ASTM E1450-09
(Test Method)Standard Test Method for Tension Testing of Structural Alloys in Liquid Helium
Standard Test Method for Tension Testing of Structural Alloys in Liquid Helium
SIGNIFICANCE AND USE
Tension tests provide information on the strength and ductility of materials under uniaxial tensile stresses. This information may be useful for alloy development, comparison and selection of materials, and quality control. Under certain circumstances, the information may also be useful for design.
The force-time and force-extension records for alloys tested in liquid helium using displacement control are serrated (1). Serrations are formed by repeated bursts of unstable plastic flow and arrests. The unstable plastic flow (discontinuous yielding) is a free-running process occurring in localized regions of the reduced section at higher than nominal rates of strain with internal specimen heating. Examples of serrated stress-strain curves for a typical austenitic stainless steel with discontinuous yielding are shown in Fig. 2.
A constant specimen temperature cannot be maintained at all times during tests in liquid helium. The specimen temperature at local regions in the reduced section rises temporarily above 4 K during each discontinuous yielding event (see Fig. 2), owing to adiabatic heat. The number of events and the magnitude of the associated drops in magnitude of force are a function of the material composition and other factors such as specimen size and test speed. Typically, altering the mechanical test variables can modify but not eliminate the discontinuous yielding (2-4). Therefore, tensile property measurements of alloys in liquid helium (especially tensile strength, elongation, and reduction of area) lack the usual significance of property measurements at room temperature where deformation is more nearly isothermal and discontinuous yielding typically does not occur.
The stress-strain response of a material tested in liquid helium depends on whether force control or displacement control is used (3). Crosshead displacement control is specified in this standard since the goal is material characterization by conventional methods. The possibility of a di...
SCOPE
1.1 This test method describes procedures for the tension testing of structural alloys in liquid helium. The format is similar to that of other ASTM tension test standards, but the contents include modifications for cryogenic testing which requires special apparatus, smaller specimens, and concern for serrated yielding, adiabatic heating, and strain-rate effects.
1.2 To conduct a tension test by this standard, the specimen in a cryostat is fully submerged in normal liquid helium (He I) and tested using crosshead displacement control at a nominal strain rate of 10−3 s−1 or less. Tests using force control or high strain rates are not considered.
1.3 This standard specifies methods for the measurement of yield strength, tensile strength, elongation, and reduction of area. The determination of the elastic modulus is treated in Test Method E 111.
Note 1—The boiling point of normal liquid helium (He I) at sea level is 4.2 K (−269°C or −452.1°F or 7.6°R). It decreases with geographic elevation and is 4.0 K (−269.2°C or −452.5°F or 7.2°R) at the National Institute of Standards and Technology in Colorado, 1677 m (5500 ft) above sea level. In this standard the temperature is designated 4 K.
1.4 Values stated in SI units are treated as primary. Values stated in U.S. customary units are treated as secondary.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. See Section 5.
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Designation: E1450 − 09
Standard Test Method for
1
Tension Testing of Structural Alloys in Liquid Helium
This standard is issued under the fixed designation E1450; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope E4Practices for Force Verification of Testing Machines
E6Terminology Relating to Methods of MechanicalTesting
1.1 This test method describes procedures for the tension
E8/E8MTest Methods for Tension Testing of Metallic Ma-
testing of structural alloys in liquid helium. The format is
terials
similar to that of other ASTM tension test standards, but the
E29Practice for Using Significant Digits in Test Data to
contents include modifications for cryogenic testing which
Determine Conformance with Specifications
requires special apparatus, smaller specimens, and concern for
E83Practice for Verification and Classification of Exten-
serrated yielding, adiabatic heating, and strain-rate effects.
someter Systems
1.2 To conduct a tension test by this standard, the specimen
E111Test Method for Young’s Modulus, Tangent Modulus,
in a cryostat is fully submerged in normal liquid helium (He I)
and Chord Modulus
and tested using crosshead displacement control at a nominal
E1012Practice for Verification of Testing Frame and Speci-
−3 −1
strain rate of 10 s or less. Tests using force control or high
men Alignment Under Tensile and Compressive Axial
strain rates are not considered.
Force Application
1.3 This standard specifies methods for the measurement of
3. Terminology
yield strength, tensile strength, elongation, and reduction of
3.1 Definitions:
area.ThedeterminationoftheelasticmodulusistreatedinTest
Method E111. 3.1.1 Thedefinitionsoftermsrelatingtotensiontestingthat
appear in Terminology E6 shall apply here. The definitions in
NOTE 1—The boiling point of normal liquid helium (He I) at sea level
this section also apply.
is 4.2 K (−269°C or −452.1°F or 7.6°R). It decreases with geographic
3.1.2 adiabatic heating—the internal heating of a specimen
elevation and is 4.0 K (−269.2°C or −452.5°F or 7.2°R) at the National
Institute of Standards and Technology in Colorado, 1677 m (5500 ft)
resulting from tension testing under conditions such that the
above sea level. In this standard the temperature is designated 4 K.
heat generated by plastic work cannot be quickly dissipated to
1.4 Values stated in SI units are treated as primary. Values the surrounding cryogen.
stated in U.S. customary units are treated as secondary.
