ASTM E139-00

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 139 – 00
Standard Test Methods for
Conducting Creep, Creep-Rupture, and Stress-Rupture
Tests of Metallic Materials
This standard is issued under the fixed designation E 139; 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 (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 2. Referenced Documents
1.1 These test methods cover the determination of the 2.1 ASTM Standards:
amount of deformation as a function of time (creep test) and E 4 Practices for Force Verification of Testing Machines
the measurement of the time for fracture to occur when E 6 Terminology Relating to Methods of Mechanical Test-
sufficient force is present (rupture test) for materials when ing
under constant tensile forces at constant temperature. It also E 8 Test Methods for Tension Testing of Metallic Materials
includes the essential requirements for testing equipment. For E 21 Test Methods for Elevated Temperature Tension Tests
information of assistance in determining the desirable number of Metallic Materials
and duration of tests, reference should be made to Section 9. E 29 Practice for Using Significant Digits in Test Data to
1.2 These test methods list the information which should be Determine Conformance with Specifications
included in reports of tests. The intention is to ensure that all E 74 Practice for Calibration of Force-Measuring Instru-
useful and readily available information is transmitted to ments for Verifying the Force Indication of Testing Ma-
interested parties. Reports receive special attention for the chines
following reasons: (1) results from different, recognized pro- E 83 Practice for Verification and Classification of Exten-
cedures vary significantly; therefore, identification of methods someters
used is important; ( 2) later studies to establish important E 177 Practice for Use of the Terms Precision and Bias in
variables are often hampered by the lack of detailed informa- ASTM Test Methods
tion in published reports; ( 3) the nature of prolonged tests E 220 Method for Calibration of Thermocouples by Com-
often makes retest impractical, and at the same time makes it parison Techniques
difficult to remain within the recommended variations of some E 292 Practice for Conducting Time-for-Rupture Notch
controlled variables. A detailed report permits transmittal of Tension Tests of Materials
test results without implying a degree of control which was not E 633 Guide for Use of Thermocouples in Creep and Stress
achieved. Rupture Testing to 1800°F (1000°C) in Air
1.3 Tests on notched specimens are not included. These tests E 1012 Practice for Verification of Specimen Alignment
are addressed in Practice E 292. Under Tensile Loading
1.4 Tests under conditions of short times are not included. 2.2 Military Standard:
These test methods are addressed in Test Methods E 21. MIL-STD-120 Gage Inspection
1.5 The values stated in inch-pound units are to be regarded 2.3 ASTM Adjuncts:
as the standard. Standard unmachined specimens for calibrating creep testing
1.6 This standard does not purport to address all of the machines (4 by ⁄16 in. square bar)
safety concerns, if any, associated with its use. It is the
3. Terminology
responsibility of the user of this standard to establish appro-
3.1 Definitions—The definitions of terms relating to creep
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. testing, which appear in Section E of Terminology E 6 shall
apply to the terms used in this practice. For the purpose of this
This practice is under the jurisdiction of the ASTM Committee E-28 on
Annual Book of ASTM Standards, Vol 03.01.
Mechanical Testing and is the direct responsibility of Subcommittee E28.10 on
Annual Book of ASTM Standards, Vol 14.02.
Effect of Elevated Temperature on Properties.
Annual Book of ASTM Standards, Vol 14.03.
Current edition approved May 10, 2000. Published August 2000. Originally
Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700
published as E 139 – 58. Last previous edition E 139 – 96.
Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Available from ASTM Headquarters. Order Adjunct: ADJE0139.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E 139
practice only, some of the more general terms are used with the ability which best defines the service usefulness of the mate-
restricted meanings given below. rial.
3.2 Definitions of Terms Specific to This Standard:
5. Apparatus
3.2.1 axial strain—the average of the strain measured on
5.1 Testing Machine:
opposite sides and equally distant from the specimen axis.
5.1.1 The accuracy of the testing machine shall be within
3.2.2 bending strain— the difference between the strain at
the permissible variation specified in Practices E 4.
the surface of the specimen and the axial strain. In general it
5.1.2 Exercise precaution to ensure that the force on the
varies from point to point around and along the reduced section
specimens is applied as axially as possible. Perfect axial
of the specimen.
alignment is difficult to obtain, especially when the pull rods
3.2.2.1 maximum bending strain—measured at a position
and extensometer rods pass through packing at the ends of the
along the length of the reduced section of a straight unnotched
furnace. However, the machine and grips should be capable of
specimen.
loading a precisely made specimen so that the maximum
3.2.3 creep—the time-dependent strain that occurs after the
bending strain does not exceed 10 % of the axial strain, when
application of a load which is thereafter maintained constant.
the calculations are based on strain readings taken at zero force
3.2.4 creep-rupture test—a test in which progressive speci-
and at the lowest force for which the machine is being
men deformation and the time for rupture are measured. In
qualified.
general, deformation is much larger than that developed during
a creep test.
NOTE 1—This requirement is intended to limit the maximum contribu-
3.2.5 creep test—a test that has the objective of measuring
tion of the testing apparatus to the bending which occurs during a test. It
is recognized that even with qualified apparatus, different tests may have
creep and creep rates occurring at stresses usually well below
quite different percent bending strains due to chance orientation of a
those which would result in fracture during the time of testing.
loosely fitted specimen, lack of symmetry of that particular specimen,
Since the maximum deformation is only a few percent, a
lateral force from furnace packing, and thermocouple wire, etc.
sensitive extensometer is required.
5.1.2.1 In testing of brittle material, even a bending strain of
3.2.6 gage length—the original distance between gage
10 % may result in lower strength than would be obtained with
marks made on the specimen for determining elongation after
improved axiality. In these cases, measurements of bending
fracture.
strain on the specimen to be tested may be specifically
3.2.7 length of the reduced section—the distance between
requested and the permissible magnitude limited to a smaller
tangent points of the fillets which bound the reduced section.
value.
