ASTM B593-96

Standard Test Method for Bending Fatigue Testing for Copper-Alloy Spring Materials

SCOPE
1.1 This 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 10  to 10  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

• Status: Historical
• Publication Date: 09-Sep-1996
• Technical Committee: B05 - Copper and Copper Alloys
• Drafting Committee: B05.06 - Methods of Test

Relations

• Replaced By: ASTM B593-96(2003) - Standard Test Method for Bending Fatigue Testing for Copper-Alloy Spring Materials
• Effective Date: 10-Apr-2003

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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.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
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 signifi-
provides information on the ability of a copper alloy flat-spring
cant change in stress-strain relations occurs during the test.
material to resist the development of cracks or general me-
NOTE 1—This implies that the load-deflection characteristics of the
chanical deterioration as a result of a relatively large number of
material do not change as a function of the number of cycles within the
5 8
cycles (generally in the range 10 to 10 ) under conditions of
precision of measurement. There is no significant cyclic hardening or
constant displacement.
softening.
5.2 This test method is primarily a research and develop-
1.2 The values stated in inch-pound units are to be regarded
ment tool which may be used to determine the effect of
as the standard. SI values given in parentheses are for infor-
variations in materials on fatigue strength and also to provide
mation only.
data for use in selecting copper alloy spring materials for
1.3 This standard does not purport to address all of the
service under conditions of repeated strain cycling.
safety concerns, if any, associated with its use. It is the
5.3 The results are suitable for direct application in design
responsibility of the user of this standard to establish appro-
only when all design factors such as loading, geometry of part,
priate safety and health practices and determine the applica-
frequency of straining, and environmental conditions are
bility of regulatory limitations prior to use.
known. The test method is generally unsuitable for an inspec-
tion test or a quality control test due to the amount of time and
2. Referenced Documents
effort required to collect the data.
2.1 ASTM Standards:
E 206 Definitions of Terms Relating to Fatigue Testing and
6. Apparatus
the Statistical Analysis of Fatique Data
6.1 Testing Machine—The fatigue testing machine is a
E 468 Practice for Presentation of Constant Amplitude Fa-
fixed-cantilever, constant-deflection type. In this machine (Fig.
tigue Test Results for Metallic Materials
1) the test specimen shall be held as a cantilever beam in a
clamp at one end and deflected by a concentrated load applied
3. Terminology
near the other end of the apex of the tapered section (Fig. 2).
3.1 For terminology relating to this test method, refer to
Either the clamp or the loading member may be adjusted so
Definitions E 206 and Practice E 468.
that the deflection of the free end of the cantilever is either
completely reversed (mean displacement equal to zero) or
4. Summary of Test Method
greater in one direction of bending (mean displacement not
4.1 A prepared test specimen of a specific wrought copper
equal to zero).
alloy flat-sheet or strip-spring material is mounted into a fixed
6.2 A suitable counter and monitoring circuit is required to
provide a direct readout of the number of cycles to complete
1 failure, that is, separation into two pieces.
This test method is under the jurisdiction of ASTM Committee B-5 on Copper
and Copper Alloys and is the direct responsibility of Subcommittee B05.06 on
7. Test Specimen
Methods of Test.
Current edition approved Sept. 10, 1996. Published November 1996. Originally
7.1 The test specimen shall be of the fixed-cantilever type.
published as B593 – 73. Last previous edition B593 – 85 (1990).
Several such specimens which have been used successfully are
Discontinued, see 1986 Annual Book of ASTM Standards, Vol 03.01.
Annual Book of ASTM Standards, Part 03.01. shown in Fig. 2.
*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.
B593–96
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 poi
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