ASTM E855-08(2013)

Standard Test Methods for Bend Testing of Metallic Flat Materials for Spring Applications Involving Static Loading

SIGNIFICANCE AND USE
4.1 Measurements of bending strength and modulus of elasticity in bending should be made for materials whose principal stressing mode is bending. For many materials, the tensile and compressive moduli are somewhat different. Since the bending modulus is a combination of the tensile and compressive moduli, it is often different from each of them.  
4.2 Precise measurements of the modulus of elasticity in bending and bending strength require due regard for numerous variables that may affect their determination. These include (1) characteristics such as specimen orientation with respect to the rolling direction, grain size, residual stresses, previous strain history, dimensions and specimen preparation, orientation of deformed grains relative to the direction of the normal stress; and (2) test conditions, such as tem- perature, temperature variations, condition of the test equipment and adherence to the recommended test procedure.
SCOPE
1.1 This standard describes three test methods2 for determining the modulus of elasticity in bending and the bending strength of metallic strips or sheets intended for the use in flat springs:  
1.1.1 Test Method A—a cantilever beam,  
1.1.2 Test Method B—a three-point loaded beam (that is, a beam resting on two supports and centrally loaded), and  
1.1.3 Test Method C—a four-point loaded beam (that is, a beam resting on two supports and loaded at two points equally spaced from each support).  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
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: 31-Mar-2013
• ICS: 21.160 - Springs
• Technical Committee: E28 - Mechanical Testing
• Drafting Committee: E28.02 - Ductility and Formability

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E855 − 08 (Reapproved 2013)
Standard Test Methods for
Bend Testing of Metallic Flat Materials for Spring
1
Applications Involving Static Loading
This standard is issued under the fixed designation E855; 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 E177 Practice for Use of the Terms Precision and Bias in
2 ASTM Test Methods
1.1 This standard describes three test methods for deter-
E691 Practice for Conducting an Interlaboratory Study to
mining the modulus of elasticity in bending and the bending
Determine the Precision of a Test Method
strength of metallic strips or sheets intended for the use in flat
springs:
3. Terminology
1.1.1 Test Method A—a cantilever beam,
1.1.2 Test Method B—a three-point loaded beam (that is, a 3.1 Definitions of Terms Specific to This Standard:
beam resting on two supports and centrally loaded), and
3.1.1 In addition to the terms in Terminology E6, the
1.1.3 Test Method C—a four-point loaded beam (that is, a
following descriptions of terms apply in connection with these
beam resting on two supports and loaded at two points equally
test methods for determining bend properties:
spaced from each support).
3.1.2 bend properties—those properties of a material that
1.2 The values stated in inch-pound units are to be regarded are associated with elastic and inelastic behavior when a
bending force is applied, or that involve the relationship
as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only between bending stress and strain.
and are not considered standard. −2
3.1.3 bending stress at outer fiber (FL )—the nominal
1.3 This standard does not purport to address all of the
stressintheouterfibersofabeamresultingfromapplicationof
safety concerns, if any, associated with its use. It is the
a bending load.
responsibility of the user of this standard to establish appro-
−2
3.1.4 elastic limit in bending (FL )—the greatest bending
priate safety and health practices and determine the applica-
stress that a material is capable of sustaining without perma-
bility of regulatory limitations prior to use.
nent strain remaining after complete release of the bending
moment.
2. Referenced Documents
−2
3.1.5 modulus of elasticity in bending (FL )—the ratio of
2.1 The following documents of the issue in effect on date
bending stress to corresponding strain below the elastic limit in
of use of these test methods form a part of these test methods
bending.
to the extent referenced herein:
3
3.1.6 span length (L)—the distance between supports.
2.2 ASTM Standards:
E4 Practices for Force Verification of Testing Machines
3.1.7 uniform bending moment (FL)—a bending moment
E6 Terminology Relating to Methods of Mechanical Testing
that produces a uniform strain at the outer fibers throughout the
E111 Test Method for Young’s Modulus, Tangent Modulus,
gage length of the specimen.
and Chord Modulus
−2
3.1.8 bending proof strength (FL )—the nominal stress in
the outer fibers of a beam that results in a specific permanent
1 strain in the outer fibers upon unloading.
These test methods are under the jurisdiction of ASTM Committee E28 on
Mechanical Testing and are the direct responsibility of Subcommittee E28.02 on
−2
3.1.9 cyclic bending yield strength (FL )—the maximum
Ductility and Formability.
nominalstressinuniformcyclicbendingresultingfromagiven
Current edition approved April 1, 2013. Published April 2013. Originally
approved in 1981. Last previous edition approved in 2008 as E855 – 08. DOI:
plastic deformation in the outer fibers of a beam.
10.1520/E0855-08R13.
−2
2
3.1.10 offset yield strength in bending (FL )—thenominal
Method D, which appeared in the last previous edition, was dropped because of
the unavailability of commercial testing equipment.
stress in the outer fibers of a beam in bending at which a
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
specified limiting deviation from proportionality of bending
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
stress to bending strain is exhibited.The deviation is expressed
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. in terms of strain.
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E855 − 08 (2013)
4. Significance and Use 8. Significance and Use
8.1 This test method may be used for obtaining values of
4.1 Measurements of bending strength and modu
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