Springback reduction in U-Channels—“double-bend” technique

Abstract

The walls of a U-channel may be slanted, either because of the consequence of a previous forming operation or simply because of springback. The resulting wall inclination can be reduced if the U-channel is unbent and bent again at a new site—the “double-bend” technique. Based on this simple, geometric concept, five practical methods—three restrike and two forming operations—have been advanced and experimentally shown capable of significantly reducing the wall inclination or springback in steel U-channels. In some specific cases, process variables which affect springback in the double-bend technique are just the opposite of those used in practice.