is replaced by GB/T 6463 which is identical to the international standard (see 6.2.2);
● ISO 2064 is replaced by GB/T 12334 which is identical to the international standard (see Clause 3);
● ISO 2808 is replaced by GB/T 13452.2 which is identical to the international standard (see 6.2.2);
● ISO 1460 is replaced by GB/T 13825 which is identical to the international standard (see 6.2.2);
● ISO 10474 is replaced by GB/T 18253 which is identical to the international standard (see Clause 7).
The following editorial changes have been made in this standard:
——standard name is changed as Metallic coatings - Hot dip galvanized coatings on fabricated iron and steel articles - Specifications and test methods;
——the contents of Clause 1 "Scope" are appropriately supplemented and adjusted according to GB/T 1.1-2009;
——Annexes C and E are adjusted according to the sequence mentioned in the text.
This standard was proposed by China Machinery Industry Federation.
This standard is under the jurisdiction of the National Technical Committee on Metallic and Non-metallic Coating of Standardization Administration of China (SAC/TC 57).
The previous editions of this standard are as follows:
——GB/T 13912-1992, GB/T 13912-2002.
Metallic coatings - Hot dip galvanized coatings on fabricated iron and steel articles - Specifications and test methods
1 Scope
This standard specifies the specifications and test methods for hot dip galvanized coatings on fabricated iron and steel articles. After-treatment/over-coating of hot dip galvanized articles is not covered in this standard.
This standard is applicable to hot dip galvanized coatings (containing not more than 2% of other metals) on fabricated iron and steel articles (including certain castings). It is not applicable to the following:
a) sheet, wire and woven or welded mesh products that are continuously hot dip galvanized;
b) tube and pipe that are hot dip galvanized in automatic plants;
c) hot dip galvanized products (e.g. fasteners) for which specific standards exist and which might include additional requirements or requirements which are different from those of this standard.
Note: Individual product standards may incorporate this standard for the coating by quoting its number, or may incorporate it with modifications specific to the product. Different requirements may also be made for galvanized coatings on products intended to meet specific regulatory requirements.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 470 Zinc ingots (GB/T 470-2008, ISO 752:2004, MOD)
GB/T 2828.1 Sampling procedures for inspection by attributes - Part 1: Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection (GB/T 2828.1-2012, ISO 2859-1:1999, IDT)
GB/T 2828.2 Sampling procedures for inspection by attributes - Part 2: Sampling plans indexed by limiting quality (LQ) for isolated lot inspection (GB/T 2828.2-2008, ISO 2859-2:1985, NEQ)
GB/T 2828.3 Sampling procedures for inspection by attributes - Part 3: Skip-lot sampling procedures (GB/T 2828.3-2008, ISO 2859-3:2005, IDT)
GB/T 4956 Non-magnetic coatings on magnetic substrates - Measurement of coating thickness - Magnetic method (GB/T 4956-2003, ISO 2178:1982, IDT)
GB/T 6463 Metallic and other inorganic coatings - Review of methods of measurement of thickness (GB/T 6463-2005, ISO 3882:2003, IDT)
GB/T 12334 Metallic and other inorganic coatings - Definitions and conventions concerning the measurement of thickness (GB/T 12334-2001, idt ISO 2064:1996)
GB/T 13452.2 Paints and varnishes - Determination of film thickness (GB/T 13452.2-2008, ISO 2808:2007, IDT)
GB/T 13825 Metallic coatings - Hot dip galvanized coatings on ferrous materials - Gravimetric determination of the mass per unit area (GB/T 13825-2008, ISO 1460:1992, IDT)
GB/T 18253 Steel and steel products - Types of inspection documents (GB/T 18253-2018, ISO 10474: 2013, IDT)
ISO 3549 Zinc dust pigments for paints - Specifications and test methods
EN 1179 Zinc and zinc alloys - Primary zinc
EN 13283 Zinc and zinc alloys - Secondary zinc
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 12334 and the following apply.
3.1
hot dip galvanizing
formation of a coating of zinc and/or zinc iron alloys on iron and steel articles by dipping prepared steel or cast iron in a zinc melt
3.2
hot dip galvanized coating
coating of zinc and/or zinc iron alloys on iron and steel articles obtained by hot dip galvanizing
Note: The term “hot dip galvanized coating” is subsequently referred to as the “coating”.
