Microstructural analysis of sheet hydroforming process assisted by radial ultrasonic punch vibration in a hydro-mechanical deep drawing die

Abstract

Today, the use of sheet hydroforming methods in the conventional deep drawing process has signi cantly improved the formability of the sheet. However, due to the limitations of the sheet hydroforming process, new methods can be used in combination with it, such as ultrasonic-vibrationassisted forming. Many of the mechanical effects of ultrasonic vibration in the metal forming process are due to the metallurgical and structural impacts of the material, so to nd the cause of the observed events, one must look at the microstructural interactions of materials. Therefore, the process of St14 sheet hydroforming with the assistance of ultrasonic vibration is investigated microstructurally in this paper. For this purpose, during the hydroforming drawing process, ultrasonic vibration was radially applied to the punch in a hydro-mechanical deep drawing die. Then the process parameters, including thickness, equivalent strain, grain size, and rotation at a selected point of the cross-section of the sample parts are compared in four modes of conventional deep drawing (CDD), hydroforming deep drawing (HDD), deep drawing assisted by ultrasonic vibration (UDD), and hydroforming deep drawing assisted by ultrasonic vibration (UHDD). Results showed that the application of ultrasonic vibrations in the sheet hydroforming process led to a signi cant reduction in thickness strain (as well as equivalent strain), increased grain length, and reduced rotation. This implies the positive impact of ultrasonic vibrations in the ow of materials is due to the reduction of friction and facilitates the movement of dislocations.

On Improving Sheet Metal Formability in Hydrodynamic Deep Drawing Process through a Solid‐Oil‐Type Mineral Grease Pressure Medium

“…In the past two decades, several scholars employed different variations of the hydroforming process, all aimed at increasing accuracy and reducing forming defects, among them the hydromechanical deep drawing, [8,9] hydrodynamic deep drawing (HDDD), [5,10] and HDDD assisted by radial pressure (HDDRP). [11,12] Concerning the HDDRP process, the application of a radial pressure leads to remarkable advantages in terms of drawing ratio and low thinning.…”

Improvement of Formability of AISI 1006 Sheets by Hydroforming with Die in Square Deep Drawing

“…As a result, new manufacturing technologies have been developed and improved. One of the developed technologies and the most important sheet-forming processes is a Sheet Hydro-Forming (SHF) process [6,7].…”