Not only good mechanical properties but also good bend ductility are required for the use of copperalloy to small-sized electronic components. Relation between reduction of cold rolling and minimumbending radius were studied analytically and experimentally. True strain by light cold roll reductionand bending are presumed to be able to added to each other under the condition that practically shearbands are not active by rolling. Minimum bending radius under 90°L bending were determined withseveral reduction ratio for C26800 and C14410. The strain limit, which was calculated from theconditions at the minimum radius bend, was proved to be peculiar to each copper alloy. Wrinkles bybending were studied micrographically. In bending, shear band deformation is localized and slipbands at the localized site appear as a small dent in cross section. The size of the dent was discussedin relation to decision of minimum bending radius.
展开▼