3.3
coating mass
total mass of zinc and/or zinc alloys per area of iron and steel product surface, expressed in g/m2
3.4
coating thickness
total thickness of zinc and/or zinc alloys on steel and iron surface, expressed in μm
3.5
significant surface
part of the article covered or to be covered by the hot dip galvanized coating and for which the coating is essential for appearance and/or serviceability
3.6
control sample
hot dip galvanized article or group of articles from an inspection lot that is selected for sampling
3.7
reference area
area within which a specific number of single measurements are made
3.8
local coating thickness
mean value of coating thickness obtained from the specific number of measurements within a reference area for a magnetic test or the single value from a gravimetric test
3.9
mean coating thickness
mean value of the local thickness of the coating measured after sampling a “large” article or a lot of galvanized articles
Note: “Large” article herein refers to the article with significant surface larger than 2m2 (see 6.2).
3.10
local coating mass
value of coating mass for an area obtained from a single gravimetric test
3.11
mean coating mass
mean value of the coating masses determined by using the sample selected in accordance with Clause 5 in a gravimetric test in GB/T 13825 or by conversion of the mean coating thickness
3.12
minimum value of the coating thickness
lowest single measurement in a gravimetric test or lowest mean obtained from the specified number of measurements in a magnetic test within a reference area
3.13
inspection lot
hot dip galvanized articles in single order or single delivery
Note: The term “inspection lot” is subsequently referred to as the “lot”.
3.14
acceptance inspection
inspection of an inspection lot at the hot dip galvanizing works, unless otherwise specified
3.15
uncoated areas
areas on the iron or steel articles that do not react with the zinc melt
3.16
zinc melt
molten mass containing primarily zinc
3.17
weld seepage
emission of previously retained pretreatment solutions from narrow spaces between two closely contacting surfaces that have been subject to intermittent welding or from very small cavities (pinholes) in the welds of a galvanized article
4 General requirements
4.1 General
This standard sets out requirements for the contents of the zinc melt used to apply a galvanized coating to articles (see 4.2). The chemical composition and the surface condition (finish and roughness) of the base metal, the mass of the articles and the galvanizing conditions may affect the appearance, thickness, texture and physical/mechanical properties of the coating. This standard does not define any requirements regarding these points. Guidance on these parameters may be found in GB/T 19355.2[7].
4.2 Hot dip galvanizing bath
The hot dip galvanizing bath shall primarily contain zinc melt. The total of the other elements (as identified in GB/T 470, EN 13283 or EN 1179) in the zinc melt shall not exceed 1.5% by mass.
4.3 Information to be supplied by the purchaser
The information listed in A.1 and A.2 of Annex A shall be supplied by the purchaser.
4.4 Safety
Safety measures shall be provided in the manufacturing of hot dip galvanized articles.
5 Acceptance inspection and sampling
Acceptance inspection shall be undertaken before the products leave the hot dip galvanizing works, unless otherwise specified at the time of ordering by the purchaser. Acceptance inspection involves assessment of the coating appearance and measurement of the coating thickness. Adhesion tests are normally not carried out and are only carried out by agreement.
The control sample for coating thickness test shall be taken randomly from each inspection lot (see 3.13), and the minimum number of articles from each inspection lot that forms the control sample shall be in accordance with Table 1.
Foreword i 1 Scope 2 Normative References 3 Terms and definitions 4 General requirements 4.1 General 4.2 Hot dip galvanizing bath 4.3 Information to be supplied by the purchaser 4.4 Safety 5 Acceptance inspection and sampling 6 Coating requirements 6.1 Appearance 6.2 Thickness 6.3 Renovation 6.4 Adhesion 6.5 Acceptance criteria 7 Certificate of compliance Annex A (Normative) Information to be supplied Annex B (Normative) Safety requirements Annex C (Informative) Corrosion resistance of hot dip galvanized coatings Annex D (Informative) Determination of thickness Annex E (Informative) Renovation of uncoated or damaged areas Bibliography
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 13912-2002 Metallic coatings - Hot dip galvanized coatings on fabricated iron and steel articles - Specifications and test methods. The following main technical changes have been made with respect to GB/T 13912-2002:
——3.16 “zinc melt” and 3.17” weld seepage” are added in “Terms and definitions”.
——4.2 “Base metal” in the original standard is included in 4.1 "General" of this standard; 4.1 “Information to be supplied by the purchaser” in the original standard is adjusted to Annex A of this standard.
——6.3 “Renovation of uncoated or damaged areas” in the original standard is adjusted to Annex E of this standard and supplemented.
——Clause 7 “Test method” in the original standard is canceled. 7.1 “Appearance test”, 7.3 “Adhesion test” and corresponding provisions in Clause 6 in the original standard are combined in this standard. 7.2 “Thickness measurement” in the original standard is adjusted to Annex D of this standard.
This standard has been redrafted and modified in relation to ISO 1461:2009 Hot dip galvanized coatings on fabricated iron and steel articles - Specifications and test methods.
