New Applications of Non-Destructive Testing in Metal Forming Technology

Abstract

In forming technology non-destructive testing (NDT) methods are already quite established in basic and industrial research as well as in practice. Due to the continually enhanced capabilities of these methods, new fields of application can be expected in future. In this paper recent developments in experimental and evaluation techniques for three such new applications are presented. The first is the ultrasonic in situ inspection of the real contact area (RCA) between billet and tool in upsetting. It is demonstrated that the evolution of the RCA during the forming process can be measured with high lateral resolution and good reproducibility. The second application deals with the examination of the state of pre-stressing of extrusion dies reinforced by a stress ring. Again the ultrasonic method is applied and is shown to be suited to give detailed information about the conformity of the reinforcement. Finally, the well-known method of material characterization based on the magneto-inductive principle is adapted to the task of on-line quality control in sheet metal forming. The applicability and efficiency of this method are verified by experimental results.