3.2.7.1 The adjusted length of the reduced section is greater
5.1.2.2 The testing apparatus may be qualified by measure-
than the length of the reduced section by an amount calculated
ments of axiality made at room temperature. When one is
to compensate for strain in the fillet region (see 9.2.3).
making an evaluation of equipment, the specimen form should
3.2.8 plastic strain during loading—the portion of the strain
be the same as that used during the elevated-temperature tests.
during loading determined as the offset from the linear portion
The specimen concentricity should be as near perfect as
to the end of a stress-strain curve made during load application.
reasonably possible. Only elastic strains should occur through-
The offset construction is shown in Test Methods E 8.
out the reduced section. This requirement may necessitate use
3.2.9 reduced section, of the specimen—the central portion
of a material different from that used during the elevated-
of the length having a cross section smaller than the ends which
temperature test.
are gripped. The cross section is uniform within tolerances
5.1.2.3 Test Method E 1012, or an equivalent test method
prescribed in 7.6.
(1,2), shall be used for the measurement and calculation of
3.2.10 strain during loading—the change in strain during
bending strain for round, rectangular, and thin strip specimens.
the time interval from the start of loading to the instant of
5.1.2.4 Axiality measurements should be made at room
full-load application.
temperature on the assembled machine, pull rods, and grips
3.2.11 stress-rupture test—a test in which time for rupture is
before use for testing. Gripping devices and pull rods may
measured, no deformation measurements being made during
oxidize, warp, and creep with repeated use at elevated tem-
the test.
peratures. Increased bending stresses may result. Therefore,
3.2.12 total plastic strain, at a specified time— equal to the
grips and pull rods should be periodically retested for axiality
sum of plastic strain during loading plus creep.
and reworked when necessary.
3.2.13 total strain, at a specified time—equal to the sum of
5.1.3 The testing machine should incorporate means of
the strain during loading plus creep.
taking up the extension of the specimen so that the load will be
maintained within the limits specified in 5.1.1. The extension
4. Significance and Use
of the specimen should not allow the loading system to
4.1 Rupture tests, properly interpreted, provide a measure of
introduce eccentricity of loading in excess of the limits
the ultimate load-carrying ability of a material as a function of
specified in 5.1.2. The take-up mechanism should avoid
time. Creep tests measure the load-carrying ability for limited
introducing shock loads, overloading due to friction or inertia
deformations. The two tests supplement each other in defining
in the loading system, or apply torque to the specimen.
the load-carrying ability of a material. In selecting material and
designing parts for service at elevated temperatures, the type of
test data used will depend on the criterion of load-carrying The boldface numbers refer to the References at the end of this standard.
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E 139
5.1.4 The testing machine should be erected to secure due to contamination, etc., and should be annealed periodically
reasonable freedom from vibration and shock due to external and checked for calibration. Care should be exercised to keep
causes. Precautions should be made to minimize the transmis- the thermocouples clean prior to exposure and during use at
sion of shock to neighboring test machines and specimens elevated temperatures.
when a specimen fractures.
5.3.3.2 Measurement of the drift in calibration of thermo-
5.1.5 For high-temperature testing of materials which are
couples during use is difficult. When drift is a problem during
readily attacked by their environment (such as oxidation of
tests, a method should be devised to check the readings of the
metal in air), the specimen may be enclosed in a capsule so that
thermocouples on the specimens during the test. For reliable
it can be tested in a vacuum or inert-gas atmosphere. When
calibration of thermocouples after use, the temperature gradi-
such equipment is used, the necessary corrections to obtain true
ent of the testing furnace must be reproduced during the
specimen loads must be made. For instance, compensation
recalibration.
must be made for differences in pressures inside and outside of
5.3.4 Temperature-measuring, controlling and recording in-
the capsule and for any load variation due to sealing-ring
struments should be calibrated periodically against a secondary
friction, bellows or other features.
standard, such as a precision potentiometer. Lead-wire error
5.2 Heating Apparatus:
should be checked with the lead wires in place as they normally
5.2.1 The apparatus for and method of heating the speci-
are used.
mens should provide the temperature control necessary to
5.4 Extensometer System:
satisfy the requirements specified in 9.4.4 without manual
5.4.1 The sensitivity and accuracy of the strain-measuring
adjustments more frequent than once in each 24-h period after
equipment should be suitable to define the creep characteristics
load application.
with the precision required for the application of the data. The
5.2.2 Heating shall be by an electric resistance or radiation
sensitivity and accuracy of the extensometer should be made
furnace with the specimen in air at atmospheric pressure unless
part of the report of test results.
other media are specifically agreed upon in advance.
5.4.2 Nonaxiality of loading is usually sufficient to cause
significant errors at small strains when strain is measured on
NOTE 2—The media in which the specimens are tested may have a
considerable effect on the results of tests. This is particularly true when the only one side of the specimen (4). Therefore, the extensometer
properties are influenced by oxidation or corrosion during the test,
should be attached to and indicate strain on opposite sides of
although other effects can also influence test results.
the specimen. The reported strain should be the average of the
5.3 Temperature-Measuring Apparatus (3) :
strains on the two sides, either a mechanical or electrical
5.3.1 The method of temperature measurement must be
average internal to the instrument or a numerical average of
sufficiently sensitive and reliable to ensure that the temperature
two separate readings.
of the specimen is within the limits specified in 9.4.4.
5.4.3 Whenever possible the extensometer should be at-
5.3.2 Temperature should be measured with thermocouples
tached to the specimen, not to any load carrying parts joined to
in conjunction with potentiometers or millivoltmeters.
the specimen, because the intervening joints and parts intro-
duce
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