3.1.3 adjusted length of the reduced section—the length of
1.5 This standard does not purport to address all of the the reduced section plus an amount calculated to compensate
safety concerns, if any, associated with its use. It is the for strain in the fillet region.
responsibility of the user of this standard to establish appro-
3.1.4 axial strain—the average of the longitudinal strains
priate safety and health practices and determine the applica-
measuredatoppositeorequallyspacedsurfacelocationsonthe
bility of regulatory limitations prior to use. See Section 5.
sidesofthelongitudinalaxisofsymmetryofthespecimen.The
longitudinal strains are measured using two or more strain-
2. Referenced Documents
sensing devices located at the mid-length of the reduced
2
2.1 ASTM Standards:
section.
A370Test Methods and Definitions for Mechanical Testing
3.1.5 bending strain—the difference between the strain at
of Steel Products
the surface of the specimen and the axial strain (the bending
strain varies around the circumference and along the reduced
section of the specimen).
1
This test method is under the jurisdiction of ASTM Committee E28 on
Mechanical Testing and is the direct responsibility of Subcommittee E28.04 on 3.1.6 Dewar—a vacuum-insulated container for cryogenic
Uniaxial Testing.
fluids.
Current edition approved June 1, 2009. Published August 2009. Originally
3.1.7 discontinuous yielding stress,σ—thepeakstressatthe
approved in 1992. Last previous edition approved in 2003 as E1450–03. DOI:
i
10.1520/E1450-09.
initiation of the first measurable serration on the curve of
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
stress-versus-strain.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3.1.7.1 Discussion—The parameter σ is a function of test
Standards volume information, refer to the standard’s Document Summary page on i
the ASTM website. variables and is not a material constant.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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E145
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This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:E1450–03 Designation: E 1450 – 09
Standard Test Method for
1
Tension Testing of Structural Alloys in Liquid Helium
This standard is issued under the fixed designation E1450; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method describes procedures for the tension testing of structural alloys in liquid helium. The format is similar to
that of other ASTM tension test standards, but the contents include modifications for cryogenic testing which requires special
apparatus, smaller specimens, and concern for serrated yielding, adiabatic heating, and strain-rate effects.
1.2 To conduct a tension test by this standard, the specimen in a cryostat is fully submerged in normal liquid helium (He I) and
−3 −1
testedusingcrossheaddisplacementcontrolatanominalstrainrateof10 s orless.Testsusingforcecontrolorhighstrainrates
are not considered.
1.3 This standard specifies methods for the measurement of yield strength, tensile strength, elongation, and reduction of area.
The determination of the elastic modulus is treated in Test Method E111.
NOTE 1—The boiling point of normal liquid helium (He I) at sea level is 4.2 K (−269°C or −452.1°F or 7.6°R). It decreases with geographic elevation
and is 4.0 K (−269.2°C or −452.5°F or 7.2°R) at the National Institute of Standards and Technology in Colorado, 1677 m (5500 ft) above sea level. In
this standard the temperature is designated 4 K.
1.4 Values stated in SI units are treated as primary. Values stated in U.S. customary units are treated as secondary.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use. See Section 5.
2. Referenced Documents
2
2.1 ASTM Standards:
A370 Test Methods and Definitions for Mechanical Testing of Steel Products
E4 Practices for Force Verification of Testing Machines
E6 Terminology Relating to Methods of Mechanical Testing
3
E8Test Methods for Tension Testing of Metallic Materials
3
E8MTest Methods for Tension Testing of Metallic Materials [Metric] 8/E8M Test Methods for Tension Testing of Metallic
Materials
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
3
E83 Practice for Verification and Classification of Extensometer System Systems
E 111 Test Method for Young’s Modulus, Tangent Modulus, and Chord Modulus
3
E1012 Practice for Verification of Specimen Alignment Under Tensile Loading Practice for Verification of Test Frame and
Specimen Alignment Under Tensile and Compressive Axial Force Application
3. Terminology
3.1 Definitions:
3.1.1 The definitions of terms relating to tension testing that appear inTerminology E6 shall apply here.The definitions in this
section also apply.
3.1.2 adiabatic heating—the internal heating of a specimen resulting from tension testing under conditions such that the heat
generated by plastic work cannot be quickly dissipated to the surrounding cryogen.
3.1.3 adjusted length of the reduced section—the length of the reduced section plus an amount calculated to compensate for
strain in the fillet region.
1
This test method is under the jurisdiction ofASTM Committee E28 on MechanicalTesting and is the direct responsibility of Subcommittee E28.04 on UniaxialTesting.
Current edition approved August 10, 2003. Published September 2003. Originally approved in 1992. Last previous edition approved in 1998 as E1459–92 (1998).
Current edition approved June 1, 2009. Published August 2009. Originally approved in 1992. Last previous edition approved in 2003 as E1459–03.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
, Vol 01.03.volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
E1450–09
3.1.4 axial strain—the average of the longitudinal strains measured at opposite or equally spaced surface locations on the sides
of the longitudinal axis of symm
...
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