ASTM B648-23

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.
Designation: B648 − 23
Standard Test Method for
Indentation Hardness of Aluminum Alloys by Means of a
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Barcol Impressor
This standard is issued under the fixed designation B648; 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 3. Terminology
3.1 Definitions—The definitions of terms relating to hard-
1.1 This test method covers the determination of indentation
hardness of aluminum alloys using a Barcol Impressor. ness testing appearing in Terminology E6 shall be considered
as applying to the terms used in this test method.
1.2 The values stated in SI units are to be regarded as
standard. The values given in parentheses after SI units are
4. Significance and Use
provided for information only and are not considered standard.
4.1 The Barcol Impressor is portable and therefore useful
1.2.1 Some Barcol Impressors are for use on plastics and are
for in situ determination of the hardness of fabricated parts and
not included in this test method and should not be used for
individual test specimens for production control purposes.
aluminum alloys.
4.2 This test method should be used only as cited in
1.3 This standard does not purport to address all of the
applicable material specifications.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5. Apparatus
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
5.1 Barcol Impressor—See Fig. 1.
1.4 This international standard was developed in accor-
5.2 Indentor—The indentor shall consist of a hardened steel
dance with internationally recognized principles on standard-
truncated cone having an angle of 26° with a flat tip 0.157 mm
ization established in the Decision on Principles for the
(0.0062 in.) in diameter. It shall fit into a hollow spindle and be
Development of International Standards, Guides and Recom-
held down by a spring-loaded plunger. See Fig. 1.
mendations issued by the World Trade Organization Technical
5.3 Indicating Device—The indicating dial shall have 100
Barriers to Trade (TBT) Committee.
divisions, each representing a depth of 0.0076 mm
(0.00030 in.) penetration. The higher the reading, the harder
2. Referenced Documents
the material.
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2.1 ASTM Standards:
E6 Terminology Relating to Methods of Mechanical Testing
6. Test Parts or Specimen
E10 Test Method for Brinell Hardness of Metallic Materials
6.1 The testing area shall be smooth, clean, and free of
E18 Test Methods for Rockwell Hardness of Metallic Ma-
mechanical damage. The surface may be lightly polished to
terials
eliminate scratches or die lines. It shall be such that it can be
E177 Practice for Use of the Terms Precision and Bias in
essentially perpendicular to the indentor during the test.
ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to
NOTE 1—The effect of curvature of the test specimen on the Barcol
Impressor readings is presented in Appendix X1, Fig. X1.1.
Determine the Precision of a Test Method
6.2 Dimensions—Test parts or specimens shall be at least
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1.5 mm ( ⁄16 in.) thick and large enough to ensure a minimum
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1 distance of 3 mm ( ⁄8 in.) in any direction from the indentor
This test method is under the jurisdiction of ASTM Committee B07 on Light
Metals and Alloys and is the direct responsibility of Subcommittee B07.05 on point to the edge.
Testing.
Current edition approved June 1, 2023. Published June 2023. Originally
7. Calibration
ɛ1
approved in 1978. Last previous edition approved in 2015 as B648 – 10 (2015) .
DOI: 10.1520/B0648-23.
7.1 With the plunger upper guide backed out until it just
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
engages the spring, place the impressor on a glass surface and
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
press down until the penetrator point is forced all the way back
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. into the lower plunger guide. The indicator should then read
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B648 − 23
FIG. 1 Diagram of Typical Barcol Impressor Arrangement
100 6 1. If it does not, loosen the locknut and turn the lower 0.5 division. Take care to avoid s
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