ASTM B820-23
(Test Method)Standard Test Method for Bend Test for Determining the Formability of Copper and Copper Alloy Strip
Standard Test Method for Bend Test for Determining the Formability of Copper and Copper Alloy Strip
SIGNIFICANCE AND USE
5.1 This bend test provides information as to the formability or the ability of copper and copper alloy strip to resist cracking when being formed.
5.2 This test method can be used as a quality control tool to determine if material will form to a given radius.
5.3 This test method is also useful in research and development to provide data for use in selecting a spring material that will safely form to the geometry of a given part.
5.3.1 The forming characteristic of interest is the smallest bend radius that can be formed without cracks or otherwise unacceptable surface conditions (8.4). This radius, R, is the radius of curvature of the nose of the punch used in the test.
5.3.2 In addition, the difference between the angle of the bend after testing and 90° provides a measure of post-forming springback.
5.4 The results are suitable for direct application in design and manufacturing, only when all factors such as the geometry of the part, punch and die design, lubrication, stamping speed, and other material properties are known.
SCOPE
1.1 This test method covers the technique of bend testing copper and copper alloy strip samples to determine product formability or the ability to resist cracking when forming a bend around a specific radius. The criterion for failure is the occurrence of cracks on the convex surface of the bend.
1.2 This bend test is limited to strip from 0.003 in. to and including 0.031 in. (0.076 mm to and including 0.79 mm) thick.
1.3 The forming or punch radius for the bend test shall be determined by agreement between the manufacturer or supplier and purchaser. This punch radius is typically equal to or greater than the minimum bend radius without failure for the alloy, temper and thickness combination of the strip being tested.
1.4 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units which are provided for information only and are not considered standard.
1.5 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.
1.6 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.
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Standards Content (Sample)
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.
Designation: B820 − 23
Standard Test Method for
Bend Test for Determining the Formability of Copper and
1
Copper Alloy Strip
This standard is issued under the fixed designation B820; 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* 2. Referenced Documents
2
2.1 ASTM Standards:
1.1 This test method covers the technique of bend testing
B846 Terminology for Copper and Copper Alloys
copper and copper alloy strip samples to determine product
E6 Terminology Relating to Methods of Mechanical Testing
formability or the ability to resist cracking when forming a
E290 Test Methods for Bend Testing of Material for Ductil-
bend around a specific radius. The criterion for failure is the
ity
occurrence of cracks on the convex surface of the bend.
3. Terminology
1.2 This bend test is limited to strip from 0.003 in. to and
including 0.031 in. (0.076 mm to and including 0.79 mm)
3.1 For definitions of terms related to copper and copper
thick. alloys, refer to Terminology B846.
3.2 For definitions of terms related to mechanical testing,
1.3 The forming or punch radius for the bend test shall be
refer to Terminology E6.
determined by agreement between the manufacturer or supplier
and purchaser. This punch radius is typically equal to or greater
3.3 Definitions of Terms Specific to This Standard:
than the minimum bend radius without failure for the alloy,
3.3.1 bend, longitudinal (or good way bend)—a bend with
temper and thickness combination of the strip being tested. an axis perpendicular to the direction of rolling, drawing, or
extrusion (see Fig. 1).
1.4 Units—The values stated in inch-pound units are to be
3.3.2 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 which are provided for
extrusion (see Fig. 1).
information only and are not considered standard.
NOTE 1—The usage of these two terms is consistent with Test Methods
1.5 This standard does not purport to address all of the
E290.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 4. Summary of Test Method
priate safety, health, and environmental practices and deter-
4.1 The bend test is made by applying a force transversely
mine the applicability of regulatory limitations prior to use.
to the length of the specimen in the portion being bent, usually
1.6 This international standard was developed in accor- at mid-length. The 90° bending forces are applied through an
dance with internationally recognized principles on standard-
arrangement illustrated in Fig. 2, while 180° bending forces are
ization established in the Decision on Principles for the applied through an arrangement illustrated in Fig. 3. When
Development of International Standards, Guides and Recom- complete fracture does not occur, the convex surface of the
specimen is examined for cracks. In general, the test using a
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee. 180° bend angle is a more severe test than the test using a 90°
bend angle.
5. Significance and Use
5.1 This bend test provides information as to the formability
or the ability of copper and copper alloy strip to resist cracking
when being formed.
1
This test method is under the jurisdiction of ASTM Committee B05 on Copper
and Copper Alloys and is the direct responsibility of Subcommittee B05.06 on
2
Methods of Test. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2023. Published November 2023. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1992. Last previous edition approved in 2018 as B820 – 18. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/B0820-23. 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
1
---------------------- Page: 1 ----------------------
B820 − 23
die. A punch of a given bend radius applies the bending force
at the specimen mid-length.
6.1.2 180° Bend Test Fixture—An illustration of this test
fixture is shown in Fig. 3. A specimen rests on a pair of pins,
rollers, or radiused flat sup
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: B820 − 18 B820 − 23
Standard Test Method for
Bend Test for Determining the Formability of Copper and
1
Copper Alloy Strip
This standard is issued under the fixed designation B820; 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 describescovers the technique of bend testing copper and copper alloy strip samples to determine product
formability or the ability to resist cracking when forming a bend around a specific radius. The criterion for failure is the occurrence
of cracks on the outer (convex) radius of curvature.convex surface of the bend.
1.2 This bend test is limited to strip from 0.0030.003 in. to and including 0.031 in. (0.076(0.076 mm to and including 0.79 mm)
thick.
1.3 The forming or punch radius for the bend test is to shall be determined by agreement between the producer and the
customer.manufacturer or supplier and purchaser. This punch radius is typically equal to or greater than the minimum bend radius
without failure for the alloy, temper and thickness combination of the strip being tested.
1.4 Units—Values The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are
mathematical conversions to SI units which are provided for information only and are not considered standard.
1.5 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.
1.6 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
2.1 ASTM Standards:
B846 Terminology for Copper and Copper Alloys
E6 Terminology Relating to Methods of Mechanical Testing
E290 Test Methods for Bend Testing of Material for Ductility
3. Terminology
3.1 For definitions of terms related to copper and copper alloys, refer to Terminology B846.
1
This test method is under the jurisdiction of ASTM Committee B05 on Copper and Copper Alloys and is the direct responsibility of Subcommittee B05.06 on Methods
of Test.
Current edition approved March 1, 2018Nov. 1, 2023. Published March 2018November 2023. Originally approved in 1992. Last previous edition approved in 20142018
as B820 – 14a.B820 – 18. DOI: 10.1520/B0820-18.10.1520/B0820-23.
2
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
1
---------------------- Page: 1 ----------------------
B820 − 23
3.2 For definitions of terms related to mechanical testing, refer to Terminology E6.
3.3 Definitions of Terms Specific to This Standard:
3.3.1 bend, longitudinal (or good way bend)—a bend with an axis perpendicular to the direction of rolling, drawing, or extrusion
(see Fig. 1).
3.3.2 bend, transverse (or bad way bend)—a bend with an axis on a plane parallel to the direction of rolling, drawing, or extrusion
(see Fig. 1).
NOTE 1—The usage of these two terms is consistent with Test Methods E290.
4. Summary of Test Method
4.1 The bend test is made by applying a force transversely to the length of the specimen in the portion being bent, usually at
mid-length. The 90° bending forces are applied through an arrangement illustrated in Fig. 2, while 180° bending forces are applied
through an arrangement illustrated in Fig. 3. When complete fracture does not occur, the convex surface of the 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° bend angle.
5. Significance and Use
5.1 This bend test provides information as to the formability or the ability of copper and copper alloy strip to resis
...
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