Metallic materials—Tensile testing—Part 1: Method of test at room temperature
1 Scope
This document specifies the definition, symbols and interpretations, principle, test pieces and its dimension measurement, testing equipment, test requirements, property measurement, rounding off of measurement results and test report for tensile testing of metallic materials.
This document is applicable to the determination for tensile properties of metallic materials at room temperature.
Note: Annex C gives further recommendations for computer-controlled testing machines.
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 2975 Steel and steel products—Location and preparation of samples and test pieces for mechanical testing (GB/T 2975-2018, ISO 377: 2017, MOD)
GB/T 8170 Rules of rounding off for numerical values & expression and judgment of limiting values
GB/T 10623 Metallic materials—Test pieces for tensile testing (GB/T 10623-2008, ISO 23718: 2007, MOD)
GB/T 12160 Metallic materials—Calibration of extensometers systems used in uniaxial testing (GB/T 12160-2019, ISO 9513: 2012, IDT)
GB/T 16825.1 Verification of static uniaxial testing machines—Part 1: Tension/ compression testing machines—Verification and calibration of the force measuring system (GB/T 16825.1-2008, ISO 7500-1: 2004, IDT)
GB/T 22066 Evaluation for computerized data acquisition systems for used in static uniaxial testing machines
JJG 139 Tension, compression and universal testing machines
JJG 475 Verification Regulation of Electronic Universal Testing Machine
JJG 762 Verification Regulation for Extensometer
JJG 1063 Verification Regulation of Electro-hydraulic Servo Universal Testing Machines
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 10623 as well as the following apply.
3.1
gauge length
L
length of the parallel portion of the test piece on which elongation is measured at any moment during the test
Note: See reference [6] in the Bibliography.
3.1.1
original gauge length
Lo
length between gauge length (3.1) marks on the test piece measured at room temperature before the test
Note: See reference [6] in the Bibliography.
3.1.2
final gauge length after fracture
Lu
length between gauge length (3.1) marks on the test piece measured after rupture, at room temperature, the two pieces having been carefully fitted back together so that their axes lie in a straight line
Note: See reference [6] in the Bibliography.
3.2
parallel length
Lc
length of the parallel reduced section of the test piece
Note: The concept of parallel length is replaced by the concept of distance between grips for unmachined test pieces. See No. [6] in Bibliography.
3.3
elongation
increase in the original gauge length (3.1.1) at any moment during the test
Note: See reference [6] in the Bibliography.
3.4
percentage elongation
elongation (3.3) expressed as a percentage (%) of the original gauge length(Lo) (3.1.1)
Note: See reference [6] in the Bibliography.
3.4.1
percentage permanent elongation
increase in the original gauge length (Lo) (3.1.1) of a test piece after removal of a specified stress, expressed as a percentage (%) of the original gauge length
Note: See reference [6] in the Bibliography.
3.4.2
percentage elongation after fracture
A
permanent elongation (3.3) of the gauge length after fracture (Lu–Lo), expressed as a percentage (%) of the original gauge length (Lo) (3.1.1)
Note: For further information, see 8.1 and reference [6] in the Bibliography.
3.5
extensometer gauge length
Le
initial gauge length of the extensometer used for measurement of extension (3.6)
Note 1: For the determination of several properties which are based (partly or complete) on extension, e.g. Rp, Ae or Ag, the use of an extensometer is mandatory.
Note 2: For further information, see 8.3 and reference [6] in the Bibliography.
3.6
extension
increase in the extensometer gauge length (Le) (3.5), at any moment during the test
Note: See reference [6] in the Bibliography.
3.6.1
percentage extension
strain
e
extension (3.6) expressed as a percentage of the extensometer gauge length (Le) (3.5)
Note: e is commonly called engineering strain.
3.6.2
percentage permanent extension
increase in the extensometer gauge length (3.5), after removal of a specified stress (3.10) from the test piece, expressed as a percentage (%) of the extensometer gauge length (Le)
Note: See reference [6] in the Bibliography.
3.6.3
percentage yield point extension
Ae
< discontinuous yielding materials > extension (3.6) between the start of yielding and the start of uniform work-hardening, expressed as a percentage (%) of the extensometer gauge length Le (3.5)
Note: See Figure 7 and reference [6] in the Bibliography.
3.6.4
percentage total extension at maximum force
Agt
total extension (3.6) (elastic extension plus plastic extension) at maximum force, expressed as a percentage (%) of the extensometer gauge length (Le) (3.5)
Note: see Figure 1.
3.6.5
percentage plastic extension at maximum force
Ag
plastic extension (3.6) at maximum force, expressed as a percentage (%) of the extensometer gauge length (Le) (3.5)
Note: see Figure 1.
Key:
A——percentage elongation after fracture (determined from the extensometer signal or directly from the test piece, see 20.1);
Ag——percentage plastic extension at maximum force;
Agt——percentage total extension at maximum force;
At——percentage total extension at fracture;
e——percentage extension;
mE——slope of the elastic part of the stress-percentage extension curve;
R——stress;
Rm——tensile strength;
Δe——plateau extent (for determination of Ag, see Clause 17, for determination of Agt, see Clause 18).
