ASTM E292-83(1996)e1
(Test Method)Standard Test Methods for Conducting Time-for-Rupture Notch Tension Tests of Materials
Standard Test Methods for Conducting Time-for-Rupture Notch Tension Tests of Materials
SCOPE
1.1 These test methods cover the determination of the time for rupture of notched specimens under conditions of constant load and temperature. These test methods also includes the essential requirements for testing equipment.
1.2 The values stated in inch-pound units are to be regarded as the standard. The units in parentheses are for information only.
1.3 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.
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e1
Designation: E 292 – 83 (Reapproved 1996) An American National Standard
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Methods for
Conducting Time-for-Rupture Notch Tension Tests of
Materials
This standard is issued under the fixed designation E 292; 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.
e NOTE—Editorial changes were made throughout in November 1996.
1. Scope MIL-STD-120 Gage Inspection
1.1 These test methods cover the determination of the time
3. Terminology
for rupture of notched specimens under conditions of constant
3.1 Definitions—The definitions of terms relating to creep
load and temperature. These test methods also includes the
testing, which appear in Section E of Terminology E 6 shall
essential requirements for testing equipment.
apply to the terms used in these test methods. For the purpose
1.2 The values stated in inch-pound units are to be regarded
of this practice only, some of the more general terms are used
as the standard. The units in parentheses are for information
with the restricted meanings given below.
only.
3.2 Definitions of Terms Specific to This Standard:
1.3 This standard does not purport to address all of the
3.2.1 axial strain—the average of the strain measured on
safety concerns, if any, associated with its use. It is the
opposite sides and equally distant from the specimen axis.
responsibility of the user of this standard to establish appro-
3.2.2 bending strain—the difference between the strain at
priate safety and health practices and determine the applica-
the surface of the specimen and the axial strain. In general, it
bility of regulatory limitations prior to use.
varies from point to point around and along reduced section of
2. Referenced Documents the specimen.
3.2.3 gage length—the original distance between gage
2.1 ASTM Standards:
marks made on the specimen for determining elongation after
A 453/A453M Specification for High-Temperature Bolting
fracture.
Materials, with Expansion Coefficients Comparable to
3.2.4 length of the reduced section—the distance between
Austenitic Steels
tangent points of the fillets that bound the reduced section.
E 4 Practices for Force Verification of Testing Machines
3.2.5 The adjusted length of the reduced section is greater
E 6 Terminology Relating to Methods of Mechanical Test-
than the length of the reduced section by an amount calculated
ing
to compensate for the strain in the fillets adjacent to the
E 8 Test Methods for Tension Testing of Metallic Materials
reduced section.
E 74 Practice of Calibration of Force-Measuring Instru-
3.2.6 maximum bending strain—the largest value of bend-
ments for Verifying the Force Indication of Testing Ma-
ing strain in the reduced section of the specimen. It can be
chines
calculated from measurements of strain at three circumferential
E 139 Practice for Conducting Creep, Creep-Rupture, and
3 positions at each of two different longitudinal positions.
Stress-Rupture Tests of Metallic Materials
3.2.7 reduced section of the specimen—the central portion
E 220 Method for Calibration of Thermocouples by Com-
4 of the length having a cross section smaller than that of the
parison Techniques
ends that are gripped. The reduced section is uniform within
E 602 Test Method for Sharp-Notch Tension Testing with
3 tolerances prescribed in Test Methods E 8.
Cylindrical Specimens
3.2.8 stress-rupture test—a test in which time for rupture is
2.2 Military Standard:
measured, no deformation measurements being made during
the test.
4. Significance and Use
These test methods are under the jurisdiction of ASTM Committee E-28 on
Mechanical Testing and is the direct responsibility of Subcommittee E28.10 on
4.1 Rupture life of notched specimens is an indication of the
Effect of Elevated Temperature on Properties.
ability of a material to deform locally without cracking under
Current edition approved July 29, 1983. Published November 1983. Originally
published as E 292 – 66 T. Last previous edition E 292 – 78.
Annual Book of ASTM Standards, Vol 01.01.
Annual Book of ASTM Standards, Vol 03.01. 5
Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700
Annual Book of ASTM Standards, Vol 14.03.
Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
E 292
multi-axial stress conditions, thereby redistributing stresses nized that depending on the test conditions, the fits between
around a stress concentrator. mating parts may deteriorate with time and that furnace seals if
4.2 The notch test is used principally as a qualitative tool in not properly installed could cause lateral forces to be applied to
comparing the suitability of materials for designs that will the loading rods. In either case, misalignments may be in-
contain deliberate or accidental stress concentrators. creased relative to the values measured at room temperature for
new equipment. Axiality requirements and verifications may be
5. Apparatus
omitted when testing performed is for acceptance of material to
5.1 Testing Machine:
minimum strength requirements. As discussed in 5.1.2, exces-
5.1.1 The testing machine shall ensure the application of the sive bending would result in reduced strength or conservative
load to an accuracy of 1 % over the working range.
results. In this light, should acceptance tests pass minimum
5.1.2 The rupture strength of notched or smooth specimens requirements, there would be little benefit to improving axiality
may be reduced by bending stresses produced by eccentricity
of loading. However, if excessive bending resulted in high
of loading (that is, lack of coincidence between the loading rejection rates, economics would probably favor improving
axis and the longitudinal specimen axis). The magnitude of the
axiality.
effect of a given amount of eccentricity will increase with
5.1.5 This requirement is intended to limit the maximum
decreasing ductility of the material and, other things being
contribution of the testing apparatus to the bending that occurs
equal, will be larger for notch than for smooth specimens.
during a test. It is recognized that even with qualified apparatus
Eccentricity of loading can arise from a number of sources
different tests may have quite different percent bending strain
associated with misalignments between mating components of
due to chance orientation of a loosely fitted specimen, lack of
the loading train including the specimen. The eccentricity will
symmetry of that particular specimen, lateral force from
vary depending on how the components of the loading train are
furnace packing and thermocouple wire, etc.
assembled with respect to each other and with respect to the
5.1.6 The testing machine should incorporate means of
attachments to the testing machine. Thus, the bending stress at
taking up the extension of the specimen so that the load will be
a given load can vary from test to test, and this variation may
maintained within the limits specified in 5.1.1. The extension
result in a substantial contribution to the scatter in rupture
of the specimen should not allow the loading system to
strength (1, 2).
introduce eccentricity of loading in excess of the limits
5.1.3 Zero eccentricity cannot be consistently achieved.
specified in 5.1.4. The take-up mechanism should avoid
However, acceptably low values may be consistently achieved
introducing shock loads or torque to the specimen, and
by proper design, machining, and assembly of all components
overloading due to friction, or inertia in the loading system.
of the loading train including the specimen. Devices that will
5.1.7 The testing machine should be erected to secure
isolate the loading train from misalignments associated with
reasonable freedom from vibration and shock due to external
the testing machine may also be used. For cylindrical speci-
causes. Precautions should be made to minimize the transmis-
mens, precision-machined loading train components employ-
sion of shock to neighboring test machines when a specimen
ing either buttonhead, pin, or threaded grips connected to the
fractures.
testing machine through precision-machined ball seat loading
5.1.8 For high-temperature testing of materials that are
yokes have been shown to provide very low bending stresses
readily attacked by their environment (such as oxidation of
when used with commercial creep testing machines (3). How-
metal in air), the sample may be enclosed in a capsule so that
ever, it should be emphasized that threaded connections may
it can be tested in a vacuum or inert gas atmosphere. When
deteriorate when used at sufficiently high temperatures and lose
such equipment is used, the necessary corrections to obtain
their original capability for providing satisfactory alignment.
accurate specimen load must be made. For instance, compen-
5.1.4 Whatever method of gripping is employed, the testing
sation must be made for differences in pressures inside and
machine and loading train components when new should be
outside of the capsule and for any load variation due to sealing
capable of loading a verification specimen at room temperature
ring friction, bellows, or other features.
