ASTM E977-05

Standard Practice for Thermoelectric Sorting of Electrically Conductive Materials

ABSTRACT
This practice covers the procedure for sorting electrically conductive materials using the thermoelectric method, which is based on the seebeck effect. The procedure relates to the use of direct- and comparator-type thermoelectric instruments for distinguishing variations in materials which affect the thermoelectric properties of those materials. The two techniques that are primarily used in thermoelectric sorting are direct and comparative instrumentation. In the direct instruments, equipment is standardized by placing materials with known chemistry and metallurgical structure in the test system. In the comparative instruments, the thermoelectric response of the test piece is compared with that of a known standard(s) and the response indicates whether the piece is within the acceptance limits. The electronic apparatus shall be capable of maintaining a sufficient temperature differential across the electrodes to produce a suitable thermoelectric voltage. The different procedures for sorting electrically conductive materials are presented in details.
SCOPE
1.1 This practice covers the procedure for sorting materials using the thermoelectric method, which is based on the Seebeck effect. The procedure relates to the use of direct- and comparator-type thermoelectric instruments for distinguishing variations in materials which affect the thermoelectric properties of those materials.
1.2 While the practice is most commonly applied to the sorting of metals, it may be applied to other electrically conductive materials.
1.3 Thermoelectric sorting may also be applied to the sorting of materials on the basis of plating thickness, case depth, and hardness.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 30-Jun-2005
• ICS: 29.050 - Superconductivity and conducting materials
• Technical Committee: E07 - Nondestructive Testing
• Drafting Committee: E07.10 - Specialized NDT Methods

Relations

• Replaces: ASTM E977-84(1999) - Standard Practice for Thermoelectric Sorting of Electrically Conductive Materials
• Effective Date: 01-Jul-2005
• Replaced By: ASTM E977-05(2010) - Standard Practice for Thermoelectric Sorting of Electrically Conductive Materials
• Effective Date: 01-Jun-2010
• Referred By: ASTM E1916-11(2019) - Standard Guide for Identification of Mixed Lots of Metals
• Effective Date: 01-Jul-2005
• Referred By: ASTM E1476-04(2022) - Standard Guide for Metals Identification, Grade Verification, and Sorting
• Effective Date: 01-Jul-2005

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E977–05
Standard Practice for
1
Thermoelectric Sorting of Electrically Conductive Materials
This standard is issued under the fixed designation E977; 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.
1. Scope tors at two points of different temperatures. The magnitude of
this emf is a function of the chemistry of the materials, surface
1.1 This practice covers the procedure for sorting materials
metallurgical structure, and the temperature at the junctions.
using the thermoelectric method, which is based on the
See Fig. 1.
Seebeck effect. The procedure relates to the use of direct- and
comparator-type thermoelectric instruments for distinguishing
3. Summary of Practice
variations in materials which affect the thermoelectric proper-
3.1 The two techniques that are primarily used in thermo-
ties of those materials.
electric sorting are direct and comparative instrumentation. In
1.2 While the practice is most commonly applied to the
the direct instruments, equipment is standardized by placing
sorting of metals, it may be applied to other electrically
materials with known chemistry and metallurgical structure in
conductive materials.
the test system. The value of the thermoelectric voltage (or
1.3 Thermoelectric sorting may also be applied to the
arbitrary unit) is read on the scale of an indicator. In the
sorting of materials on the basis of plating thickness, case
comparative instruments, the thermoelectric response of the
depth, and hardness.
test piece is compared with that of a known standard(s) and the
1.4 This standard does not purport to address all of the
response indicates whether the piece is within the acceptance
safety concerns, if any, associated with its use. It is the
limits.
responsibility of the user of this standard to establish appro-
3.1.1 Both kinds of instrumentation require comparing the
priate safety and health practices and determine the applica-
pieces to be examined with the known standard(s). Two or
bility of regulatory limitations prior to use.
more samples representing the acceptance limits may be
2. Terminology required.
3.1.2 Direct Thermoelectric Instrumentation—a known
2.1 Descriptions of Terms:
standard(s) is inserted in the system and the controls of the
2.1.1 acceptance limits—the thermoelectric response that
instrument are adjusted to obtain a voltage (or arbitrary unit)
establishes the group into which the material being examined
reading(s). The process is then continued by inserting the
belongs.
pieces to be sorted into the system, and observing the instru-
2.1.2 comparative instrumentation—a system that uses
ment reading(s).
electrode assemblies (probes), associated electronics, and
3.1.3 Comparative Instrumentation—Known standards rep-
known standards to measure a thermoelectric response from an
resenting the acceptance limits are inserted into the system.
electrically-conductive material. This response is compared
The instrument controls are adjusted for appropriate response.
with that of the reference standard.
The process is then continued by inserting the pieces to be
2.1.3 direct instrumentation—a system that specifically
sorted in the system, and observing the instrument response.
measures and displays the voltage (or an arbitrary unit)
3.2 In both instruments, the range of the instrument re-
generated between the electrodes when they are at different
sponse must be adjusted during standardization so that any
temperatures and in contact with the material.
anticipated deviation from the known standard(s) will be
2.1.4 electrode—the conductors used in thermoelectric sort-
recognized as within the required acceptance limits.
ing instruments used to generate the Seebeck effect with the
3.3 The examination process may consist of manual inser-
material under test.
tion of one piece after another into the system, or an automated
2.1.5 Seebeckeffect—thethermoelectricelectromotiveforce
feeding and classifying mechanism may be employed.
(emf) produced in a circuit connecting two dissimilar conduc-
4. Application
1
This practice is under the jurisdiction of ASTM Committee E07 on Nonde-
4.1 Thermoelectric techniques provide a method for sorting
structive Testing and is the direct responsibility of Subcommittee E07.10 on
large quantities of conductive materials. The ability to accom-
Emerging NDT Methods.
plishsatisfactorilythesetypesofseparationsisdependentupon
Current edition approved July 1, 2005. Published July 2005. Originally approved
in 1984. Last previous edition approved in 1999 as E977 - 84 (1999). DOI:
10.1520/E0977-05.
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