Abstract
It is known that curved hat channel product of high strength steel sheet has severe springback, twist. This paper presents the above mentioned defective phenomenon in two kinds of curved hat channel product of high strength steel sheet; one (2-dimensional part) has curvature on the horizontal plane, and the other (3-dimesnional part) has furthermore curvature on the vertical plane. After slitting on the wall of the products, difference in the phenomenon is investigated. Therefore, it is confirmed that the twist of product in the longitudinal direction is mainly caused by the influence of punch edge springback.
