ASTM E517-24

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Designation: E517 − 19 E517 − 24
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. 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*
1.1 This test method covers special tension testing for the measurement of the plastic strain ratio, r, of sheet metal intended for
deep-drawing applications.
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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
E6 Terminology Relating to Methods of Mechanical Testing
E8/E8M Test Methods for Tension Testing of Metallic Materials
E83 Practice for Verification and Classification of Extensometer Systems
E92 Test Methods for Vickers Hardness and Knoop Hardness of Metallic Materials
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1 Definitions of Terms Common to Mechanical Testing:
3.1.1 The definitions relating to tension testing appearing in Terminology E6 shall apply to this test method. Some of those
important terms include discontinuous yielding, gauge length, axial strain, true strain, reduced section, yield-point elongation, and
upper yield strength.
3.2 Definitions of Terms Specific to This Standard:
This test method is under the jurisdiction of ASTM Committee E28 on Mechanical Testing and is the direct responsibility of Subcommittee E28.02 on Ductility and
Formability.
Current edition approved Oct. 1, 2019March 1, 2024. Published October 2019April 2024. Originally approved in 1981. Last previous edition approved in 20182019 as
E517 – 18.E517 – 19. DOI: 10.1520/E0517-19.10.1520/E0517-24.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E517 − 24
3.2.1 axial gauge length, l , n—a gauge length aligned with the long axis of the specimen.
i
3.2.1.1 Discussion—
The specific measurement to be used for the axial gauge length is based on which procedure (Manual,Automatic, or Combined)
and specimen type are used.
3.2.1.2 Discussion—
Since “gauge length” is by definition the original length, the final length associated with the axial gauge length would be the final
axial length, l .
f
3.2.1.3 Discussion—
In uniaxial testing, dimensions aligned with the longitudinal or long axis of the specimen are frequently referred to as “axial”
dimensions, for example, axial gauge length. The word “longitudinal” describes the long-axis direction of the specimen and has
no assumed relationship to the rolling direction of the sheet metal being tested.
3.2.2 earing tendency, delta r or ∆r, n—measure of the tendency of sheet to draw in nonuniformly and to form ears in the flange
of deep-drawn cylindrical parts in the directions of higher values of r (see 10.4).
3.2.2.1 Discussion—
In cold-reduced and annealed low-carbon steel sheet, r and r are usually greater than r , while in hot-rolled steels r can be
0 90 45 45
greater. Other earing tendencies occur; thus, for some materials the earing tendency can be better represented by r − r .
max min
3.2.3 plastic strain ratio, r, n—in sheet metal that has been strained by uniaxial tension sufficiently to induce plastic flow, the ratio
of the true strain that has occurred in a widthtransverse direction (ɛ w) perpendicular to the direction of applied stress and in the
w
plane of the sheet, to the concomitant true strain in the thickness direction (ɛ t.).
t
3.2.3.1 Discussion—
The plastic strain ratio, r, is numerically equal to
r 5 ε /ε (1)
w t
where:
ε = width strain, and
w
ε = thickness strain.
t
ε = true transverse strain, and
w
ε = true thickness strain.
t
3.2.3.2 Discussion—
Due to difficulty in measuring thickness changes with sufficient precision, in practice an equivalent relationship is commonly used,
based on length and widthaxial and transverse strain measurements (see 9.1.2).
3.2.3.3 Discussion—
The term “transverse” describes the width direction of the specimen and has no assumed relationship to the rolling direction of
the sheet metal being tested.
3.2.4 reduced parallel section, n—the central portion of the specimen that has a nominally uniform cross section, that is smaller
than that of the ends that are gripped, not including the fillets.
3.2.4.1 Discussion—
This term is often called the “parallel length” in other standards.
3.2.4.2 Discussion—
This term is very similar to the Terminology E6 term “reduced parallel section”, except in this standard the tolerance on the reduced
parallel section parallelism is much tighter, as shown in Fig. 1.
3.2.5 transverse gauge length, w , n—in sheet products, a gauge length aligned across the width of the specimen and perpendicular
i
to the axial gauge length.
3.2.5.1 Discussion—
The specific measurement to be used for the transverse gauge length is based on which procedure (Manual,Automatic, or
Combined) and specimen type are used.
