1 Scope
This standard specifies the method for the uninterrupted and interrupted creep testing and defines the properties of metallic materials which can be determined from these tests, in particular the creep elongation and the time of creep rupture, at a specified temperature.
The stress rupture test is also covered by this standard, as is the test of smooth test pieces and notched test pieces.
Note: in stress rupture test, elongation is not generally recorded during the test, only the time to failure under a given load, or to note that a predetermined time was exceeded under a given force.
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 1800.2 Geometrical Product Specifications (GPS) - Limits and Fits - Part 2: Tables of Standard Tolerance Grades and Limit Deviations for Holes and Shafts (GB/T 1800.2-2009, ISO 286-2:1988, MOD)
GB/T 2975 Steel and Steel Products - Location and Preparation of Test Pieces for Mechanical Testing (GB/T 2975-1998, eqv ISO 377:1997)
GB/T 4338 Metallic Materials- Tensile Testing at Elevated Temperature (GB/T 4338-2006, ISO 783:1999, MOD)
GB/T 4989 Extension and Compensating Cables for Thermocouples (GB/T 4989-1994, eqv IEC 584-3:1989)
GB/T 8170 Rules of Rounding Off for Numerical Values & Expression and Judgment of Limiting Values
GB/T 10623 Metallic Material - Mechanical Testing - Vocabulary (GB/T 10623-2008, ISO 23718:2007, MOD)
GB/T 12160 Calibration of Extensometers Used in Uniaxial Testing (GB/T 12160-2002, ISO 9513:1999, IDT)
GB/T 16825.2 Verification of Static Uniaxial Testing Machines - Part 2: Tension Creep Testing Machines - Verification of the Applied Force (GB/T 16825.2-2005, ISO 7500-2:1996, MOD)
GB/T 16839.1 Thermocouple - Part 1: Reference Tables (GB/T 16839.1-1997, idt IEC 60584-1:1995)
GB/T 16839.2 Thermocouple - Part 2: Tolerance (GB/T 16839.2-1997, idt IEC 60584-2:1982)
JJG 141 Working Noble Metal Thermocouples
JJG 276 Verification Regulation of High-temperature Creep and Stress-rupture Testing Machines
JJG 351 Verification Regulation of Working Base Metal Thermocouple
JJG 617 Verification Regulation of Digital Temperature Indicators and Controllers
ASTM E1012-05 Standard Practice for Verification of Test Frame and Specimen Alignment Under Tensile and Compressive Axial Force Application
3 Terms and Definitions
For the purposes of this document, the following terms and definitions specified in GB/T 10623 apply.
Note: several different gauge lengths and reference lengths are specified in this standard. These lengths reflect custom and practice used in different laboratories. In some cases, the lengths are physically marked on the test piece as lines or ridges; in other cases, the length may be a virtual length based upon calculations to determine an appropriate length to be used for the determination of creep elongation. For some test pieces, Lr, Lo and Le are the same length (see 3.1, 3.2 and 3.5).
3.1
Reference length
Lr
Base length used for the calculation of elongation
Note: a method to calculate this value is given in 7.5 for test pieces where the extensometer is attached to either ridges on the parallel length or to the shoulders of the test piece.
3.1.1
Original reference length
Lro
Reference length determined at ambient temperature before the test
Note: In general, Lro≥5D.
Foreword I
1 Scope
2 Normative References
3 Terms and Definitions
4 Symbols and Designations
5 Principle
6 Apparatus
7 Test Pieces
8 Test Procedure
9 Determination of Results
10 Test Validity
11 Accuracy of Results
12 Test Report
Appendix A (Informative) Information Concerning Different Types of Thermocouples
Appendix B (Informative) Calibration Methods of Thermocouples
Appendix C (Normative) Creep Testing Using Test Pieces with V or Blunt Circumferential Notches
Appendix D (Informative) Method of Estimating the Uncertainty of the Measurement in Accordance with the Guide to the Expression of Uncertainty in Measurement (GUM)
Appendix E (Informative) Representation of Results and Graphical Extrapolation