Compared with ISO 1461:2009, this standard has been modified in structure by adjusting Annexes E and C of ISO 1461:2009 to Annexes C and E of this standard respectively.
The main technical deviations with respect to ISO 1461:2009 and their justifications are as follows:
——the adjustments of technical deviations are made for the normative references in this standard so as to adapt to the technical conditions of China. The adjustments are mainly reflected in Clause 2 "Normative references", which are shown in the following:
● ISO 752 is replaced by GB/T 470 which is modified in relation to the international standard (see 4.2);
● ISO 2859-1 is replaced by GB/T 2828.1 which is identical to the international standard (see 6.2.3);
● ISO 2859-2 is replaced by GB/T 2828.2 which is not identical to the international standard (see 6.2.3);
● ISO 2859-3 is replaced by GB/T 2828.3 which is identical to the international standard (see 6.2.3);
● ISO 2178 is replaced by GB/T 4956 which is identical to the international standard (see 6.2.2);
● ISO 3882 is replaced by GB/T 6463 which is identical to the international standard (see 6.2.2);
● ISO 2064 is replaced by GB/T 12334 which is identical to the international standard (see Clause 3);
● ISO 2808 is replaced by GB/T 13452.2 which is identical to the international standard (see 6.2.2);
● ISO 1460 is replaced by GB/T 13825 which is identical to the international standard (see 6.2.2);
● ISO 10474 is replaced by GB/T 18253 which is identical to the international standard (see Clause 7).
The following editorial changes have been made in this standard:
——standard name is changed as Metallic coatings - Hot dip galvanized coatings on fabricated iron and steel articles - Specifications and test methods;
——the contents of Clause 1 "Scope" are appropriately supplemented and adjusted according to GB/T 1.1-2009;
——Annexes C and E are adjusted according to the sequence mentioned in the text.
This standard was proposed by China Machinery Industry Federation.
This standard is under the jurisdiction of the National Technical Committee on Metallic and Non-metallic Coating of Standardization Administration of China (SAC/TC 57).
The previous editions of this standard are as follows:
——GB/T 13912-1992, GB/T 13912-2002.
Metallic coatings - Hot dip galvanized coatings on fabricated iron and steel articles - Specifications and test methods
1 Scope
This standard specifies the specifications and test methods for hot dip galvanized coatings on fabricated iron and steel articles. After-treatment/over-coating of hot dip galvanized articles is not covered in this standard.
This standard is applicable to hot dip galvanized coatings (containing not more than 2% of other metals) on fabricated iron and steel articles (including certain castings). It is not applicable to the following:
a) sheet, wire and woven or welded mesh products that are continuously hot dip galvanized;
b) tube and pipe that are hot dip galvanized in automatic plants;
c) hot dip galvanized products (e.g. fasteners) for which specific standards exist and which might include additional requirements or requirements which are different from those of this standard.
Note: Individual product standards may incorporate this standard for the coating by quoting its number, or may incorporate it with modifications specific to the product. Different requirements may also be made for galvanized coatings on products intended to meet specific regulatory requirements.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 470 Zinc ingots (GB/T 470-2008, ISO 752:2004, MOD)
GB/T 2828.1 Sampling procedures for inspection by attributes - Part 1: Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection (GB/T 2828.1-2012, ISO 2859-1:1999, IDT)
GB/T 2828.2 Sampling procedures for inspection by attributes - Part 2: Sampling plans indexed by limiting quality (LQ) for isolated lot inspection (GB/T 2828.2-2008, ISO 2859-2:1985, NEQ)
GB/T 2828.3 Sampling procedures for inspection by attributes - Part 3: Skip-lot sampling procedures (GB/T 2828.3-2008, ISO 2859-3:2005, IDT)
GB/T 4956 Non-magnetic coatings on magnetic substrates - Measurement of coating thickness - Magnetic method (GB/T 4956-2003, ISO 2178:1982, IDT)
GB/T 6463 Metallic and other inorganic coatings - Review of methods of measurement of thickness (GB/T 6463-2005, ISO 3882:2003, IDT)
GB/T 12334 Metallic and other inorganic coatings - Definitions and conventions concerning the measurement of thickness (GB/T 12334-2001, idt ISO 2064:1996)
GB/T 13452.2 Paints and varnishes - Determination of film thickness (GB/T 13452.2-2008, ISO 2808:2007, IDT)
GB/T 13825 Metallic coatings - Hot dip galvanized coatings on ferrous materials - Gravimetric determination of the mass per unit area (GB/T 13825-2008, ISO 1460:1992, IDT)
GB/T 18253 Steel and steel products - Types of inspection documents (GB/T 18253-2018, ISO 10474: 2013, IDT)
ISO 3549 Zinc dust pigments for paints - Specifications and test methods
EN 1179 Zinc and zinc alloys - Primary zinc
EN 13283 Zinc and zinc alloys - Secondary zinc
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 12334 and the following apply.