3.2.5.2 Discussion—
Since “gauge length” is by definition the original length, the final length associated with the transverse gauge length would be the
final transverse length, w .
f
E517 − 24
+ gauge mark or extensometer
Dimensions
Specimen A
Standard Alternative
in. mm in. mm
G Gauge length 2.00 ± 0.01 50± 0.25 1.00 ± 0.005 25 ± 0.13
G Axial gauge mark 2.00 ± 0.01 50 ± 0.25 1.00 ± 0.005 25 ± 0.13
spacing
W Width (Note 1 and 0.500 ± 0.01 12.5 ± 0.25 0.500 ± 0.01 12.5 ± 0.25
Note 2)
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 3 75 2 ⁄4 60
parallel section, min
B Length of grip section, 2 50 2 50
min
3 3
C Width of grip section, ⁄4 20 ⁄4 20
approximate
NOTE 1—The edges of the reduced parallel section shall be machined parallel over thelength, gaugeG, length within a tolerance of 0.0005 in.
(0.012(0.01 mm).
NOTE 2—The ends of the reduced parallel section shall not differ in width by more than 0.005 in. or 0.013 mm.(0.1 mm). However, the width within
the gauge length G shall conform to 8.3.
FIG. 1 Rectangular Tension Test Specimens with Reduced Parallel SectionSection, Specimen A
3.2.5.3 Discussion—
Since the thickness of the specimen is also referred to in this test method, the symbol w is used for the transverse length rather
than t to prevent confusion with the measurements in the thickness direction.
3.2.5.4 Discussion—
The term “transverse” describes the width direction of the specimen and has no assumed relationship to the rolling direction of
the sheet metal being tested.
3.2.6 transverse strain, n—in sheet products, linear strain in the plane of the specimen perpendicular to the longitudinal axis of
the specimen.
3.2.6.1 Discussion—
This definition of transverse strain, in sheet products, is a more specific version of the term “transverse strain” as defined in
Terminology E6, but transverse strain in sheet products is limited to the width direction of the specimen.
3.2.6.2 Discussion—
The true transverse strain is denoted as ε in this standard.
w
3.2.6.3 Discussion—
The terms “transverse” and “longitudinal” describe the in-plane directions of the specimen and have no assumed relationship to
the rolling direction of the sheet metal being tested.
3.2.7 thickness strain, n—in sheet products, linear strain through the thickness of the specimen perpendicular to the longitudinal
axis of the specimen.
3.2.7.1 Discussion—
This definition of thickness strain, in sheet products, is a more specific version of the term “transverse strain” as defined in
Terminology E6, but thickness strain in sheet products is limited to the thickness direction of the specimen.
3.2.7.2 Discussion—
The true thickness strain is denoted as ε in this standard.
t
E517 − 24
3.2.7.3 Discussion—
The terms “transverse” and “longitudinal” describe the in-plane directions of the specimen and have no assumed relationship to
the rolling direction of the sheet metal being tested.
3.2.8 weighted-average plastic strain ratio, r , n—the weighted average of values of r obtained in three in-plane directions: 0°
m
(parallel), 45° (diagonal), and 90° (transverse) to the rolling direction.
3.2.8.1 Discussion—
Some materials exhibit significantly different values of plastic strain ratio, r, for other test directions, in which case the
weighted-average plastic strain ratio may include these values when special note is made and another subscript is used to avoid
confusion with r as defined in 3.2.33.2.8.
m
3.2.8.2 Discussion—
Symbols that are often used interchangeably with r are r¯ and r-Bar.
m
4. Significance and Use
4.1 The plastic strain ratio r is a parameter that indicates the ability of a sheet metal to resist thinning or thickening when subjected
to either tensile or compressive forces in the plane of the sheet. It is a measure of plastic anisotropy and is related to the preferred
crystallographic orientations within a polycrystalline metal. This resistance to thinning or thickening contributes to the forming of
shapes, such as cylindrical flat-bottom cups, by the deep-drawing process. The value of r, therefore, is considered a measure of
sheet-metal drawability. It is particularly useful for evaluating materials intended for parts where a substantial portion of the blank
is drawn from beneath the blank holder into the die opening.
4.2 For many materials the plastic strain ratio remains essentially constant over a range of plastic strains up to maximum applied
force in a tension test. For materials that give different values of r at various strain levels, a superscript is used to designate the
percent strain at which the value of r was measured. For example, if a 20 % elongation is used, the report would show r .
4.3 Materials usually have different values of r when tested in different orientations relative to the rolling direction. The angle of
sampling of the individual test specimen is noted by a subscript. Thus, for a test specimen whose length is aligned parallel to the
rolling direction, plastic strain ratio, r, is reported as r . If, in addition, the measurement was made at 20 % elongation and it was
deemed necessary to note the percent strain at which the value was measured, the value would be reported as r .
