ASTM E517-00(2006)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:E517–00 (Reapproved 2006)
Standard Test Method for
Plastic Strain Ratio r for Sheet Metal
This standard is issued under the fixed designation E517; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.1.1 Discussion—In cold-reduced and annealed low-
carbonsteelsheet, r and r areusuallygreaterthan r ,while
1.1 This test method covers special tension testing for the 0 90 45
in hot-rolled steels r may be greater. Other earing tendencies
measurement of the plastic strain ratio, r, of sheet metal
occur; thus, for some materials the earing tendency may be
intended for deep-drawing applications.
better represented by r − r .
max min
1.2 The values stated in inch-pound units are to be regarded
3.1.2 plastic-strain ratio r (in sheet metal that has been
as standard. The values given in parentheses are mathematical
strained by uniaxial tension sufficiently to induce plastic flow)
conversions to SI units that are provided for information only
is the ratio of the true strain that has occurred in a width
and are not considered standard.
direction w perpendicular to the direction of applied stress and
1.3 This standard does not purport to address all of the
in the plane of the sheet, to the concomitant true strain in the
safety concerns, if any, associated with its use. It is the
thickness direction t. Thus, r is numerically equal to
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- r 5e /e (1)
w t
bility of regulatory limitations prior to use.
where:
e = width strain, and
2. Referenced Documents
w
e = thickness strain.
t
2.1 ASTM Standards:
3.1.2.1 Discussion—Due to difficulty in measuring thick-
E6 Terminology Relating to Methods of Mechanical Test-
nesschangeswithsufficientprecision,inpracticeanequivalent
ing
relationship is commonly used, based on length and width
E8 Test Methods for Tension Testing of Metallic Materials
strain measurements (see 9.1.2).
E83 Practice for Verification and Classification of Exten-
3.1.3 r —weighted average of r values obtained in three
m
someter Systems
directions:0°(parallel),45°(diagonal),and90°(transverse)to
E92 Test Method for Vickers Hardness of Metallic Mate-
the rolling direction (see 10.3).
rials
3.1.3.1 Discussion—Somematerialsmayshowsignificantly
E177 Practice for Use of the Terms Precision and Bias in
different values of r for other test directions, in which case an
ASTM Test Methods
averagevaluemayincludethesewhenspecialnoteismadeand
E691 Practice for Conducting an Interlaboratory Study to
another subscript is used to avoid confusion with r as defined
m
Determine the Precision of a Test Method
in3.1.3.Symbolswhichareoftenusedinterchangeablywithr
m
are r¯ and r-Bar.
3. Terminology
3.1.4 yield point elongation (for a material that has a yield
3.1 Definitions of Terms Specific to This Standard:
point)isthetotalstrainassociatedwithdiscontinuousyielding.
3.1.1 delta r (D r)—measure of the tendency of sheet to
3.2 The definitions relating to tension testing appearing in
draw in nonuniformly and to form ears in the flange of
TerminologyE6 shall apply to this test method.
deep-drawn cylindrical parts in the directions of higher r value
(see 10.4).
4. Significance and Use
4.1 Theplasticstrainratio risaparameterthatindicatesthe
ability of a sheet metal to resist thinning or thickening when
This test method is under the jurisdiction of ASTM Committee E28 on
subjectedtoeithertensileorcompressiveforcesintheplaneof
Mechanical Testing and is the direct responsibility of Subcommittee E28.02 on
the sheet. It is a measure of plastic anisotropy and is related to
Ductility and Flexure.
the preferred crystallographic orientations within a polycrys-
Current edition approved Sept. 1, 2006. PublishedSeptember 2006. Originally
approved in 1981. Last previous edition approved in 2000 as E517–00.
talline metal. This resistance to thinning or thicken-ing con-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
tributes to the forming of shapes, such as cylindrical flat-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
bottom cups, by the deep-drawing process. The r value,
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. therefore,isconsideredameasureofsheetmetaldrawability.It
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E517–00 (2006)
isparticularlyusefulforevaluatingmaterialsintendedforparts extensometersshallbeverifiedoverarangeappropriateforthe
where a substantial portion of the blank must be drawn from strains used to determine r value.
beneath the blank holder into the die opening. 6.2 Testing Machine—The testing machine used to strain
4.2 For many materials this ratio remains essentially con- the specimen shall be capable of uniaxially straining the
stant over a range of plastic strains up to maximum applied specimeninaccordancewiththerequirementsin9.2.5or9.3.4.
