GB/T 24523-2020 PDF English
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Metallic materials -- Test method for rapid indentation (Brinell type) hardness testing
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| GB/T 24523-2009 | English | 759 |
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Test method for rapid indentation (Brinell) hardness testing of metallic materials
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GB/T 24523-2020: PDF in English (GBT 24523-2020) GB/T 24523-2020
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.040.10
CCS H 22
Replacing GB/T 24523-2009
Metallic materials - Test method for rapid indentation
(Brinell type) hardness testing
ISSUED ON: NOVEMBER 19, 2020
IMPLEMENTED ON: JUNE 01, 2021
Issued by: State Administration for Market Regulation;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 3
Introduction ... 5
1 Scope ... 6
2 Normative references ... 6
3 Terms and definitions ... 6
4 Principle ... 7
5 Symbols and descriptions ... 7
6 Test equipment ... 8
7 Specimens ... 9
8 Test procedures ... 10
9 Determination of extreme hardness ... 10
10 Factors affecting the accuracy of measurement results ... 10
11 Test report ... 11
Annex A (normative) Inspection and calibration of rapid indentation (Brinell
type) hardness tester ... 12
Annex B (informative) Factors affecting the accuracy of measurement results
... 17
Metallic materials - Test method for rapid indentation
(Brinell type) hardness testing
1 Scope
This Standard specifies the principle, symbols, test equipment, specimens, test
procedures, determination of extreme hardness values, factors affecting the
accuracy of measurement results, and test reports for rapid indentation (Brinell
type) hardness testing of metallic materials.
This Standard is applicable to the rapid Brinell type hardness testing on the
parts on the production site by the rapid indentation (Brinell type) hardness
tester.
2 Normative references
The following referenced documents are indispensable for the application of
this document. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any
amendments) applies.
GB/T 231.1-2018, Metallic materials - Brinell hardness test - Part 1: Test
method
GB/T 231.2, Metallic materials - Brinell hardness test - Part 2: Verification
and calibration of testing machines
GB/T 231.3, Metallic materials - Brinell hardness test - Part 3: Calibration of
reference blocks
GB/T 13634, Metallic materials - Calibration of force-proving instruments
used for the verification of uniaxial testing machines
JJG 144, Verification Regulation of Standard Dynamometers
3 Terms and definitions
There are no terms and definitions that need to be defined in this document.
test force can also be used. If the initial test force is used, the size of the initial
test force is determined by the hardness tester manufacturer.
6.2.2 The indenter used for the rapid indentation (Brinell type) hardness test
shall be a tungsten carbide alloy ball that meets the requirements of GB/T 231.2.
6.3 Indentation depth measuring device
6.3.1 The indentation depth measuring device shall meet the requirements of
A.3.3.2. The method of measuring the indentation depth is determined by the
hardness tester manufacturer.
6.3.2 The display of the hardness tester shall include the measured indentation
depth value and the corresponding Brinell hardness value. The Brinell hardness
value displayed shall be the Brinell hardness value of the corresponding scale
converted from the measured indentation depth. The method of converting the
measured indentation depth into the Brinell hardness value is determined by
the hardness tester manufacturer.
7 Specimens
7.1 General requirements
The specimens tested by the rapid press-in (Brinell type) hardness tester are
mainly mass-produced parts that need to quickly test the Brinell hardness at
the production site. The parts can be flat or curved. Any part that can be tested
by the test method specified in GB/T 231.1-2018 can be tested with a rapid
indentation (Brinell type) hardness tester.
7.2 Specimen surface processing
In order to accurately measure the indentation depth, and to remove the surface
conditions (such as decarburization, oxide layer) that affect the authenticity of
the hardness measurement of the specimen, if necessary, the surface of the
specimen shall be polished, cut or polished. When processing the surface of
the specimen, attention shall be paid to minimize the impact on the surface
hardness of the specimen (for example, due to overheating or cold processing).
When using a supporting measuring table, the surface of the specimen in
contact with the measuring table shall be clean, and there shall be no conditions
that may affect the test results.
7.3 Specimen thickness
The thickness of the specimen shall be at least 8 times the total indentation
depth to ensure that there will be no bumps or other marks on the back of the
specimen caused by the test force. Under different hardness test conditions,
the relationship between the minimum thickness of the test specimen and the
indentation diameter can be found in Annex A of GB/T 231.1-2018.
8 Test procedures
8.1 Selection of test conditions
The selection of the total test force and the diameter of the indenter shall meet
the requirements of GB/T 231.1-2018. It shall be the same as the Brinell
hardness test conditions to be replaced.
8.2 Indentation interval
The distance from the center of the indentation to the edge of the sample or the
edge of another indentation shall be at least 2.5 times the diameter of the
indentation.
8.3 Application of test force
Move the indenter perpendicular to the surface of the specimen, without impact,
vibration and overloaded contacting the test surface. The axis of the indenter
and the direction of force shall be perpendicular to the test surface.
8.4 Indentation depth measurement
Measure the indentation depth according to the manufacturer's instructions.
When using this test method to detect the hardness of parts, it is recommended
to record the measured indentation depth value.