4.4 A material that has an upper yield strength (yield point) point followed by discontinuous yielding stretches unevenly while this
yielding is taking place. In steels, this is associated with the propagation of Lüders’Lüders’ bands on the surface. The accuracy and
reproducibility of the determination of plastic strain ratio, r, will be reduced unless the test is continued beyond this yield-point
elongation. Similarly, the discontinuous yielding associated with large grain size in a material decreases the accuracy and
reproducibility of determinations of plastic strain ratio, r, made at low strains.
5. Interferences
5.1 Many factors affect the measurements taken for determining the value of r. In particular, errors in the measurement of the
change in width can cause the reported the value of r to be invalid. The following phenomena are known to cause severe errors
in the measurement of the change in width and affect the value of r reported.
5.1.1 Canoeing—Canoeing is a phenomenon that occurs in some materials when they are stretched. In these materials, the test
specimen bows about its longitudinal axis and takes on a shape resembling the bottom of a canoe. In this case, unless the transverse
measurements of the change in width are compensated for, there will be significant errors in the calculated value of r.
5.1.2 Sharp Knife Edges—Knife edges, used to measure the transverse change in width automatically, while the specimen is
stretched, stretched longitudinally, can cause localized deformation of the specimen under the knife edges. This problem is
intensified if the knife edges are sharp and attached to the specimen with high forces. This combination produces a compressive
stress 90° to the tensile stress being applied to stretch the specimen, which causes localized deformation. As a result, excessively
high values of r are calculated.
6. Apparatus
6.1 Dimension-Measuring Devices—Instruments for measuring length and width shall be checked for accuracy and be graduated
to permit measurements to be made to 60.001 in. (6 0.02 mm) or better.
E517 − 24
6.2 Measuring Devices: Extensometer Systems—
6.1.1 Instruments for measuring length and width shall be checked for accuracy and be graduated to permit measurements to be
made to 60.001 in. (6 0.02 mm) or better.If the axial strain or the transverse strain, or both, are to be obtained using an
extensometer system (mechanical, optical, or otherwise), then the extensometer system shall conform to Practice E83 as Class C
or better, including verification over the range of strains used in the determination of plastic strain ratio, r.
6.1.2 If the longitudinal strain or the transverse strain, or both, are to be obtained using an extensometer, the extensometer system
shall conform to Practice E83 as Class C or better. The extensometer system shall be verified over a range appropriate for the
strains used to determine the plastic strain ratio, r.
6.3 Testing Machine—The testing machine used to strain the specimen shall be capable of uniaxially straining the specimen in
accordance with the requirements in 9.2.5 or 9.3.4.
7. Test Specimen
7.1 Type—Any of three types of specimen may be used. Other types including subsize specimens may be used provided they give
comparable values of equivalent accuracy.
7.1.1 Specimen A, with reduced parallel section, as shown in Fig. 1—While this is similar to the Sheet-Type Specimen of Test
Methods E8/E8M, the reduced parallel section shall be parallel-sided rather than tapered.
7.1.2 Specimen B, with a uniform width of 0.75 in. (20 mm), machined edges, and no reduced section, as shown in Fig. 2.
7.1.3 Specimen C with a uniform width of 1.125 in. (28.58 mm), precision-sheared or with machined edges and no reduced section,
as shown in Fig. 3.
7.2 Size—The length and width of the specimen are not critical, provided care is used to stretch the gauge section in a uniform
manner, avoiding grip effects and anomalous changes along the gauge lengths.
+ gauge mark or extensometer
Dimensions
Specimen B
Standard Alternative
in. mm in. mm
G Gauge length 2.00 ± 0.01 50 ± 0.25 1.00 ± 0.005 25 ± 0.13
W Gauge width 0.75 ± 0.005 20 ± 0.13 0.75 ± 0.005 20 ± 0.13
G Axial gauge 2.00 ± 0.01 50 ± 0.25 1.00 ± 0.005 25 ± 0.1
mark spacing
W Width (Note 1) 0.75 ± 0.005 20 ± 0.13 0.75 ± 0.005 20 ± 0.13
T Thickness
thickness of material
L Overall length, min 8 200 7 175
C Width of specimen 0.75 ± 0.005 20 ± 0.13 0.75 ± 0.005 20 ± 0.13
(Note)
NOTE 1—Edges Longitudinal 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 StripStrip, Specimen B
E517 − 24
+ gauge mark or extensometer
Dimensions
Specimen C
in. mm
G Gauge length 0.75 ± 0.005 20 ± 0.13
G Axial gauge mark spacing 0.75 ± 0.005 19.0 ± 0.1
M Transverse gauge mark spacing 0.75 ± 0.005 19.0 ± 0.1
W Gauge width 0.75 ± 0.005 20 ± 0.13
W Width 1.125 ± 0.125 28.58±3.18
T Thickness thickness of material
L Overall length, min 7 175
C Width of specimen 1.125 ± 0.125 28.58 ± 3.17
FIG. 3 Sheared Rectangular Tension Test Specimen, Parallel
StripStrip, Specimen C
7.2.1 The specimen shall include the full sheet thickness unless otherwise specified.
7.2.2 The thickness of the gauge section of the specimen shall be uniform within 0.0005 in. (0.013 mm) in the gauge section. (0.01
mm). If the as-received surface is nonuniform, the surface shall be prepared by machining or by grinding to this tolerance.
