ASTM B820-04e1

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e1
Designation: B 820 – 04
Standard Test Method for
Bend Test for Determining the Formability of Copper and
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Copper Alloy Strip
This standard is issued under the fixed designation B 820; 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.
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e NOTE—An editorial change was made to subsection 1.3 in October 2004.
1. Scope* E 290 TestMethodforSemi-GuidedBendTestforDuctility
of Metallic Materials
1.1 This test method describes the technique of bend testing
copper and copper alloy strip samples to determine product
3. Terminology
formability or the ability to resist cracking when forming a
3.1 Definitions—For definitions of terms related to copper
bend around a specific radius. The criterion for failure is the
and copper alloys, refer to Terminology B 846, and for
occurrence of cracks on the outer radius of curvature (convex).
definitions of terms relating to mechanical testing, refer to
1.2 This bend test is limited to strip from 0.003 to and
Terminology E 6.
including 0.031 in. thick. (0.076 to and including 0.79 mm).
3.2 Description of Terms Specific to This Standard:
1.3 The size of the forming radii used in this test shall be
3.2.1 bend, longitudinal (or good way bend)—a bend with
0.005 to and including 0.250 in. (0.127 to and including 6.35
an axis perpendicular to the direction of rolling, drawing or
mm).
extrusion (see Fig. 1).
1.4 Units—The values stated in inch-pounds are to be
3.2.2 bend, transverse (or bad way bend)—a bend with an
regarded as standard. The values given in parentheses are
axis on a plane parallel to the direction of rolling, drawing or
mathematical conversions to SI units that are provided for
extrusion (see Fig. 1).
information only and are not considered standard.
1.5 This standard does not purport to address all of the
NOTE 1—The usage of these two terms is consistent with Test Method
safety concerns, if any, associated with its use. It is the E 290.
responsibility of the user of this standard to establish appro-
4. Summary of Test Method
priate safety and health practices and determine the applica-
4.1 The bend test is made by applying a force transversely
bility of regulatory limitations prior to use.
to the length of the specimen in the portion being bent, usually
2. Referenced Documents
at midlength. The 90° bending forces are applied through an
arrangementillustratedinFig.2,while180°bendingforcesare
2.1 The following documents in the current issue of the
BookofStandardsformapartofthisspecificationtotheextent applied through an arrangement illustrated in Fig. 3. When
complete fracture does not occur, the convex surface of the
referenced herein:
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2.2 ASTM Standards: specimen is examined for cracks. In general, the test using a
180° bend angle is a more severe test than the test using a 90°
B 846 Terminology for Copper and Copper Alloys
E 6 Terminology Relating to Methods of Mechanical Test- bend angle.
ing
5. Significance and Use
5.1 This bend test provides information as to the formability
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This test method is under the jurisdiction ofASTM Committee B05 on Copper
or the ability of copper and copper alloy strip to resist cracking
and Copper Alloys and is the direct responsibility of Subcommittee B05.06 on
when being formed.
Methods of Test.
5.2 This test method can be used as a quality control tool to
Current edition approved May 1, 2004. Published May 2004. Originally
approved in 1992. Last previous edition approved in 1998 as B 820 – 98.
determine if material will form to a given radius.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.3 This test method is also useful in research and develop-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
ment to provide data for use in selecting a spring material that
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. will safely form to the geometry of a given part.
*A Summary of Changes section appears at the end of this standard.
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e1
B820–04
6.3 The length of all pins, rolls, mandrels, and radius flats
must exceed the width of the specimen; they must be strong
enough and sufficiently rigid to resist significant deformation.
7. Test Specimens
7.1 Five specimens are required for this test.
FIG. 1 Direction of Bending
7.2 The test specimens may be prepared by cutting, shear-
ing, or stamping.
1 1
7.3 The test specimens shall have a width of ⁄2 6 ⁄16 in.
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(12.7 6 1.57 mm)
...