Figure 1 Definition of extension
Contents
Foreword i
Introduction iv
1 Scope
2 Normative references
3 Terms and definitions
4 Symbols and interpretations
5 Principle
6 Test pieces
7 Determination of original cross-sectional area
8 Original gauge length and extensometer gauge length
9 Accuracy of testing equipment
10 Test requirements
11 Determination of the upper yield strength
12 Determination of the lower yield strength
13 Determination of proof strength at plastic extension
14 Determination of proof strength at total extension
15 Method of verification of permanent set strength
16 Determination of the percentage yield point extension
17 Determination of the percentage plastic extension at maximum force
18 Determination of the percentage total extension at maximum force
19 Determination of the percentage total extension at fracture
20 Determination of the percentage elongation after fracture
21 Determination of the percentage reduction of area
22 Rounding of test results
23 Test report
24 Measurement uncertainty
Annex A (Informative) Comparison of structure changes between this document and ISO 6892-1:
Annex B (Informative) Technical differences between this document and ISO 6892-1: 2019 and their reasons
Annex C (Informative) Recommendations concerning the use of computer-controlled tensile testing machines
Annex D (Nominative) Determination of the modulus of elasticity of metallic materials using a uniaxial tensile test
Annex E (Normative) Types of test pieces to be used for thin products: sheets and strips between 0.1 mm and < 3 mm thick
Annex F (Normative) Types of test pieces to be used for wire, bars, and sections with a diameter or thickness less than 4 mm
Annex G (normative) Types of test pieces to be used for sheets and flats of thickness equal to or greater than 3 mm and wire, bars, and sections of diameter or thickness equal to or greater than 4 mm
Annex H (Normative) Types of test pieces to be used for tubes
Annex I (Informative) Estimation of the compensating crosshead separation rate in consideration of the deformation of the testing machine
Annex J (Informative) Determination of proof strength at plastic extension (Rp) by successive approximation method
Annex K (Informative) Determination of permanent set strength (Rr0.2) by stress relaxation method
Annex L (Informative) Determination of the percentage plastic elongation without necking (Awn) for long products such as bars, wire, and rods
Annex M (Informative) Measuring the percentage elongation after fracture if the specified value is less than 5%
Annex N (Informative) Determination of percentage elongation after fracture by position transferring method
Annex O (Informative) Estimation of the uncertainty of measurement
Annex P (Informative) Precision of tensile testing — Results from interlaboratory programmes
Bibliography
Metallic materials—Tensile testing—Part 1: Method of test at room temperature
1 Scope
This document specifies the definition, symbols and interpretations, principle, test pieces and its dimension measurement, testing equipment, test requirements, property measurement, rounding off of measurement results and test report for tensile testing of metallic materials.
This document is applicable to the determination for tensile properties of metallic materials at room temperature.
Note: Annex C gives further recommendations for computer-controlled testing machines.
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 2975 Steel and steel products—Location and preparation of samples and test pieces for mechanical testing (GB/T 2975-2018, ISO 377: 2017, MOD)
GB/T 8170 Rules of rounding off for numerical values & expression and judgment of limiting values
GB/T 10623 Metallic materials—Test pieces for tensile testing (GB/T 10623-2008, ISO 23718: 2007, MOD)
GB/T 12160 Metallic materials—Calibration of extensometers systems used in uniaxial testing (GB/T 12160-2019, ISO 9513: 2012, IDT)
GB/T 16825.1 Verification of static uniaxial testing machines—Part 1: Tension/ compression testing machines—Verification and calibration of the force measuring system (GB/T 16825.1-2008, ISO 7500-1: 2004, IDT)
GB/T 22066 Evaluation for computerized data acquisition systems for used in static uniaxial testing machines
JJG 139 Tension, compression and universal testing machines
JJG 475 Verification Regulation of Electronic Universal Testing Machine
JJG 762 Verification Regulation for Extensometer
JJG 1063 Verification Regulation of Electro-hydraulic Servo Universal Testing Machines
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 10623 as well as the following apply.
3.1
gauge length
L
length of the parallel portion of the test piece on which elongation is measured at any moment during the test
Note: See reference [6] in the Bibliography.
3.1.1
original gauge length
Lo
length between gauge length (3.1) marks on the test piece measured at room temperature before the test
Note: See reference [6] in the Bibliography.
3.1.2
final gauge length after fracture
Lu
length between gauge length (3.1) marks on the test piece measured after rupture, at room temperature, the two pieces having been carefully fitted back together so that their axes lie in a straight line
Note: See reference [6] in the Bibliography.
3.2
parallel length
Lc
length of the parallel reduced section of the test piece
Note: The concept of parallel length is replaced by the concept of distance between grips for unmachined test pieces. See No. [6] in Bibliography.
3.3
elongation
increase in the original gauge length (3.1.1) at any moment during the test
Note: See reference [6] in the Bibliography.
3.4
percentage elongation
elongation (3.3) expressed as a percentage (%) of the original gauge length(Lo) (3.1.1)
Note: See reference [6] in the Bibliography.
