Bending process is one of the most significant fields of application of sheet metal die. Sheet metals are ex posed to some spring back or spring-forward depending on elastic deformation following bending process. S235...Bending process is one of the most significant fields of application of sheet metal die. Sheet metals are ex posed to some spring back or spring-forward depending on elastic deformation following bending process. S235JR （1. 003 8） materials having a thickness of 4 mm were bent with 90° punches having 5 different tip radiuses. The ben- ding process was carried out by making the punch waited on the material for 30 s （30 s wait bending） and by remo ving the punch without waiting （direct bending）. Specimens were prepared in three forms as non-heat-treated, nor- malized and tempered. At the same time, all experiments were performed at a deformation speed of 25 mm/min. As a result, it was determined that as punch tip radius increased, the amount of spring-forward decreased. Although normalizing process applied to specimens increased the amount of spring-forward, tempering process decreased it. The amount of spring-forward was decreased in 30 s wait bending process.展开更多
文摘Bending process is one of the most significant fields of application of sheet metal die. Sheet metals are ex posed to some spring back or spring-forward depending on elastic deformation following bending process. S235JR （1. 003 8） materials having a thickness of 4 mm were bent with 90° punches having 5 different tip radiuses. The ben- ding process was carried out by making the punch waited on the material for 30 s （30 s wait bending） and by remo ving the punch without waiting （direct bending）. Specimens were prepared in three forms as non-heat-treated, nor- malized and tempered. At the same time, all experiments were performed at a deformation speed of 25 mm/min. As a result, it was determined that as punch tip radius increased, the amount of spring-forward decreased. Although normalizing process applied to specimens increased the amount of spring-forward, tempering process decreased it. The amount of spring-forward was decreased in 30 s wait bending process.