3.1
hot dip galvanizing
formation of a coating of zinc and/or zinc iron alloys on iron and steel articles by dipping prepared steel or cast iron in a zinc melt
3.2
hot dip galvanized coating
coating of zinc and/or zinc iron alloys on iron and steel articles obtained by hot dip galvanizing
Note: The term “hot dip galvanized coating” is subsequently referred to as the “coating”.
3.3
coating mass
total mass of zinc and/or zinc alloys per area of iron and steel product surface, expressed in g/m2
3.4
coating thickness
total thickness of zinc and/or zinc alloys on steel and iron surface, expressed in μm
3.5
significant surface
part of the article covered or to be covered by the hot dip galvanized coating and for which the coating is essential for appearance and/or serviceability
3.6
control sample
hot dip galvanized article or group of articles from an inspection lot that is selected for sampling
3.7
reference area
area within which a specific number of single measurements are made
3.8
local coating thickness
mean value of coating thickness obtained from the specific number of measurements within a reference area for a magnetic test or the single value from a gravimetric test
3.9
mean coating thickness
mean value of the local thickness of the coating measured after sampling a “large” article or a lot of galvanized articles
Note: “Large” article herein refers to the article with significant surface larger than 2m2 (see 6.2).
3.10
local coating mass
value of coating mass for an area obtained from a single gravimetric test
3.11
mean coating mass
mean value of the coating masses determined by using the sample selected in accordance with Clause 5 in a gravimetric test in GB/T 13825 or by conversion of the mean coating thickness
3.12
minimum value of the coating thickness
lowest single measurement in a gravimetric test or lowest mean obtained from the specified number of measurements in a magnetic test within a reference area
3.13
inspection lot
hot dip galvanized articles in single order or single delivery
Note: The term “inspection lot” is subsequently referred to as the “lot”.
3.14
acceptance inspection
inspection of an inspection lot at the hot dip galvanizing works, unless otherwise specified
3.15
uncoated areas
areas on the iron or steel articles that do not react with the zinc melt
3.16
zinc melt
molten mass containing primarily zinc
3.17
weld seepage
emission of previously retained pretreatment solutions from narrow spaces between two closely contacting surfaces that have been subject to intermittent welding or from very small cavities (pinholes) in the welds of a galvanized article
4 General requirements
4.1 General
This standard sets out requirements for the contents of the zinc melt used to apply a galvanized coating to articles (see 4.2). The chemical composition and the surface condition (finish and roughness) of the base metal, the mass of the articles and the galvanizing conditions may affect the appearance, thickness, texture and physical/mechanical properties of the coating. This standard does not define any requirements regarding these points. Guidance on these parameters may be found in GB/T 19355.2[7].
4.2 Hot dip galvanizing bath
The hot dip galvanizing bath shall primarily contain zinc melt. The total of the other elements (as identified in GB/T 470, EN 13283 or EN 1179) in the zinc melt shall not exceed 1.5% by mass.
4.3 Information to be supplied by the purchaser
The information listed in A.1 and A.2 of Annex A shall be supplied by the purchaser.
4.4 Safety
Safety measures shall be provided in the manufacturing of hot dip galvanized articles.
5 Acceptance inspection and sampling
Acceptance inspection shall be undertaken before the products leave the hot dip galvanizing works, unless otherwise specified at the time of ordering by the purchaser. Acceptance inspection involves assessment of the coating appearance and measurement of the coating thickness. Adhesion tests are normally not carried out and are only carried out by agreement.
The control sample for coating thickness test shall be taken randomly from each inspection lot (see 3.13), and the minimum number of articles from each inspection lot that forms the control sample shall be in accordance with Table 1.
Contents of GB/T 13912-2020
Foreword i
1 Scope
2 Normative References
3 Terms and definitions
4 General requirements
4.1 General
4.2 Hot dip galvanizing bath
4.3 Information to be supplied by the purchaser
4.4 Safety
5 Acceptance inspection and sampling
6 Coating requirements
6.1 Appearance
6.2 Thickness
6.3 Renovation
6.4 Adhesion
6.5 Acceptance criteria
7 Certificate of compliance
Annex A (Normative) Information to be supplied
Annex B (Normative) Safety requirements
Annex C (Informative) Corrosion resistance of hot dip galvanized coatings
Annex D (Informative) Determination of thickness
Annex E (Informative) Renovation of uncoated or damaged areas
Bibliography
