The experimental investigation of springback of s235jr sheet metals within bending die

The bending process is one of the important process in sheet metal processings. Obtaining the product with desired angles in bending processes is very important. In order to obtain the desired angle value on the bent part, it is necessary to know the values of springback on springforward.In this experimental study, firstly, 30º, 60º and 90º bending processes were caried out for S235JR materials with diffrent thicknesses (3, 4, 5 and 6 mm). The materials which were cold, tempered and normalized were bent for each angle and thickness. Moreover, bending processes were performed without waiting and with waiting the punch on the part 30 s Secondly, S235JR materials with 4 mm thickness were bent with five different punch radius. Moreover, materials which were cold, tempered and normalized were bent for 90º bending process. Thirdly, S235JR materials with 4 mm thickness were tempered in 30 min. After bending these materials with a punch having 6 mm radius, the differences between springback and springforward values were investigated.At the end of the experiments, When tempering time of S235JR sheet metal increased, ideal bending angle was obtained. It was determined that normalisation process increased springforward for all thicknesses and bending angles. Bending process were performed with punches having different and radius. When punch and radius increased, the springforward value decreased for S235JR material. When sheet metal thickness increased at the 30º bending process, was increased springforward values. In the 60º and 90º bending processing, When sheet metal thickness enhanced, springforward values decreasing was determined according to experimental results.