forceinatensiontest.Formaterialsthatgivedifferent rvalues
7. Test Specimen
at various strain levels, a superscript is used to designate the
7.1 Size—The length and width of the specimen are not
percentstrainatwhichthe rvaluewasmeasured.Forexample,
critical, provided care is used to stretch the gauge section in a
if a 20% elongation is used, the report would show r .
uniform manner, avoiding grip effects and anomalous changes
4.3 Materials usually have different r values when tested in
along the gauge lengths.
differentorientationsrelativetotherollingdirection.Theangle
7.1.1 The specimen shall include the full sheet thickness
of sampling of the individual test coupon is noted by a
unless otherwise specified.
subscript. Thus, for a test specimen whose length is aligned
7.1.2 The thickness of the gauge section of the specimen
parallel to the rolling direction, the r value would be reported
shall be uniform within 0.0005 in. (0.013 mm) in the gauge
as r . If, in addition, the measurement was made at 20%
elongation and it was deemed necessary to note the percent section. If the as-received surface is nonuniform, the surface
shallbepreparedbymachiningorbygrindingtothistolerance.
strain at which the value was measured, the value would be
reported as r . 7.1.3 Thedistancebetweenagaugemarkandagripshallbe
at least twice the width of the reduced section (or gauge width
4.4 A material that has a yield point followed by discon-
tinuous yielding stretches unevenly while this yielding is for parallel strips) of the specimen.
7.1.4 Duplicate specimens should be tested and the average
takingplace.Insteels,thisisassociatedwiththepropagationof
Lüders’bandsonthesurface.Theaccuracyandreproducibility r value of these reported for each test direction. If necessary, a
third determination may be made, rejecting the extreme.
of the determination of r will be reduced unless the test is
7.2 Type—Any of three types of specimen may be used.
continued beyond this yield-point elongation. Similarly, the
Other types including subsize specimens are acceptable pro-
discontinuous yielding associated with large grain size in a
vided they give comparable values of equivalent accuracy.
material decreases the accuracy and reproducibility of deter-
7.2.1 Specimen A, with reduced section, as shown in Fig.
minations of r made at low strains.
1—While this is similar to Fig. 6 of Test Methods E8, the
5. Interferences
reduced section shall be parallel-sided rather than tapered.
5.1 Many factors may affect the measurements taken for 7.2.2 Specimen B, with a uniform width of 0.75 in. (20 mm),
determining rvalue.Inparticular,errorsinthemeasurementof machined edges, and no reduced section, as shown in Fig. 2.
the change in width can cause the reported r value to be 7.2.3 Specimen C, precision-sheared a uniform width of
invalid. The following phenomena are known to cause severe 1.125 in. (28.58 mm), or with machined edges and no reduced
errorsinthemeasurementofthechangeinwidththusaffecting section, as shown in Fig. 3.
the r value reported. 7.2.3.1 gauge lengths for Specimen C shall be marked on
5.1.1 Canoeing—Canoeing is a phenomenon which occurs the sheet surface perpendicular to and parallel to the specimen
in some materials when they are stretched. In these materials, edges. The gauge marks shall be made with Vickers diamond
the test specimen bows about its longitudinal axis taking on a indenters described in Test Method E92, or similar precise
shaperesemblingthebottomofacanoe.Inthiscase,unlessthe marks.
measurements of the change in width are compensated for,
8. Specimen Preparation
there will be significant errors in the r value calculated.
8.1 Specimen blanks shall be sheared or sawed individually
5.1.2 Sharp Knife Edges—Knife edges, used to measure the
changeinwidthautomatically,whilethespecimenisstretched, and with the exception of Specimen C, which may be used as
sheared, shall be machined individually or in packs to remove
may cause localized deformation of the specimen under the
knife edges. This problem is intensified by the knife edges cold-worked edges.
8.2 The dimensions of each specimen shall be measured for
beingsharpandattachedtothespecimenwithhighforces.This
uniformity of thickness and width in the gauge section to meet
combination produces a compressive stress 90° to the tensile
the requirements of 7.1.2 and 8.3.
stress being applied to stretch the specimen, which causes
8.3 Within the gauge length, parallelism of the edges shall
localized deformation. As a result, excessively high r values
be maintained so that no two width measurements differ by
may be calculated.
more than 0.1% of the measured width (Specimens A and B
6. Apparatus
only).
6.1 Measuring Devices: 8.4 Reasonable care shall be taken to position the gauge
6.1.1 Instruments for measuring length and width shall be marks symmetrically to the midpoint and centerline of the
checkedforaccuracyandbegraduatedtopermitmeasurements specimen or reduced section.
to be made to 60.001 in. (6 0.02 mm) or better. 8.4.1 Gaugemarksshallbelightlyscribedorpunchedinthe
6.1.2 If the longitudinal strain or the transverse strain, or surface of the specimen or made with a Vickers diamond
both, are to be obtained using an extensometer, the extensom- indenter.
eter shall conform to PracticeE83 as Class C or better. The 8.4.2 The gauge lengths shall be in compliance with 7.1.3.
