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GB/T 231.1-2009 English PDF (GBT231.1-2009)

GB/T 231.1-2009 English PDF (GBT231.1-2009)

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GB/T 231.1-2009: Metallic materials -- Brinell hardness test -- Part 1: Test method

This Part of GB/T 231 specifies metallic Brinell hardness test principle, symbols and explanations, test equipment, test specimen, test procedures, test results uncertainty and test report.
GB/T 231.1-2009
GB
NATIONAL STANDARD OF
THE PEOPLE REPUBLIC OF CHINA
ICS 77.040.10
H 22
Replacing GB/T 231.1-2002
Metallic materials - Brinell hardness test -
Part 1. Test method
(ISO 6506-1.2005, MOD)
ISSUED ON. JUNE 25, 2009
IMPLEMENTED ON. APRIL 1, 2010
Issued by. General Administration of Quality Supervision, Inspection and Quarantine;
Standardization Administration Committee.
Table of Contents
Foreword ... 3
Introduction ... 5
1 Scope ... 6
2 Normative references ... 6
3 Principle... 6
4 Symbols and explanations... 7
5 Test method ... 8
6 Test specimen ... 8
7 Test procedures ... 9
8 Uncertainty of results ... 12
9 Test report ... 12
Annex A ... 13
Annex B ... 14
Annex C ... 16
Foreword
GB/T 231 Metallic materials - Brinell hardness test consists of the following four parts.
- Part 1. Test method;
- Part 2. Verification and calibration of testing machines;
- Part 3. Calibration of hardness reference blocks;
- Part 4. Tables of hardness values.
This Part is the first part of GB/T 231.
This Part?€?s modification adopts the International standard ISO 6506-1.2005 Metallic materials -- Brinell hardness test -- Part 1. Test method (English version).
This Part was drafted in accordance with ISO 6506-1.2005. Based on China's actual situation, this Part modified and supplemented during the use of the International standard. These technical differences were marked by vertical single line in the margins of the terms to which they relate.
This Part is basically same with ISO 6506-1.2005 in structure and technical content. Based on China's actual situation, this Part made modifications in the following aspects.
- deleted the foreword of the International standard;
- replaced ?€?this International Standard?€? by ?€?this Standard?€?;
- used decimal point ?€?.?€? to replace ?€?,?€? which was used as decimal point; - deleted ISO 4498-1 from normative references;
- added suggestion on surface roughness of specimen in sub-clause 6.1 of Clause 6;
- modified uncertainty in measurement of hardness values in Annex C of
ISO 6506-1.2005.
This Part replaces GB/T 231.1-2002 Metallic materials -- Brinell hardness test -- Part 1. Test method. Compared with GB/T 231.1-2002, this Part made the following modifications.
- added the foreword;
Metallic materials - Brinell hardness test -
Part 1. Test method
1 Scope
This Part of GB/T 231 specifies metallic Brinell hardness test?€?s principle, symbols and explanations, test equipment, test specimen, test procedures, test results uncertainty and test report.
The upper limit of the Brinell hardness test range specified in this Part is 650 HBW.
Brinell hardness test of special materials or products shall be specified in relevant standards.
2 Normative references
The following standards contain the provisions which, through reference in this Part of GB/T 231, constitute the provisions of this Part. For dated references, subsequent amendments (excluding corrections) or revisions do not apply to this Part. However, the parties who enter into agreement based on this Part are encouraged to investigate whether the latest versions of these documents are applicable. For undated reference documents, the latest versions apply to this Part.
GB/T 231.2 Metallic Brinell hardness test - Part 2. Verification and
calibration of hardness testers (GB/T 231.2-2002, ISO 6506-2.1999, MOD); GB/T 231.3 Metallic Brinell hardness test - Part 3. Calibration of hardness reference blocks (GB/T 231.3-2002, ISO 6506-3.1999, MOD);
GB/T 231.4 Metallic materials - Brinell hardness test - Part 4. Tables of hardness values (GB/T 231.4-2009, ISO 6506-4.2005, MOD)
JJF 1059 Evaluation and Expression of Uncertainty in Measurement
3 Principle
Apply the test force to a carbide ball of a certain diameter into specimen surface. After the prescribed holding time, remove the test force, measuring the diameter of specimen surface indentation (see Figure 1).
- the average of multiple measurements at equal intervals;
- the numerical value of the surface area of indentation.
7.9 GB/T 231.4 contains a calculation table of plane Brinell hardness value used to determine the hardness of the plane specimen.
8 Uncertainty of results
If necessary, a complete assessment of the uncertainty should be based on the uncertainty of measurement guide JJF 1059.
For hardness test, there are two possible ways of assessing the measurement uncertainty.
- Assessment of all the relevant uncertainty components present based on the direct calibration.
- Indirect calibration based on standard hardness blocks (certified
reference material); refer to Appendix C for guidance on measurement.
9 Test report
The test report should contain the following information.
a) reference to this Part of GB/T 231;
b) a detailed description of specimen;
c) if the test temperature is not 10??C ~ 35??C, it should indicate the test temperature;
d) test results;
e) operation not within the scope of this Part;
f) various details which affect the test results.
NOTE 1 There is no universally applicable precise method to convert the Brinell hardness value to other hardness or tensile strength. These conversions should be avoided unless the relevant conversion basis is obtained through a comparative test or as otherwise specified in the product standard.
NOTE 2 It should pay attention to the anisotropy of material, e.g., after a large amount of cold deformation, so that indentation diameter in different directions may have greater differences. The product technical conditions should specify the limits of this difference. C.4 Steps to calculate uncertainty. hardness measurement value
NOTE Certified Reference Material refers to the standard hardness block calibrated by standard hardness tester.
C.4.1 Method of considering the maximum tolerance of hardness tester
(Method 1)
Method 1 is simple. It does not consider the system error of hardness tester, i.e., a method based on the maximum tolerance of hardness tester.
Determine the extended uncertainty U (see Table C.1).
C.4.2 Method of considering the system error of hardness tester
(Method 2)
In addition to Method 1, it can select Method 2. Method 2 is about control flow and it may obtain a smaller degree of uncertainty.
C.5 Representation of hardness measurement results
When representing measurement results, it should indicate the representation method of uncertainty. Method 1 is often used to express the measurement uncertainty (See Table C.1, 10th step).
Measurement
results.
Measurement
results.
Method 1
Method 2
Difference between hardness
tester calibration value and
hardness block standard value
b Step 3 and Step 5
Method 1
Method 2
Uncertainty brought by system
error of hardness tester ub Two-point distribution ub = 0.6
Method 1
Method 2
Evaluation of extended
uncertainty U
Step 1 ~ Step 7
K = 2
Method 1
Method 2
Measurement results X Step 1 ~ Step 10 (Method 1)
Method 1
Method 2
Evaluation of extended
uncertainty U
Step 1 ~ Step 5
Step 7 ~ Step 9
Method 1
Method 2
Measurement results X Step 1 and Step 12
(Method 2)

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