Investigation of the stress-strain state of balls under deformation in a closed die

Abstract

The paper presents the results of the study of the production process of balls in a special closed die, which performs a full compression due to the alternate insertion of rams. The possibility of implementing the proposed method is proved experimentally, and the presence of high compressive stresses in the deformation center is shown using the method of sliding lines and mathematical computer modeling. Due to the alternate insertion of rams, the process of plastic deformation is intensified, which makes it possible to obtain high-quality balls. The maximum average stress in the deformation center obtained by the theoretical calculation method of sliding lines is – 436,94 MPa, and the values obtained by mathematical computer modeling is – 500 MPa. Metallographic analysis showed that the grain diameter of the obtained ball samples in the central part, compared to the initial samples, was crushed 3 times (up to 5 μm).

Keywords

• high strength ball
• forging
• severe plastic deformation
• stress-strain state
• closed die
• modelling