The influence of the rolling direction on the elastic characteristics of the bending samples

There are a number of factors influencing the bending process such as: the rolling direction of the blank; the minimum bend radius of the piece; the radii of the bending plate (of the mold); the play between the die and the punch, the recoverable strain of the piece after bending. The paper presents the experimental results regarding the influence of the lamination direction on the rheological behaviour of the cold bending parts, using the Lloyd LS100 Plus universal machine and the Nexygen Plus program. Thus, two categories of samples were analyzed: some being cutted off in the direction of rolling of the sheet at which the bending occurred on an axis perpendicular to the direction of rolling and others cutted on cross direction of rolling, the bending being produced along the axis parallel to the rolling direction. As an elasto-plastic process, after the loading process during experiment, the samples recorded an elastic strain recovery due to the kinetic energy stored during stresses. Thus, the recovered elastic deformation (springback) is more pronounced in the case of specimens cutted of in cross direction on the rolling fiber where the bending moment is produced in the direction parallel to the laminating fiber of materials.