GB/T 4950-2021Sacrificial anode of zinc alloy (English PDF)

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for Standardization Work Part 1: Structure and Drafting Rules of Standardization Documents" Drafting.

This document replaces GB/T 4950-2002 "Zinc-aluminum-cadmium alloy sacrificial anode" and GB/T 4951-2007 "Zinc-aluminum-cadmium alloy sacrificial anode" Polar Chemical Analysis Method. This document is based on GB/T 4950-2002, which integrates the content of GB/T 4951-2007, and Compared with GB/T 4950-2002, in addition to structural adjustments and editorial changes, the main technical changes are as follows.

a) Added a chapter "Symbols" (see Chapter 4);

b) The classification method of zinc anodes is changed (see 5.1, 4.1 of GB/T 4950-2002);

c) The model representation method of zinc anode is changed (see 5.2, 4.2 of GB/T 4950-2002);

d) The structural type and parameters of the bolted zinc anode for the tank have been added (see Table 7 and Figure 6);

e) Added the classification, specifications and parameters of strip zinc anodes for storage tanks and buried pipelines (see 5.3.5 and 5.3.6);

f) The chemical composition and electrochemical performance of two zinc anodes have been added (see 6.2 and 6.3);

g) The number and requirements of samples for type inspection of zinc anodes are changed (see 8.2.3, 7.2.3 and 7.2.4 of GB/T 4950-2002);

h) The chemical analysis method of zinc alloy sacrificial anode has been added (see Appendix A);

i) The method of measuring the contact resistance between the sacrificial anode body and the iron foot has been changed (see Appendix B.2, Appendix A.1 of GB/T 4950-2002).

1 Scope

This document stipulates the classification, model and specifications, requirements, test methods, inspection rules of zinc alloy sacrificial anodes (hereinafter referred to as zinc anodes) And marking, packaging, transportation and storage.

This document applies to zinc used for cathodic protection of steel structures in media with a resistivity of less than 15 ohm·m (including seawater, sea mud, soil, etc.) Design, manufacture, inspection and storage of anodes, including ships, port engineering facilities, marine engineering, buried metal pipelines, storage tanks, seawater cooling water systems Zinc anodes for cathodic protection of steel structures.

2 Normative references

The contents of the following documents constitute the indispensable clauses of this document through normative references in the text. Among them, dated quotations Only the version corresponding to that date is applicable to this document; for undated reference documents, the latest version (including all amendments) is applicable to this document.

GB/T 470-2008 Zinc Ingot

GB/T 700 carbon structural steel

GB/T 1196-2017 Aluminum ingots for remelting

GB/T 1499.2 Steel for reinforced concrete Part 2: Hot-rolled ribbed steel bars

GB/T 6682 Analytical laboratory water specifications and test methods

GB/T 8170 Numerical rounding rules and the expression and determination of limit values

GB/T 8923.1-2011 Visual assessment of surface cleanliness of steel surface treatment before coating-Part 1: Uncoated The corrosion level and treatment level of the steel surface and the steel surface after the original coating has been completely removed

GB/T 17848 Electrochemical performance test method of sacrificial anode

CB/T 3764 Metal coating and chemical coating thickness series and quality requirements

YS/T 72-2014 Cadmium Ingot

3 Terms and definitions

The following terms and definitions apply to this document.

4 Symbols

The symbols listed in Table 1 apply to this document.