3.4.1
percentage permanent elongation
increase in the original gauge length (Lo) (3.1.1) of a test piece after removal of a specified stress, expressed as a percentage (%) of the original gauge length
Note: See reference [6] in the Bibliography.
3.4.2
percentage elongation after fracture
A
permanent elongation (3.3) of the gauge length after fracture (Lu–Lo), expressed as a percentage (%) of the original gauge length (Lo) (3.1.1)
Note: For further information, see 8.1 and reference [6] in the Bibliography.
3.5
extensometer gauge length
Le
initial gauge length of the extensometer used for measurement of extension (3.6)
Note 1: For the determination of several properties which are based (partly or complete) on extension, e.g. Rp, Ae or Ag, the use of an extensometer is mandatory.
Note 2: For further information, see 8.3 and reference [6] in the Bibliography.
3.6
extension
increase in the extensometer gauge length (Le) (3.5), at any moment during the test
Note: See reference [6] in the Bibliography.
3.6.1
percentage extension
strain
e
extension (3.6) expressed as a percentage of the extensometer gauge length (Le) (3.5)
Note: e is commonly called engineering strain.
3.6.2
percentage permanent extension
increase in the extensometer gauge length (3.5), after removal of a specified stress (3.10) from the test piece, expressed as a percentage (%) of the extensometer gauge length (Le)
Note: See reference [6] in the Bibliography.
3.6.3
percentage yield point extension
Ae
< discontinuous yielding materials > extension (3.6) between the start of yielding and the start of uniform work-hardening, expressed as a percentage (%) of the extensometer gauge length Le (3.5)
Note: See Figure 7 and reference [6] in the Bibliography.
3.6.4
percentage total extension at maximum force
Agt
total extension (3.6) (elastic extension plus plastic extension) at maximum force, expressed as a percentage (%) of the extensometer gauge length (Le) (3.5)
Note: see Figure 1.
3.6.5
percentage plastic extension at maximum force
Ag
plastic extension (3.6) at maximum force, expressed as a percentage (%) of the extensometer gauge length (Le) (3.5)
Note: see Figure 1.
Key:
A——percentage elongation after fracture (determined from the extensometer signal or directly from the test piece, see 20.1);
Ag——percentage plastic extension at maximum force;
Agt——percentage total extension at maximum force;
At——percentage total extension at fracture;
e——percentage extension;
mE——slope of the elastic part of the stress-percentage extension curve;
R——stress;
Rm——tensile strength;
Δe——plateau extent (for determination of Ag, see Clause 17, for determination of Agt, see Clause 18).
Figure 1 Definition of extension
Contents of GB/T 228.1-2021
Contents
Foreword i
Introduction iv
1 Scope
2 Normative references
3 Terms and definitions
4 Symbols and interpretations
5 Principle
6 Test pieces
7 Determination of original cross-sectional area
8 Original gauge length and extensometer gauge length
9 Accuracy of testing equipment
10 Test requirements
11 Determination of the upper yield strength
12 Determination of the lower yield strength
13 Determination of proof strength at plastic extension
14 Determination of proof strength at total extension
15 Method of verification of permanent set strength
16 Determination of the percentage yield point extension
17 Determination of the percentage plastic extension at maximum force
18 Determination of the percentage total extension at maximum force
19 Determination of the percentage total extension at fracture
20 Determination of the percentage elongation after fracture
21 Determination of the percentage reduction of area
22 Rounding of test results
23 Test report
24 Measurement uncertainty
Annex A (Informative) Comparison of structure changes between this document and ISO 6892-1:
Annex B (Informative) Technical differences between this document and ISO 6892-1: 2019 and their reasons
Annex C (Informative) Recommendations concerning the use of computer-controlled tensile testing machines
Annex D (Nominative) Determination of the modulus of elasticity of metallic materials using a uniaxial tensile test
Annex E (Normative) Types of test pieces to be used for thin products: sheets and strips between 0.1 mm and < 3 mm thick
Annex F (Normative) Types of test pieces to be used for wire, bars, and sections with a diameter or thickness less than 4 mm
Annex G (normative) Types of test pieces to be used for sheets and flats of thickness equal to or greater than 3 mm and wire, bars, and sections of diameter or thickness equal to or greater than 4 mm
Annex H (Normative) Types of test pieces to be used for tubes
Annex I (Informative) Estimation of the compensating crosshead separation rate in consideration of the deformation of the testing machine
Annex J (Informative) Determination of proof strength at plastic extension (Rp) by successive approximation method
Annex K (Informative) Determination of permanent set strength (Rr0.2) by stress relaxation method
Annex L (Informative) Determination of the percentage plastic elongation without necking (Awn) for long products such as bars, wire, and rods
Annex M (Informative) Measuring the percentage elongation after fracture if the specified value is less than 5%
Annex N (Informative) Determination of percentage elongation after fracture by position transferring method
Annex O (Informative) Estimation of the uncertainty of measurement
Annex P (Informative) Precision of tensile testing — Results from interlaboratory programmes
Bibliography
