ASTM B593-96(2003)
(Test Method)Standard Test Method for Bending Fatigue Testing for Copper-Alloy Spring Materials
Standard Test Method for Bending Fatigue Testing for Copper-Alloy Spring Materials
SCOPE
1.1 This test method describes procedures for the determination of the reversed or repeated bending fatigue properties of copper alloy flat-sheet or strip-spring materials by fixed cantilever, constant amplitude of displacement-type testing machines. This method is limited to flat stock ranging in thickness from 0.005 to 0.062 in. (0.13 to 1.57 mm), to a fatigue-life range of 105 to 108 cycles, and to conditions where no significant change in stress-strain relations occurs during the test.
Note 1—This implies that the load-deflection characteristics of the material do not change as a function of the number of cycles within the precision of measurement. There is no significant cyclic hardening or softening.
1.2 The values stated in inch-pound units are to be regarded as the standard. SI values given 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.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: B 593 – 96 (Reapproved 2003)
Standard Test Method for
Bending Fatigue Testing for Copper-Alloy Spring Materials
This standard is issued under the fixed designation B 593; 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.
1. Scope* cantilever, constant-deflection type fatigue testing machine.
The specimen is held at one end, acting as a cantilever beam,
1.1 This test method describes procedures for the determi-
and cycled by flexure followed by reverse flexure until
nation of the reversed or repeated bending fatigue properties of
complete failure. The number of cycles to failure is recorded as
copper alloy flat-sheet or strip-spring materials by fixed canti-
a measure of fatigue-life.
lever, constant amplitude of displacement-type testing ma-
chines. This method is limited to flat stock ranging in thickness
5. Significance and Use
from 0.005 to 0.062 in. (0.13 to 1.57 mm), to a fatigue-life
5 8
5.1 The flexural fatigue test described in this test method
range of 10 to 10 cycles, and to conditions where no
provides information on the ability of a copper alloy flat-spring
significant change in stress-strain relations occurs during the
material to resist the development of cracks or general me-
test.
chanical deterioration as a result of a relatively large number of
5 8
NOTE 1—This implies that the load-deflection characteristics of the
cycles (generally in the range 10 to 10 ) under conditions of
material do not change as a function of the number of cycles within the
constant displacement.
precision of measurement. There is no significant cyclic hardening or
5.2 This test method is primarily a research and develop-
softening.
ment tool which may be used to determine the effect of
1.2 The values stated in inch-pound units are to be regarded
variations in materials on fatigue strength and also to provide
as the standard. SI values given in parentheses are for infor-
data for use in selecting copper alloy spring materials for
mation only.
service under conditions of repeated strain cycling.
1.3 This standard does not purport to address all of the
5.3 The results are suitable for direct application in design
safety concerns, if any, associated with its use. It is the
only when all design factors such as loading, geometry of part,
responsibility of the user of this standard to establish appro-
frequency of straining, and environmental conditions are
priate safety and health practices and determine the applica-
known. The test method is generally unsuitable for an inspec-
bility of regulatory limitations prior to use.
tion test or a quality control test due to the amount of time and
effort required to collect the data.
2. Referenced Documents
2.1 ASTM Standards:
6. Apparatus
E 206 Definitions of Terms Relating to Fatigue Testing and
6.1 Testing Machine—The fatigue testing machine is a
the Statistical Analysis of Fatique Data
fixed-cantilever, constant-deflection type. In this machine (Fig.
E 468 Practice for Presentation of Constant Amplitude Fa-
1) the test specimen shall be held as a cantilever beam in a
tigue Test Results for Metallic Materials
clamp at one end and deflected by a concentrated load applied
near the other end of the apex of the tapered section (Fig. 2).
3. Terminology
Either the clamp or the loading member may be adjusted so
3.1 For terminology relating to this test method, refer to
that the deflection of the free end of the cantilever is either
Definitions E 206 and Practice E 468.
completely reversed (mean displacement equal to zero) or
greater in one direction of bending (mean displacement not
4. Summary of Test Method
equal to zero).
4.1 A prepared test specimen of a specific wrought copper
6.2 A suitable counter and monitoring circuit is required to
alloy flat-sheet or strip-spring material is mounted into a fixed
provide a direct readout of the number of cycles to complete
failure, that is, separation into two pieces.
This test method is under the jurisdiction of ASTM Committee B05 on Copper
7. Test Specimen
and Copper Alloys and is the direct responsibility of Subcommittee B05.06 on
Methods of Test.
7.1 The test specimen shall be of the fixed-cantilever type.
Current edition approved Apr. 10, 2003. Published June 2003. Originally
Several such specimens which have been used successfully are
approved in 1973. Last previous edition approved in 1996 as B593 – 96.
shown in Fig. 2.
Discontinued, see 1986 Annual Book of ASTM Standards, Vol 03.01.
Annual Book of ASTM Standards, Vol 03.01.
*A Summary of Changes section appears at the end of this standard.
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
B 593 – 96 (2003)
FIG. 1 Fatigue Machines
7.2 It is important, therefore, that care be exercised in the 7.4 Test specimens from material that is used in a thermally
preparation of test specimens, particularly in machining, to treated condition, such as precipitation hardened or stress
assure good workmanship. Improperly prepared test specimens
relieved, shall be treated in a manner reflecting the way the
cause unsatisfactory test results.
material will be used. The procedure used should be noted in
7.2.1 The specimens are best prepared by cross milling a
reporting test results.
stack, approximately 0.75 in. (19 mm) thick, including back-up
plates, for which 0.12-in. (3-mm) thick brass sheet stock may
8. Calculation of Stress
be used.
8.1 The maximum bending stress is calculated by using the
7.2.1.1 It is necessary to ensure that any cutting or machin-
simple beam equation:
ing operation required to either rough cut the test specimen
from the blank, or to machine it to size does not appreciably
S 5 6PL/bd (1)
alter the metallurgical structure or properties of the material.
where:
All cuts taken in machining should be such as to minimize
S = desired bending stress, lb/in. ,
work hardening of the test specimen.
P = applied load at the connecting pin (apex of triangle), lb,
7.2.1.2 In selecting cutting speeds and feed rates, due regard
L = distance between the connecting pin and the point of
should be paid to the test-specimen material, and for finishing
stress, in.,
cuts, to the quality of the surface finish required.
b = specimen width at length L from point
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