E517–00 (2006)
Dimensions
Specimen A
Standard Alternative
in. mm in. mm
G Gage length 2.00 6 0.01 506 0.25 1.00 6 0.005 25 6 0.13
W Width (Note 2 and Note 3) 0.500 6 0.01 12.5 6 0.25 0.500 6 0.01 12.5 6 0.025
T Thickness thickness of material thickness of material
1 1
R Radius of fillet, min ⁄2 13 ⁄2 13
L Overall length, min 8 200 7 ⁄4 180
A Length of reduced section, min 3 75 2 ⁄4 60
B Length of grip section, min 2 50 2 50
3 3
C Width of grip section, approximate ⁄4 20 ⁄4 20
NOTE 1—The edges of the reduced section shall be machined parallel over the gage length within a tolerance of 0.0005 in. (0.012 mm).
NOTE 2—The ends of the reduced section shall not differ in width by more than 0.005 in. or 0.013 mm. However, the width within the gage length
must conform to 8.3.
FIG. 1 Rectangular Tension Test Specimens with Reduced Parallel Section, for r Determination
Dimensions
Specimen B
Standard Alternative
in. mm in. mm
G gauge length 2.00 6 0.01 50 6 0.25 1.00 6 0.005 25 6 0.13
W gauge width 0.756 0.005 206 0.13 0.756 0.005 206 0.13
T Thickness thickness of material
L Overall length, min 8 200 7 175
C Width of specimen (Note) 0.75 6 0.005 20 6 0.13 0.756 0.005 20 6 0.13
NOTE 1—Edges of Specimen B shall be machined parallel over the full length within a tolerance of 0.0008 in. (0.020 mm).
FIG. 2 Machined Rectangular Tension Test Specimens, Parallel Strip, for r Determination
8.4.3 For SpecimenA, the gauge length shall be centered in 9.1.1 The plastic strain ratio r may be determined from
the reduced section.
widthandthicknesschangesresultingfromplasticdeformation
8.4.4 For Specimen C, a double set of gauge marks shall be
provided these changes can be measured with sufficient accu-
used in compliance with 7.2.3.1.
racy in a tension test.
9.1.2 Formostthinsheetmetals,however,itispreferableto
9. Procedure
measure length and width changes and, assuming constant
9.1 If the tensile properties of the material are unknown,
volume, calculate r by one of the following procedures:
either make an autographic force/extension record or run a
9.2 Manual Procedure:
separate tension test to determine the yielding characteristics
9.2.1 Determine the original width of the specimen, w ,
and the elongation in accordance withTest MethodsE8, using 0
within 60.0005 in. (60.013 mm). If a gauge length of 0.75 in.
the specimen shown in Fig. 6 of Test MethodsE8. This will
(20 mm) is used, as for Specimen C, one width measurement
establish strain limits within which the r determination may be
made. is sufficient. If a gauge length of 1.00 in. or (25 mm) or longer
E517–00 (2006)
Dimensions
Specimen C
in. mm
G Gage Length 0.75 6 0.005 20 6 0.13
W Gage Width 0.75 6 0.005 20 6 0.13
T Thickness thickness of material
L Overall Length, min 7 175
C Width of specimen 1.125 6 0.125 28.58 6 3.17
FIG. 3 Sheared Rectangular Tension Test Specimen, Parallel
Strip, for r Determination
is used, make width measurements at a minimum of three force. Measurement accuracy is improved as the strain is
evenly spaced places within the gauge length and use the increased within the above limits, as explained in X1.3.3.1.
average.
NOTE 2—For complete compatibility with the manual method, only the
9.2.2 Measure the original gauge length, l , within 60.001
plastic component of the strain values measured should be used in the
in. (60.025 mm) in a 1.00-in. (25-mm), or a 0.75-in. (20-mm)
determination of the r value by the automatic method, unless it can be
gaugesection,andwithin 60.002in.(60.05mm)ina2.00-in. shown that the elastic component of the total strain is negligible. (The
error in calculated r value decreases with increasing strain, higher
(50-mm) gauge section.
modulus, lower strength, and at lower r values.) Plastic strains can be
9.2.3 When gauge marks are made with two indenters
determined by reducing the tensile force on the specimen to zero with the
mounted a known distance apart in a fixture, only final gauge
extensometersinplace,ortheycanbecalculatedbysubtractingtheel
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