as described in 7.2 so that the maximum bending strain is 10 %
5.2 Heating Apparatus:
or less at the lowest anticipated load in the creeprupture test. It
is recognized that this measurement will not necessarily 5.2.1 The apparatus for and method of heating the speci-
represent the performance in the elevated-temperature rupture mens should provide the temperature control necessary to
test, but is designed to provide a practical means of evaluating satisfy the requirements specified in 5.3.1 without manual
a given testing machine and its associated loading train adjustment more frequent than once in each 24-h period after
components. Generally, the eccentricity of loading at elevated load application.
temperatures will be reduced by the higher compliance, lower
5.2.2 Heating shall be by an electric resistance or radiation
modulus of various mating parts as compared with the verifi-
furnace with the specimen in air at atmospheric pressure unless
cation test at room temperature. However, it should be recog-
other media are specifically agreed upon in advance.
NOTE 1—The medium in which the specimens are tested may have a
considerable effect on the results of tests. This is particularly true when the
The numbers in boldface type refer to the list of references at the end of this
properties are influenced by oxidation or corrosion during the test.
standard.
E 292
, but also of the absolute size of the
5.3 Temperature Control: theoretical stress concentration, K
t
specimen, even though the various specimens used are geometrically
5.3.1 Indicated specimen temperature variations along the
similar. Therefore, a comparison of material or different conditions of the
reduced section and notch(es) on the specimen should not
same material on the basis of their notch rupture strength can only be
exceed the following limits initially and for the duration of the
made from test results on the same size specimen.
test:
6.4 Numerous different specimen geometries have been
Up to and including 1800 6 3°F (980 6 1.7°C)
used; some cylindrical specimens are suggested in Fig. 1. A
Above 1800 6 5°F (980 6 2.8°C)
similar specimen is described in Specification A 453/A 453M.
5.3.2 The temperature should be measured and recorded at
Separate plain and notched specimens may be used instead of
least once each working day. Manual temperature readings
the combination specimen described in Fig. 1. Suggested flat
may be omitted on non-working days provided the period
specimens are shown in Fig. 2. Notch preparation methods
between reading does not exceed 48 h. Automatic recording
should be chosen to minimize the surface effect and residual
capable of assuring the above temperature limits at the
stresses.
notch(es) may be substituted for manual readings provided the
NOTE 3—Dimensions of specimens are given in inch-pound units, and
record is read on the next working day.
metric units are not always exact arithmetic equivalents (except for
5.3.3 A minimum of one thermocouple at or near each notch
tolerances which are reasonable equivalents) but have been adjusted to
is required if a notch-only specimen is used. If a combination
provide practical equivalents for critical dimensions while retaining
smooth and notched specimen is used, one or more additional
geometric proportionality.
thermocouples will be required. If the unnotched gage section
6.5 Various methods of attachment of the specimen to the
is 1 in. (25.4 mm) or less, a minimum of one additional
loading train may be used. Threaded attachments are shown in
thermocouple placed at the center of the gage section is
Fig. 1 for cylindrical specimens, but buttonhead, tapered, or pin
required. For unnotched gage sections greater than 1 in. (25.4
attached may be used. The flat specimen types shown in Fig. 2
mm) at least two additional thermocouples, at or near the
may be attached through loading yokes and pins or by wedge
fillets, are required.
grips. If sufficient test material is available, the specimen head
5.3.4 The terms “indicated nominal temperature” or “indi-
length may be increased to permit attachment to the loading
cated temperature” mean the temperature that is indicated on
train at a point outside the furnace. Removing the attachment
the specimen by the temperature-measuring device using good
outside the furnace has the advantage that these components
pyrometric practice.
are not subjected to the test temperature and should therefore
5.3.5 The heating characteristics of the furnace and the
have longer useful lives than similar attachments used inside
temperature control system should be studied to determine the
the furnace.
power input, voltage fluctuation, temperature set point, propor-
6.6 Whatever method of gripping is used, care should be
tioning control adjustment, reset adjustment, and control ther-
taken to minimize the eccentricity of loading, and in all cases
mocouple placement necessary to limit transient temperature
the requirements of 5.1.4 for permissible percent bending shall
overshoot and overheating due to set point error. Overheating
be met.
prior to attaining the limits specified in 5.3.1 should not exceed
25°F (14°C) above the indicated nominal test temperature, the
7. Verification and Standard
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