GB/T 4950-2021 Sacrificial anode of zinc alloy
1 Scope
This document specifies the classification, model and specification, requirements, test methods, inspection rules, as well as marking, packaging, transportation and storage of sacrificial anode of zinc alloy (hereinafter referred to as zinc anodes).
This document is applicable to the design, manufacture, inspection, storage, etc. of zinc anodes for cathodic protection of steel structures in media with resistivity less than 15Ω·m (including seawater, sea mud, soil, etc.), including zinc anodes for cathodic protection of steel structures in ships, port engineering facilities, marine engineering, buried metal pipelines, storage tanks, seawater cooling water systems, etc.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions 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 470-2008 Zinc ingots
GB/T 700 Carbon structural steels
GB/T 1196-2017 Unalloyed aluminium ingots for remelting
GB/T 1499.2 Steel for the reinforcement of concrete - Part 2: Hot rolled ribbed bars
GB/T 6682 Water for analytical laboratory use - Specification and test methods
GB/T 8170 Rules of rounding off for numerical values & expression and judgment of limiting values
GB/T 8923.1-2011 Preparation of steel substrates before application of paints and related products - Visual assessment of surface cleanliness - Part 1: Rust grades and preparation grades of uncoated steel substrates and of steel substrates after overall removal of previous coatings
GB/T 17848 Test methods for electrochemical properties of sacrificial anodes
CB/T 3764 Thickness series and quality requirements for metal plating and chemical coatings
YS/T 72-2014 Cadmium ingot
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
practical current capacity
actual measured amount of electricity generated by the sacrificial anode consumed per unit mass
3.2
current efficiency
ratio of the practical current capacity to the theoretical current capacity of the sacrificial anode
4 Symbols
For the purposes of this document, the symbols given in Table 1 apply.
Table 1 Symbols and designations
5 Classification, model and specification
5.1 Classification
5.1.1 Zinc anodes can be classified by chemical composition into zinc-aluminum-cadmium anodes (Type I and Type II, containing cadmium, and permission from the purchaser shall be obtained before use) and pure zinc anodes (Type III). Among them, the applicable ambient temperature of Type I and Type II zinc anodes shall not exceed 50℃.
5.1.2 Zinc anodes can be classified by their applications into zinc anodes for ship hulls, for liquid cabins, for port engineering and marine engineering facilities, for seawater cooling water systems, for storage tanks, and for buried pipelines.
5.1.3 Zinc anodes can be classified by structural type into single-iron foot welded zinc anodes, double-iron foot welded zinc anodes, bolt-connected zinc anodes, disc-shaped zinc anodes and strip-shaped zinc anodes.
5.2 Model representation
The model representation method of zinc anodes is as follows.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Symbols
5 Classification, model and specification
6 Requirements
7 Test methods
8 Inspection rules
9 Marking, packaging, transportation and storage
Annex A (Nominative) Chemical analysis methods for sacrificial anode of zinc alloy
Annex B (Normative) Determination method of contact resistance
GB/T 4950-2021 Sacrificial anode of zinc alloy
1 Scope
This document specifies the classification, model and specification, requirements, test methods, inspection rules, as well as marking, packaging, transportation and storage of sacrificial anode of zinc alloy (hereinafter referred to as zinc anodes).
This document is applicable to the design, manufacture, inspection, storage, etc. of zinc anodes for cathodic protection of steel structures in media with resistivity less than 15Ω·m (including seawater, sea mud, soil, etc.), including zinc anodes for cathodic protection of steel structures in ships, port engineering facilities, marine engineering, buried metal pipelines, storage tanks, seawater cooling water systems, etc.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions 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 470-2008 Zinc ingots
GB/T 700 Carbon structural steels
GB/T 1196-2017 Unalloyed aluminium ingots for remelting
GB/T 1499.2 Steel for the reinforcement of concrete - Part 2: Hot rolled ribbed bars
GB/T 6682 Water for analytical laboratory use - Specification and test methods
GB/T 8170 Rules of rounding off for numerical values & expression and judgment of limiting values
GB/T 8923.1-2011 Preparation of steel substrates before application of paints and related products - Visual assessment of surface cleanliness - Part 1: Rust grades and preparation grades of uncoated steel substrates and of steel substrates after overall removal of previous coatings
GB/T 17848 Test methods for electrochemical properties of sacrificial anodes
CB/T 3764 Thickness series and quality requirements for metal plating and chemical coatings
YS/T 72-2014 Cadmium ingot
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
practical current capacity
actual measured amount of electricity generated by the sacrificial anode consumed per unit mass
3.2
current efficiency
ratio of the practical current capacity to the theoretical current capacity of the sacrificial anode
4 Symbols
For the purposes of this document, the symbols given in Table 1 apply.
Table 1 Symbols and designations
5 Classification, model and specification
5.1 Classification
5.1.1 Zinc anodes can be classified by chemical composition into zinc-aluminum-cadmium anodes (Type I and Type II, containing cadmium, and permission from the purchaser shall be obtained before use) and pure zinc anodes (Type III). Among them, the applicable ambient temperature of Type I and Type II zinc anodes shall not exceed 50℃.
5.1.2 Zinc anodes can be classified by their applications into zinc anodes for ship hulls, for liquid cabins, for port engineering and marine engineering facilities, for seawater cooling water systems, for storage tanks, and for buried pipelines.
5.1.3 Zinc anodes can be classified by structural type into single-iron foot welded zinc anodes, double-iron foot welded zinc anodes, bolt-connected zinc anodes, disc-shaped zinc anodes and strip-shaped zinc anodes.
5.2 Model representation
The model representation method of zinc anodes is as follows.
Contents of GB/T 4950-2021
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Symbols
5 Classification, model and specification
6 Requirements
7 Test methods
8 Inspection rules
9 Marking, packaging, transportation and storage
Annex A (Nominative) Chemical analysis methods for sacrificial anode of zinc alloy
Annex B (Normative) Determination method of contact resistance
