ASTM E1450-16
(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
4.1 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.
4.2 The force-time and force-extension records for some alloys tested in liquid helium using displacement control are often serrated (1).3 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.
4.3 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 heating. 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.
4.4 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 convention...
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 tensile cryostat is fully submerged in normal liquid helium (He I) and tested using crosshead displacement control at a nominal strain rate of 10−3 mm/mm/s 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 Young’s 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.
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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E1450 − 16
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
E177Practice for Use of the Terms Precision and Bias in
inatensilecryostatisfullysubmergedinnormalliquidhelium
ASTM Test Methods
(He I) and tested using crosshead displacement control at a
−3 E691Practice for Conducting an Interlaboratory Study to
nominal strain rate of 10 mm/mm/s or less.Tests using force
Determine the Precision of a Test Method
control or high strain rates are not considered.
E111Test Method for Young’s Modulus, Tangent Modulus,
1.3 This standard specifies methods for the measurement of
and Chord Modulus
yield strength, tensile strength, elongation, and reduction of
E1012Practice for Verification of Testing Frame and Speci-
area. The determination of the Young’s modulus is treated in
men Alignment Under Tensile and Compressive Axial
Test Method E111.
Force Application
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
3. Terminology
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)
3.1 Definitions of Terms Common to Mechanical Testing—
above sea level. In this standard the temperature is designated 4 K.
3.1.1 The definitions of mechanical testing terms that ap-
1.4 Values stated in SI units are treated as primary. Values
pear in the Terminology E6 apply to this test method. These
stated in U.S. customary units are treated as secondary.
terms include bending strain, elongation, extensometer, force,
1.5 This standard does not purport to address all of the gauge length, proportional limit, reduced section, reduction of
safety concerns, if any, associated with its use. It is the
area,stress-straindiagram,tensilestrength,andYoung’smodu-
responsibility of the user of this standard to establish appro-
lus.
priate safety and health practices and determine the applica-
3.1.2 In addition, the following common terms fromTermi-
bility of regulatory limitations prior to use. See Section 5.
nology E6 are defined:
3.1.3 adjusted length of the reduced section—the length of
2. Referenced Documents
the reduced section plus an amount calculated to compensate
2
2.1 ASTM Standards:
for strain in the fillet region.
A370Test Methods and Definitions for Mechanical Testing
3.1.4 discontinuous yielding, n—in a uniaxial test, a hesita-
of Steel Products
tion or fluctuation of force observed at the onset of plastic
deformation, due to localized yielding.
1
This test method is under the jurisdiction of ASTM Committee E28 on
3.1.4.1 Discussion—The stress-strain curve need not appear
Mechanical Testing and is the direct responsibility of Subcommittee E28.04 on
to be discontinuous.
Uniaxial Testing.
Current edition approved Nov. 15, 2016. Published February 2017. Originally
3.1.5 discontinuous yielding stress,σ—thepeakstressatthe
i
approved in 1992. Last previous edition approved in 2009 as E1450–09. DOI:
initiation of the first measurable serration on the curve of
10.1520/E1450-16.
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
3.1.5.1 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 Conshohocke
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM 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 − 09 E1450 − 16
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. A number 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 tensile cryostat is fully submerged in normal liquid helium (He
−3 −1
I) and tested using crosshead displacement control at a nominal strain rate of 10 smm/mm/s 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 elasticYoung’s 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
E8/E8M Test Methods for Tension Testing of Metallic Materials
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E83 Practice for Verification and Classification of Extensometer Systems
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E111 Test Method for Young’s Modulus, Tangent Modulus, and Chord Modulus
E1012 Practice for Verification of Testing Frame and Specimen Alignment Under Tensile and Compressive Axial Force
Application
3. Terminology
3.1 Definitions:Definitions of Terms Common to Mechanical Testing—
3.1.1 The definitions of terms relating to tension testing mechanical testing terms that appear in the Terminology E6 shall apply
here. The definitions in this section also apply.apply to this test method. These terms include bending strain, elongation,
extensometer, force, gauge length, proportional limit, reduced section, reduction of area, stress-strain diagram, tensile strength, and
Young’s modulus.
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 Uniaxial Testing.
Current edition approved June 1, 2009Nov. 15, 2016. Published August 2009February 2017. Originally approved in 1992. Last previous edition approved in 20032009
as E1450 – 03.E1450 – 09. DOI: 10.1520/E1450-09.10.1520/E1450-16.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
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
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E1450 − 16
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.
3.1.2 In addition, the following common terms from Terminology E6 are defined:
3
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