ASTM A340 Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
What is ASTM A340?
ASTM A340 is a reference terminology standard for numerous ASTM magnetic property test methods and should be used together with the applicable magnetic testing standard rather than as a standalone testing procedure. ASTM A340 is the standard terminology of symbols and definitions relating to Magnetic Testing Committee A06 on magnetic properties. The standard describes a standardized terminology for magnetic properties, measurement parameters, symbols, and reporting conventions. Definitions for magnetic quantities, such as magnetic flux density (B), magnetic field strength (H), permeability (μ), coercivity (Hc), remanence (Br), hysteresis, energy product, and additional symbols used throughout the ASTM magnetic testing standards are included.
Why is a Consistent Terminology for Magnetic Properties Required?
The use of consistent terminology is key to the proper interpretation of the results of magnetic tests between laboratories, manufacturers, and research organizations. ASTM A340 establishes standardized symbols, definitions, abbreviations, and SI units to promote consistent communication and interpretation among ASTM magnetic testing standards. Adopting the ASTM A340 terminology can help to keep magnetic measurements and documentation clear, consistent, and easily understood around the world.
ASTM A340 Complete Guide
ASTM A340 provides the common terminology for performing, documenting, and interpreting magnetic testing. The standardized terminology helps ensure consistent interpretation across ASTM magnetic property test methods and technical documentation.
Other referenced ASTM standards include ASTM E3 and E381.
Standardization of Symbols
Establishes internationally recognized symbols for magnetic quantities, including magnetic flux density, magnetic field strength, permeability, coercivity, and remanence.
Terminology Reference
Defines standardized terminology used throughout laboratory reports, engineering documentation, and ASTM magnetic testing standards.
Unit Standardization
Introduces SI units and offers guidance when using older, Gaussian terms in technical literature.
Technical Documentation
Facilitates uniform preparation, interpretation, and communication of magnetic testing reports and engineering specifications.
ASTM A340 Magnetic Measurement SystemÂ
What is the Scope of ASTM A340 Standard?
ASTM A340 provides a unified set of symbols, terminology, abbreviations, and definitions for magnetic testing and magnetic property evaluation. The standard is a common technical language for the reporting and interpretation of magnetic measurement results throughout ASTM magnetic testing standards and engineering documentation-
Specifies agreed-upon symbols for magnetic testing.
Defines magnetic properties and parameters.
Promotes consistent terminology used throughout ASTM magnetic testing standards.
Promotes the use of SI units for measuring magnetism.
Supports reporting and interpretation of magnetic test results.
Supports engineers, laboratories, manufacturers, and researchers through consistent technical communication.
Provides standardized terminology and symbols used in magnetic testing documentation.
Specific Terminologies Mentioned In ASTM A340
The ASTM A340 standard establishes standardized terminology for reporting and recording magnetic measurements. ASTM A340 is referenced by laboratories conducting magnetic property measurements in other ASTM standards to ensure uniformity in use of symbols, definitions, and units and in the technical descriptions. The terms in the ASTM A340 standards for magnetic properties are frequently used in test reports to describe magnetic field strength, magnetic flux density, permeability, coercivity, remanence, and hysteresis characteristics of magnetic materials.
Symbols/Terms
Definition
Magnetic Flux Density (B)
The amount of magnetic flux passing through a unit area of a material, expressed in tesla (T).
Magnetic Field Strength (H)
The magnetizing force applied to a magnetic material, typically expressed in amperes per meter (A/m).
Magnetic Flux (Φ)
The total magnetic flux that passes through a given area of a magnetic circuit.
Residual Flux Density (Br)
The magnetic flux density remaining in a previously saturated magnetic material after the applied magnetic field has been reduced to zero.
Coercive Field Strength (Hc)
The magnetic field required to reduce the residual magnetic flux density of a magnetized material to zero.
Saturation Flux Density (Bs)
The maximum magnetic flux density that a material can attain under an applied magnetic field.
Permeability (μ)
The property of a material that indicates the relationship between magnetic flux density (B) and magnetic field strength (H), describing how readily the material becomes magnetized.
Relative Permeability (μr)
The ratio of a material’s permeability to the permeability of free space.
What is the Use of ASTM A340?
ASTM A340 provides a standard set of symbols, definitions, abbreviations, and units to establish a common technical language for magnetic testing throughout ASTM magnetic standards. This standard ensures that magnetic properties are understood consistently by engineers, laboratories, manufacturers, and researchers, enhancing the accuracy and uniformity of technical documentation and test reports. ASTM A340 standard-
Sets standards for the symbols and terms of magnetic testing.
Provides consistent magnetic property measurement reporting
Promotes communication between labs, manufacturers, and researchers.
Provides reference information for ASTM magnetic testing standards.
Encourages adoption of SI units for magnetic units.
Supports the preparation of technical reports, specifications, and engineering documentation.
Consistent terminology improves technical communication among manufacturers, laboratories, researchers, customers, and regulatory organizations by reducing ambiguity in the reporting of magnetic properties.
What does ASTM A340 have to say about magnetic testing?
Reliable magnetic tests depend not only on the accuracy of the measurements but also on the consistent application of technical terms. ASTM A340 provides a standard for magnetic symbols, definitions, and units to prevent confusion when reporting magnetic attributes like magnetic flux density, permeability, coercivity, remanence, and hysteresis. The standard facilitates communication among the manufacturer, testing laboratories, researchers, equipment suppliers, and end users, while maintaining uniformity between the various ASTM magnetic testing standards.
What is the Significance of ASTM A340 Standard?
The variety of terms, symbols, and measurement units used in magnetic testing from laboratory to laboratory, industry to industry, or technical publication to technical publication is one of the most frequent problems. Historical references are often given in Gaussian (CGS) units, while more modern specifications are generally given in SI units, and this can cause problems when interpreting the data. ASTM A340 provides consistent terminology and reporting, and reduces the potential for errors from inconsistent technical language and/or unit conversions. ASTM A340 is periodically reviewed and updated to maintain consistency with evolving magnetic measurement terminology and internationally accepted technical definitions.
How Do These Terminologies Help Reporting Analysis Results?
The results obtained using related ASTM magnetic tests can be reported in units including tesla (T) for magnetic flux density, ampere per meter (A/m) for magnetic field strength, henry per meter (H/m) for permeability, joule per cubic meter (J/m³) for energy product, and other standard SI units.Â
ASTM A340 promotes consistent interpretation of magnetic properties by providing standardized terminology and symbols.
Gokula Srinivasan Selvam is a Material Testing Associate at Matestlab Inc. and holds a postgraduate degree in Ceramic Engineering from IIT (BHU), Varanasi. His academic background and professional experience are centered on advanced ceramic materials, their processing, characterization, and performance evaluation. Know More
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