The effect of die and blank holder geometry on the hardness of sheet metal formed by the stamping process

• Main Authors: Jabar, Mohammed M., Mohammed, Adnan I.
• Format: Conference Proceeding
• Language: English
• Subjects: Angles (geometry); Blankholders; Blanking; Cold stamping; Cold working; Dies; Geometry; Hardness; Mechanical properties; Metal forming; Metal sheets; Rolling direction; Stainless steels; Stamping
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0205992

One of the most fundamental processes for forming sheet metal is the stamping-drawing process, which is used in the manufacture of auto parts. The goal of this paper is to investigate the effects of die geometry, blank holder geometry, and rolling direction (0o, 45o, and 90o) on a few mechanical properties such as the distribution of hardness in the drawing part cup sections (flange, wall, and bottom) product by the stamping-drawing process of cold working in sheet metal forming. A three-dimensional (3D) shape of a circular cup, including an external diameter of 50 mm, a 10 mm height, and a thickness of 1 mm, has been created. To produce this cup, stainless steel (416) according to ASTM specifications was selected and two different types of dies and blank holders were used: flat die/flat blank holder with an angle of 0° and slop die/slop blank holder at an angle of 15° to increase the flow of the metal and reduce the hardness. The die profile radius is equal to 6mm and the punch profile radius is equal to 6mm. Through the experiment results obtained from cups produced, it is shown that the values of hardness in cup zones (flange, wall, and bottom) when the forming process is using a slop die are better for reducing the hardness values than when using a flat die. Furthermore, the hardness decreased when forming at an angle of 0°, which is considered better than the 45o and 90o angles, depending on the direction of the rolling.