ASTM B843-18e1

Standard Specification for Magnesium Alloy Anodes for Cathodic Protection

ABSTRACT
This specification covers the standard requirements for magnesium alloy anodes in the form of cast and extruded shapes for use in cathodic protection. Materials shall adhere to specified chemical composition requirements, the samples for analysis of which shall be taken either from the molten metal when the cast anode or extrusion ingot is poured, or from the finished anode. Anodes shall have a clean surface and be commercially free of dirt, slag, or other foreign material.
SIGNIFICANCE AND USE
3.1 This specification is prescriptive and not performance in nature.
SCOPE
1.1 This specification covers magnesium alloy anodes in the form of cast and extruded shapes.  
1.2 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Apr-2018
• ICS: 77.060 - Corrosion of metals
• Technical Committee: B07 - Light Metals and Alloys
• Drafting Committee: B07.04 - Magnesium Alloy Cast and Wrought Products

Relations

• Replaces: ASTM B843-18 - Standard Specification for Magnesium Alloy Anodes for Cathodic Protection
• Effective Date: 01-May-2018
• Refers: ASTM B951-11(2018) - Standard Practice for Codification of Unalloyed Magnesium and Magnesium-Alloys, Cast and Wrought
• Effective Date: 01-May-2018
• Refers: ASTM E88-11(2017) - Standard Practice for Sampling Nonferrous Metals and Alloys in Cast Form for Determination of Chemical Composition
• Effective Date: 01-Sep-2017
• Refers: ASTM G97-97(2013) - Standard Test Method for Laboratory Evaluation of Magnesium Sacrificial Anode Test Specimens for Underground Applications
• Effective Date: 01-May-2013
• Refers: ASTM B951-11 - Standard Practice for Codification of Unalloyed Magnesium and Magnesium-Alloys, Cast and Wrought
• Effective Date: 01-Nov-2011
• Refers: ASTM E88-11 - Standard Practice for Sampling Nonferrous Metals and Alloys in Cast Form for Determination of Chemical Composition
• Effective Date: 01-May-2011
• Refers: ASTM B951-10 - Standard Practice for Codification of Unalloyed Magnesium and Magnesium-Alloys, Cast and Wrought
• Effective Date: 01-Feb-2010
• Refers: ASTM B951-09 - Standard Practice for Codification of Unalloyed Magnesium and Magnesium-Alloys, Cast and Wrought
• Effective Date: 01-Jun-2009
• Refers: ASTM E29-08 - Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
• Effective Date: 01-Oct-2008
• Refers: ASTM B951-08 - Standard Practice for Codification of Unalloyed Magnesium and Magnesium-Alloys, Cast and Wrought
• Effective Date: 01-Mar-2008
• Refers: ASTM G97-97(2007) - Standard Test Method for Laboratory Evaluation of Magnesium Sacrificial Anode Test Specimens for Underground Applications
• Effective Date: 01-Nov-2007
• Refers: ASTM B953-07 - Standard Practice for Sampling Magnesium and Magnesium Alloys for Spectrochemical Analysis
• Effective Date: 01-Jun-2007
• Refers: ASTM B954-07 - Standard Test Method for Analysis of Magnesium and Magnesium Alloys by Atomic Emission Spectrometry
• Effective Date: 01-Jun-2007
• Refers: ASTM B951-07 - Standard Practice for Codification of Unalloyed Magnesium and Magnesium-Alloys, Cast and Wrought
• Effective Date: 15-Apr-2007
• Refers: ASTM E29-06b - Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
• Effective Date: 15-Nov-2006

Overview

ASTM B843-18e1: Standard Specification for Magnesium Alloy Anodes for Cathodic Protection specifies the requirements for magnesium alloy anodes used in cathodic protection systems. Developed by ASTM International, this standard applies to anodes in the form of cast and extruded shapes. Magnesium anodes are widely used in industry to prevent corrosion of metal structures, such as pipelines, storage tanks, and marine equipment. This standard details requirements for chemical composition, sampling, quality, packaging, and ordering, ensuring consistent product performance and safety for cathodic protection applications.

Key Topics

• Material Forms: Covers magnesium alloy anodes produced as cast or extruded shapes.
• Chemical Composition: Specifies chemical requirements for various magnesium alloy grades, ensuring anodes meet defined purity and alloy content standards.
• Sampling and Analysis: Describes methods and timing for sampling magnesium materials, either from the molten metal or finished anodes, to verify chemical conformity.
• Surface Quality: Requires that the surface of magnesium anodes be clean and substantially free from dirt, slag, or any foreign materials, supporting prolonged performance in field installations.
• Ordering Requirements: Outlines essential information, such as grade, quantity, and size, to be provided in procurement orders.
• Packaging and Marking: Ensures magnesium anodes are properly packaged to prevent damage during handling and shipping. Packages must include labeling with order and manufacturer information for traceability.

Applications

ASTM B843-18e1 is critical for industries that rely on cathodic protection systems to prevent corrosion, especially in environments where metal structures are exposed to water, soil, or other corrosive agents. Typical applications of magnesium alloy anodes specified by this standard include:

• Underground Pipelines: Protection of steel pipelines for water, gas, and petroleum distribution.
• Storage Tanks: Internal and external corrosion prevention for aboveground and underground storage tanks.
• Marine Structures: Safeguarding marine vessels, offshore platforms, and coastal installations from corrosion in seawater environments.
• Industrial Equipment: Anodes used in heat exchangers, boilers, and other equipment exposed to aggressive or corrosive environments.