9 Determination of extreme hardness
The rapid indentation (Brinell type) hardness test is usually only used to
measure a limited range of Brinell hardness. In order to determine the
acceptable hardness extremes (maximum and minimum) for a given part, it
shall use a rapid indentation (Brinell type) hardness tester to measure samples
that represent the extreme value of the acceptable range. The measurement
result can be used as the extreme value of the measurement range of the rapid
indentation (Brinell type) hardness test.
10 Factors affecting the accuracy of measurement
results
Certain factors will affect the accuracy of the measurement results, see Annex
Annex A
(normative)
Inspection and calibration of rapid indentation (Brinell type) hardness
tester
A.1 General
A.1.1 There are three inspection methods for the rapid indentation (Brinell type)
hardness tester: direct inspection, indirect inspection and daily inspection.
A.1.2 Direct inspection is to directly measure the test force, indentation depth
measuring device and indenter and check whether the key parts of the
hardness tester are within the tolerance range.
A.1.3 Indirect inspection is to use standard hardness blocks or parts or samples
with known hardness to perform periodic inspection of the performance of the
hardness tester.
A.1.4 Daily inspection is to use standard hardness blocks or parts or samples
with known hardness, during the indirect inspection period, to monitor the
performance of the hardness tester.
NOTE 1: It may be necessary to refer to the manufacturer's instructions for some of the
inspections specified in this appendix.
NOTE 2: The sample is usually taken from the part to be tested.
A.2 General requirements
A.2.1 It shall, under the specified conditions, in accordance with the cycle
interval specified in Table A.1, or in the event of a situation that may affect the
performance of the hardness tester, inspect the hardness tester.
A.2.2 A thermometer with a resolution of at least 1°C shall be used to measure
the temperature of the inspection site. It is recommended to monitor the
temperature during the entire test period. Record and report significant
temperature changes. In daily inspections, there is no need to measure the
temperature of the inspection site.
A.2.3 When the user has traceability requirements, all measuring instruments
used for measurement in accordance with the requirements of this appendix
shall be traceable to national standards.
A.2.4 The indirect inspection of the hardness tester shall be carried out at the
A.4.6 The accuracy of the displayed value of the indentation depth specified in
6.3.2 shall meet the technical parameters given by the manufacturer. When the
rapid indentation (Brinell type) hardness tester shows the Brinell hardness
value, the deviation between the displayed value of each test and the marked
value of the standard hardness block or part (or sample) shall not be more than
3%.
A.5 Daily inspection
A.5.1 Daily inspection is an important means for users of the hardness tester to
monitor the performance of the hardness tester during the indirect test cycle.
As a minimum requirement, the daily inspection shall be performed on each
combination of total test force and indenter diameter to be used in accordance
with the schedule given in Table A.1.
A.5.2 The daily inspection procedure is the same as the indirect inspection.
However, daily inspection only requires the use of a standard hardness block
or a part (or sample) with a known hardness value for at least one test. The
maximum allowable deviation specified in A.4.5 and A.4.6 applies to daily
inspection. It is recommended that the hardness value of the standard hardness
block or part (or sample) used in daily inspection is close to the middle value of
the hardness range to be used. When it is necessary to detect curved parts,
parts (or samples) with known hardness with the same radius of curvature shall
be used to conduct daily inspection on the hardness tester.
A.6 Inspection report
A.6.1 General requirements
The inspection report shall be filled out by the inspector. Both direct inspection
and indirect inspection need to provide inspection report. No inspection report
is required for daily inspection.
A.6.2 Inspection report information
A.6.2.1 The inspection report for direct inspection shall contain the following
information:
a) Reference to this Standard;
b) The identification information of the rapid indentation (Brinell type)
hardness tester, including the model and serial number;
c) The identification information of all equipment used in the inspection,
including the identification information of the number and its value
traceability to the superior standard;
d) The temperature during inspection shall be at least 1°C;
e) The measurement results and calculation results used to determine
whether the hardness tester meets the inspection requirements;
f) If the hardness tester has been adjusted or repaired, a description of the
adjustment or repair;
g) Date of inspection and name of inspection agency;
h) Inspector identification information.
A.6.2.2 The inspection report of the indirect inspection shall contain the
following information:
a) Reference to this Standard;
b) The identification information of the rapid indentation (Brinell type)
hardness tester, including the model and serial number;
c) The identification information of all equipment used in the inspection,
including the identification information of the number and its value
traceability to the superior standard;
d) The temperature during inspection shall be at least 1°C;
e) The combination of tested test force and indenter;
f) The measurement results and calculation results used to determine
whether the hardness tester meets the inspection requirements;
g) If the hardness tester has been adjusted or repaired, a description of the
adjustment or repair;
h) Date of inspection and name of inspection agency;
i) Inspector identification information.
A.6.3 Daily inspection
Daily inspection does not require inspection report. It is recommended to keep
daily inspection records, including inspection date, measurement results,
calibration value of standard hardness block, standard hardness block number,
and identification information of the inspector. These records can be used to
evaluate the long-term performance of the hardness tester.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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