ASTM B820-09

This bend test provides information as to the formability or the ability of copper and copper alloy strip to resist cracking when being formed.

This test method can be used as a quality control tool to determine if material will form to a given radius.

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.

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.

1.1 This test method describes 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 radius of curvature (convex).

1.2 This bend test is limited to strip from 0.003 to and including 0.031 in. thick. (0.076 to and including 0.79 mm).

1.3 The size of the forming radii used in this test shall be 0.005 to and including 0.250 in. (0.127 to and including 6.35 mm).

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 that 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 and health practices and determine the applicability of regulatory limitations prior to use.