Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
GB/T 231 consists of the following parts, under the general title Metallic materials - Brinell hardness test:
——Part 1: Test method;
——Part 2: Verification and calibration of testing machines;
——Part 3: Calibration of reference blocks;
——Part 4: Table of hardness values.
This is Part 1 of GB/T 231.
This part is developed in accordance with the rules given in GB/T 1.1-2009.
This part replaces GB/T 231.1-2009 Metallic materials - Brinell hardness test - Part 1: Test method. Compared with GB/T 231.1-2009, the main technical changes in this standard are as follows:
——JJG 150 The metallic Brinell hardness testing machines is added for reference (see Clause 5);
——Requirement "prior to test, the state of hardness testing machine shall be verified according to Annex B" is added (see 7.2);
——"If the diameter of the indentation lies outside these limits, the ratio of indentation diameter to indenter diameter (d/D) shall be stated in the test report" is added (see 7.4);
——Requirement "the optical measurement of the indentation diameter may be performed with either a manual or an automatic measuring system" is specified (see 7.9; 7.8 of Edition 2009);
——The rounding requirement for hardness result is added (see 7.10; 7.9 of Edition 2009);
——Annex B is revised from informative to normative (see Annex B; Annex A of Edition 2009);
——The content related to uncertainty of the measured hardness values is modified (see Annex C).
This part is modified in relation to ISO 6506-1: 2014 Metallic materials - Brinell hardness test - Part 1: Test method.
This part has basically consistent structure with ISO 6506-1: 2014. Technical differences between this part and ISO 6506-1: 2014 are marked with perpendicular single line (|) in the outside page margin of the provisions concerned. Compared with ISO 6504-1: 2014, technical differences and their reasons are as follows:
——The adjustment in "Normative References" of this part has technical differences to meet the technical specification in China; the adjustment situations are embodied in a concentrated way in Clause 2 - "Normative references" and the specific adjustments are as follows:
ISO 6506-2 is replaced by GB/T 231.2 modified by adopting international standard (see Clause 5 and Annex A);
ISO 6506-3 is replaced by GB/T 231.3 modified by adopting international standard (see Annex A);
GB/T 231.4 identical to the international standard is used to replace ISO 6506-4 (see 7.10);
GB/T 9097 identical to the international standard is used to replace ISO 4498 (see Table 3);
JJG 150 is added for reference (see Clause 5).
The following editorial changes are also made in this part:
——Annexes A and B are adjusted in the order in which they appear in the standard.
This part was proposed by China Iron and Steel Association.
This part is under the jurisdiction of the National Technical Committee on Iron and Steel of Standardization Administration of China (SAC/TC 183).
The previous editions of this part are as follows:
——GB/T 231-1962, GB/T 231-1984, GB/T 231.1-2002 and GB/T 231.1-2009.
Metallic materials - Brinell hardness test - Part 1: Test method
1 Scope
This part of GB/T 231 specifies the principle, symbols and definitions, apparatus, test piece, procedure, uncertainty of the results and test report for Brinell hardness test of metallic materials.
This part is applicable to both fixed location and portable hardness testing machines. Brinell hardness test of special materials or products may be conducted by reference to GB/T 9097 and this part.
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 231.2-2012 Metallic materials - Brinell hardness test - Part 2: Verification and calibration of testing machines (GB/T 231.2-2012, ISO 6506-2: 2005, MOD)
GB/T 231.3 Metallic materials - Brinell hardness test - Part 3: Calibration of reference blocks (GB/T 231.3-2012, ISO 6506-3: 2005, 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, IDT)
GB/T 9097 Sintered metal materials, excluding hardmetals - Determination of apparent hardness and microhardness (GB/T 9097-2016, ISO 4498: 2010, IDT)
JJG 150 The Metallic Brinell Hardness Testing Machines
3 Principle
3.1 An indenter (tungsten carbide alloy indenter with diameter, D) is forced into the surface of a test piece and, after removal of the force, F, the diameter of the indentation, d, left in the surface is measured.
3.2 The Brinell hardness is proportional to the quotient obtained by dividing the test force by the curved surface area of the indentation. The indentation is assumed to take the shape of the unloaded ball indenter, and its surface area is calculated from the mean indentation diameter and the ball diameter, using the formula given in Table 1.
Figure 1 Principle of test
4 Symbols and definitions
4.1 See Figure 1 and Table 1.
Table 1 Symbols and definitions
Symbol Definition Unit
D Diameter of the ball mm
F Test force N
d Mean diameter of the indentation,
mm
d1, d2 Indentation diameters measured at approximately 90° mm
h Depth of indentation,
mm
HBW
0.102×F/D2 Force-diameter index N/mm2
Note: constant=0.102≈ , where 9.80665 is the conversion factor from kgf to N, in s/m2.
