Forming Limit Extension of High-Strength Steels in Bending Processes

Abstract

Bending is a commonly used forming technology in metal forming. The occurring springback and low forming limits of high-strength steels especially during air bending are the main disadvantages. In this paper, the conventional air bending process is applied with a hydrostatic pressure in the bending zone. This was done using an elastomer tool. The advantage of this method is that the flexibility of air bending is maintained by reducing the springback while the forming limits are extended. Furthermore, different geometries for the elastomer tool were investigated by means of a FEM simulation. The investigation leads to a reduction of the process forces by minimizing the springback and to an extension of the forming limits.

Analysis of the Potential of Incremental Stress Superposition on Air Bending

“…The influence of the elastomer hardness was exemplarily investigated during the manufacturing of a rear suspension of a car [11]. More recent studies deal with the creation of an analytical model to predict the springback [12] and the expansion of the forming limits [13].…”

Metal forming beyond shaping: Predicting and setting product properties

“…On the basis of this principle, an adjustment of the hardness of the elastomer counterholder is possible in order to control the superimposed stresses and to avoid crack occurence [36].…”