7.2.3 The distance between a gauge mark and a grip grip and either a gauge mark, mechanical extensometer attachment point, or
the pattern/feature to be measured by an optical extensometer system shall be at least twice the width ofspecimen width, theW,
reduced section (or gauge width transverse gauge mark spacing, M, for parallel strips) of the specimen.strips).
NOTE 1—To permit proper gripping of the specimen while meeting the 7.2.3 requirement, the overall length dimension, L, is listed as a minimum, thus
allowing for longer specimens to allow more grip section length.
7.1.4 Duplicate specimens should be tested and the average value of r of these reported for each test direction. If necessary, a third
determination may be made, rejecting the extreme.
7.3 Type—Any Duplicate specimens should be tested and the average value of threer types of specimen may be used. Other types
including subsize specimens may be used provided they give comparable values of equivalent accuracy.of these reported for each
test direction. If necessary, a third determination may be made, rejecting the extreme.
7.2.1 Specimen A, with reduced section, as shown in Fig. 1—While this is similar to Fig. 6 of Test Methods E8/E8M, the reduced
section shall be parallel-sided rather than tapered.
7.2.2 Specimen B, with a uniform width of 0.75 in. (20 mm), machined edges, and no reduced section, as shown in Fig. 2.
7.2.3 Specimen C, precision-sheared a uniform width of 1.125 in. (28.58 mm), or with machined edges and no reduced section,
as shown in Fig. 3.
7.2.3.1 Gauge lengths for Specimen C shall be marked on the sheet surface perpendicular to and parallel to the specimen edges.
The gauge marks shall be made with Vickers diamond indenters described in Test Method E92, or similar precise marks.
8. Specimen Preparation
8.1 Specimen blanks shall be sheared or sawed individually and, with the exception of Specimen C,C which may be used as
sheared, shall be machined individually or in packs to remove cold-worked edges.
E517 − 24
8.2 The dimensions of each specimen shall be measured for uniformity of thickness and width in the gauge section to meet the
requirements of 7.1.27.2.2 and 8.3.
8.3 Within the gauge length, axial gauge mark spacing, parallelism of the edges shall be maintained so that no two width
measurements differ by more than 0.1 % of the measured width (Specimens A and B only).
8.4 Reasonable care shall be taken to position the gauge marks symmetrically to the midpoint and centerline of the specimen or
reduced section.Gauge Marks:
8.4.1 Reasonable care shall be taken to position the gauge marks symmetrically to the midpoint and centerline of the specimen
or reduced parallel section.
8.4.2 Gauge marks for the Manual Procedure (9.2) shall be lightly scribed or punched in the surface of the specimen or made with
a Vickers diamond indenter.indenter described in Test Method E92.
8.4.3 Gauge marks used for an optical extensometer system should be made in a manner appropriate for that system, but the gauge
mark locations used for measurement shall comply with 8.4.1.
8.4.4 For the Automatic Procedure (9.3), mechanical or optical extensometer systems that measure the specimen at the surface
gauge mark locations and meet the requirements of 6.2 may be used.
8.4.5 The gauge lengths mark locations shall comply with 7.1.37.2.3.
8.4.6 For Specimen A, the gauge length axial gauge mark spacing shall be centered in the reduced parallel section.
8.4.7 or Specimen A or B, if the optical extensometer system requires surface marking for transverse strain measurement (that is,
it does not use the edges of the specimen for width measurement), then those transverse gauge marks should be placed as close
as practical to the edges of the specimen width.
8.4.8 For Specimen C, a double set of gauge marks shall be used in compliance with used.7.2.3.1.
8.4.8.1 The measurement of the longitudinal edges of Specimen C, shall not be used for transverse strain measurement.
NOTE 2—Due to the poor quality of the sheared edges, the width is not well defined making it not suitable for transverse strain measurement.
8.4.8.2 The pairs of axial and transverse gauge marks for Specimen C shall be marked on the sheet surface parallel to, and
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