【国外标准】 Standard Test Method for Bend Test for Determining the Formability of Copper and Copper Alloy Strip

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.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.