The use of standardized magnesium alloy anodes ensures predictable consumption rates, long-term reliability, effective cathodic protection, and reduced maintenance costs for asset owners.

Related Standards

For companies and professionals working in corrosion protection and materials engineering, the following related ASTM standards are frequently used alongside ASTM B843-18e1:

• ASTM B951: Practice for Codification of Unalloyed Magnesium and Magnesium Alloys, Cast and Wrought.
• ASTM B953: Practice for Sampling Magnesium and Magnesium Alloys for Spectrochemical Analysis.
• ASTM B954: Test Method for Analysis of Magnesium and Magnesium Alloys by Atomic Emission Spectrometry.
• ASTM E29: Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications.
• ASTM E55: Practice for Sampling Wrought Nonferrous Metals and Alloys for Determination of Chemical Composition.
• ASTM E88: Practice for Sampling Nonferrous Metals and Alloys in Cast Form for Determination of Chemical Composition.
• ASTM E527: Practice for Numbering Metals and Alloys in the Unified Numbering System (UNS).
• ASTM G97: Test Method for Laboratory Evaluation of Magnesium Sacrificial Anode Test Specimens for Underground Applications.

Compliance with ASTM B843-18e1 ensures alignment with international best practices and supports high standards of safety, reliability, and performance in critical cathodic protection projects.

Keywords: magnesium alloy anodes, cathodic protection, ASTM B843, corrosion prevention, standard specification, anode quality, material composition, industrial protection.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
´1
Designation:B843 −18
Standard Specification for
Magnesium Alloy Anodes for Cathodic Protection
This standard is issued under the fixed designation B843; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Editorial changes were made to Table 1 in June 2018.
1. Scope* 3. Significance and Use
3.1 This specification is prescriptive and not performance in
1.1 This specification covers magnesium alloy anodes in the
nature.
form of cast and extruded shapes.
1.2 This international standard was developed in accor-
4. Ordering Information
dance with internationally recognized principles on standard-
4.1 Orders for anodes under this specification shall include
ization established in the Decision on Principles for the
the following information:
Development of International Standards, Guides and Recom-
4.1.1 Grade (Section 5 and Table 1),
mendations issued by the World Trade Organization Technical
4.1.2 Quantity (number of pieces), and
Barriers to Trade (TBT) Committee.
4.1.3 Size, form, and shape as negotiated between purchaser
and supplier.
2. Referenced Documents
2.1 ASTM Standards:
5. Chemical Composition
B951 PracticeforCodificationofUnalloyedMagnesiumand
5.1 Limits—The material shall conform to the chemical
Magnesium-Alloys, Cast and Wrought
composition requirements prescribed in Table 1.
B953 Practice for Sampling Magnesium and Magnesium
Alloys for Spectrochemical Analysis 5.2 Sampling:
B954 Test Method for Analysis of Magnesium and Magne- 5.2.1 Sufficient samples shall be taken by the manufacturer
sium Alloys by Atomic Emission Spectrometry to ensure conformance to the chemical composition require-
ments of the metal. Samples may be taken from the molten
E29 Practice for Using Significant Digits in Test Data to
Determine Conformance with Specifications metal when the cast anode or extrusion ingot is poured
following Practice B953, or from the finished anode following
E55 Practice for Sampling Wrought Nonferrous Metals and
Alloys for Determination of Chemical Composition the requirements of Specifications B954, E55,or E88. Samples
shall be representative of the material.
E88 Practice for Sampling Nonferrous Metals and Alloys in
Cast Form for Determination of Chemical Composition 5.2.2 MethodofAnalysis—Anysuitablemethodofchemical
analysis may be used. In case of dispute, the results secured by
E527 Practice for Numbering Metals and Alloys in the
Unified Numbering System (UNS) Test Method B954 shall be the basis of acceptance. Rounding
of test results obtained shall be performed as directed inASTM
G97 Test Method for Laboratory Evaluation of Magnesium
SacrificialAnode Test Specimens for UndergroundAppli- E29, Standard Practice for Using Significant Digits in Test
DatatoDetermineConformancewithSpecifications,unlessan
cations
E527 Practice for Numbering Metals and Alloys in the alternative rounding method is specified by the customer or
Unified Numbering System (UNS) applicable material specification.
6. Property Testing
1 6.1 Sufficient samples may be taken for property testing as
This specification is under the jurisdiction of ASTM Committee B07 on Light
Metals and Alloys and is the direct responsibility of Subcommittee B07.04 on
negotiated between purchaser and supplier. Testing will be
Magnesium Alloy Cast and Wrought Products.
done in compliance with Test Method G97.
Current edition approved May 1, 2018. Published May 2018. Originally
approved in 1993. Last previous edition approved in 2013 as B843 – 13. DOI:
7. General Quality
10.1520/B0843-18E01.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
7.1 Magnesium cast and extruded anodes shall have a clean
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
surface an
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