4.2 The following is an example of the designation of Brinell hardness, HBW:
Example:
5 Test apparatus
5.1 Hardness testing machine
The hardness testing machine shall be capable of applying a predetermined test force or test forces within the range of 9.807N to 29.42kN, in accordance with GB/T 231.2 or JJG 150.
5.2 Indenter
The tungsten carbide alloy indenter shall comply with the requirements of GB/T 231.2 or JJG 150.
5.3 Indentation measuring device
The indentation measuring device shall comply with the requirements of GB/T 231.2 or JJG 150.
6 Test piece
6.1 The test shall be carried out on a surface which is smooth and even; free from oxide scale, foreign matter, and, in particular, free from lubricants. The test piece shall have a surface finish that will allow an accurate measurement of the diameter of the indentation.
Note: for indentations made with the smaller ball indenters, it might be necessary to polish or lap the surface of test piece.
6.2 Preparation shall be carried out in such a way that any alteration of the surface, for example, due to excessive heating or cold-working, is minimized.
6.3 The thickness of the test piece shall be at least eight times the depth of indentation. Values for the minimum thickness of the test piece in relation to the mean diameter of indentation are given in Annex A. After test, visible deformation at the back of the test piece can indicate that the test piece is too thin.
7 Test procedure
7.1 In general, the test shall be carried out at ambient temperature within the limits of 10℃~35℃. For the tests requiring strictly on temperature, the temperature is 23℃±5℃.
7.2 Prior to test, the state of hardness testing machine shall be verified according to Annex B.
7.3 The test forces given in Table 2 shall be used. Other test forces and force-diameter indices may also be used by special agreement.
Foreword i 1 Scope 2 Normative references 3 Principle 4 Symbols and definitions 5 Test apparatus 6 Test piece 7 Test procedure 8 Uncertainty of results 9 Test report Annex A (Normative) Minimum thickness of the test piece in relation to the mean diameter of indentation Annex B (Normative) Procedure for periodic checking of the hardness testing machine by the user Annex C (Informative) Uncertainty of the measured hardness values Bibliography
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
GB/T 231 consists of the following parts, under the general title Metallic materials - Brinell hardness test:
——Part 1: Test method;
——Part 2: Verification and calibration of testing machines;
——Part 3: Calibration of reference blocks;
——Part 4: Table of hardness values.
This is Part 1 of GB/T 231.
This part is developed in accordance with the rules given in GB/T 1.1-2009.
This part replaces GB/T 231.1-2009 Metallic materials - Brinell hardness test - Part 1: Test method. Compared with GB/T 231.1-2009, the main technical changes in this standard are as follows:
——JJG 150 The metallic Brinell hardness testing machines is added for reference (see Clause 5);
——Requirement "prior to test, the state of hardness testing machine shall be verified according to Annex B" is added (see 7.2);
——"If the diameter of the indentation lies outside these limits, the ratio of indentation diameter to indenter diameter (d/D) shall be stated in the test report" is added (see 7.4);
——Requirement "the optical measurement of the indentation diameter may be performed with either a manual or an automatic measuring system" is specified (see 7.9; 7.8 of Edition 2009);
——The rounding requirement for hardness result is added (see 7.10; 7.9 of Edition 2009);
——Annex B is revised from informative to normative (see Annex B; Annex A of Edition 2009);
——The content related to uncertainty of the measured hardness values is modified (see Annex C).
This part is modified in relation to ISO 6506-1: 2014 Metallic materials - Brinell hardness test - Part 1: Test method.
This part has basically consistent structure with ISO 6506-1: 2014. Technical differences between this part and ISO 6506-1: 2014 are marked with perpendicular single line (|) in the outside page margin of the provisions concerned. Compared with ISO 6504-1: 2014, technical differences and their reasons are as follows:
——The adjustment in "Normative References" of this part has technical differences to meet the technical specification in China; the adjustment situations are embodied in a concentrated way in Clause 2 - "Normative references" and the specific adjustments are as follows:
ISO 6506-2 is replaced by GB/T 231.2 modified by adopting international standard (see Clause 5 and Annex A);
ISO 6506-3 is replaced by GB/T 231.3 modified by adopting international standard (see Annex A);
GB/T 231.4 identical to the international standard is used to replace ISO 6506-4 (see 7.10);
GB/T 9097 identical to the international standard is used to replace ISO 4498 (see Table 3);
JJG 150 is added for reference (see Clause 5).
The following editorial changes are also made in this part:
——Annexes A and B are adjusted in the order in which they appear in the standard.
This part was proposed by China Iron and Steel Association.
This part is under the jurisdiction of the National Technical Committee on Iron and Steel of Standardization Administration of China (SAC/TC 183).
The previous editions of this part are as follows:
——GB/T 231-1962, GB/T 231-1984, GB/T 231.1-2002 and GB/T 231.1-2009.
Metallic materials - Brinell hardness test - Part 1: Test method
1 Scope
This part of GB/T 231 specifies the principle, symbols and definitions, apparatus, test piece, procedure, uncertainty of the results and test report for Brinell hardness test of metallic materials.
This part is applicable to both fixed location and portable hardness testing machines. Brinell hardness test of special materials or products may be conducted by reference to GB/T 9097 and this part.
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 231.2-2012 Metallic materials - Brinell hardness test - Part 2: Verification and calibration of testing machines (GB/T 231.2-2012, ISO 6506-2: 2005, MOD)
GB/T 231.3 Metallic materials - Brinell hardness test - Part 3: Calibration of reference blocks (GB/T 231.3-2012, ISO 6506-3: 2005, 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, IDT)
GB/T 9097 Sintered metal materials, excluding hardmetals - Determination of apparent hardness and microhardness (GB/T 9097-2016, ISO 4498: 2010, IDT)
JJG 150 The Metallic Brinell Hardness Testing Machines
3 Principle
3.1 An indenter (tungsten carbide alloy indenter with diameter, D) is forced into the surface of a test piece and, after removal of the force, F, the diameter of the indentation, d, left in the surface is measured.
3.2 The Brinell hardness is proportional to the quotient obtained by dividing the test force by the curved surface area of the indentation. The indentation is assumed to take the shape of the unloaded ball indenter, and its surface area is calculated from the mean indentation diameter and the ball diameter, using the formula given in Table 1.
Figure 1 Principle of test
4 Symbols and definitions
4.1 See Figure 1 and Table 1.
Table 1 Symbols and definitions
Symbol Definition Unit
D Diameter of the ball mm
F Test force N
d Mean diameter of the indentation,
mm
d1, d2 Indentation diameters measured at approximately 90° mm
h Depth of indentation,
mm
HBW
0.102×F/D2 Force-diameter index N/mm2
Note: constant=0.102≈ , where 9.80665 is the conversion factor from kgf to N, in s/m2.
4.2 The following is an example of the designation of Brinell hardness, HBW:
Example:
5 Test apparatus
5.1 Hardness testing machine
The hardness testing machine shall be capable of applying a predetermined test force or test forces within the range of 9.807N to 29.42kN, in accordance with GB/T 231.2 or JJG 150.
5.2 Indenter
The tungsten carbide alloy indenter shall comply with the requirements of GB/T 231.2 or JJG 150.
5.3 Indentation measuring device
The indentation measuring device shall comply with the requirements of GB/T 231.2 or JJG 150.
6 Test piece
6.1 The test shall be carried out on a surface which is smooth and even; free from oxide scale, foreign matter, and, in particular, free from lubricants. The test piece shall have a surface finish that will allow an accurate measurement of the diameter of the indentation.
Note: for indentations made with the smaller ball indenters, it might be necessary to polish or lap the surface of test piece.
6.2 Preparation shall be carried out in such a way that any alteration of the surface, for example, due to excessive heating or cold-working, is minimized.
6.3 The thickness of the test piece shall be at least eight times the depth of indentation. Values for the minimum thickness of the test piece in relation to the mean diameter of indentation are given in Annex A. After test, visible deformation at the back of the test piece can indicate that the test piece is too thin.
7 Test procedure
7.1 In general, the test shall be carried out at ambient temperature within the limits of 10℃~35℃. For the tests requiring strictly on temperature, the temperature is 23℃±5℃.
7.2 Prior to test, the state of hardness testing machine shall be verified according to Annex B.
7.3 The test forces given in Table 2 shall be used. Other test forces and force-diameter indices may also be used by special agreement.
Contents of GB/T 231.1-2018
Foreword i
1 Scope
2 Normative references
3 Principle
4 Symbols and definitions
5 Test apparatus
6 Test piece
7 Test procedure
8 Uncertainty of results
9 Test report
Annex A (Normative) Minimum thickness of the test piece in relation to the mean diameter of indentation
Annex B (Normative) Procedure for periodic checking of the hardness testing machine by the user
Annex C (Informative) Uncertainty of the measured hardness values
Bibliography
