Simulation Assisted Process Development for Tailored Forming

Abstract

Transport industry faces challenges steadily due to rising fuel costs and stricter regulations for the emission of air pollutants. Technological developments that reduce fuel consumption are necessary for sustainable and resource-efficient transport. Innovative production technologies utilising multi-material designs come to the fore in an attempt to fabricate lightweight products with extended functionality. Departing from this motivation, novel process chain concepts for the manufacturing of bi-material forged products are being researched at the Leibniz Universität Hannover in the context of the Collaborative Research Centre (CRC) 1153. The developed technology is referred as Tailored Forming and deals with the deformation and subsequent processing of joined hybrid workpieces to produce application-oriented products. Deformation processes are carried out at elevated temperatures for thermomechanical treatment of the joining zone properties. Researchers make use of numerical simulation in each step in the process chains. This paper explains the challenges associated with induction heating and impact extrusion of bi-material forging billets and presents our solution approaches with the aid of numerical modelling. Experimental validation results and analysis of deformed workpieces are also shown.

Enhancement of the interface of friction welded steel-aluminium joints

“…By superimposing counter Fig. 3 Steel-aluminium joining zone after extrusion (a) and the central micrographs: (b) without counter pressure superposition; (c) with counter pressure superposition [15] pressure, however, the stress state could be controlled which led to the elimination of cracks.…”

Contact Geometry Modification of Friction-Welded Semi-Finished Products to Improve the Bonding of Hybrid Components

“…Hence, an inhomogeneous temperature distribution in the joined parts prior to the forming has to be ensured to align the flow curves of the investigated 20MnCr5 steel and of the AA6082 aluminum alloy (EN AW-6082). Therefore, a customized inductive heating strategy was developed to achieve the material-specific forming temperatures of 900 • C in steel and 20 • C in aluminum simultaneously [7].…”

“…Hence, an inhomogeneous temperature distribution in the joined parts prior to the forming has to be ensured to align the flow curves of the investigated 20MnCr5 steel and of the AA6082 aluminum alloy (EN AW-6082). Therefore, a customized inductive heating strategy was developed to achieve the material-specific forming temperatures of 900 °C in steel and 20 °C in aluminum simultaneously [7]. Friction welding was selected based on various reports which concluded that the successful joining of aluminum alloys and steels and the free designability of joining zone geometry-e.g., Ashfaq et al detected an increased bond strength when using a conical geometry instead of flat surface.…”

Applying Membrane Mode Enhanced Cohesive Zone Elements on Tailored Forming Components

“…Subsequent heat treatments cause thickening of intermetallic compounds to about 2 µm [2]. Though practical investigations indicate advantages of joining zones without or with a non-measurable intermetallic compound thickness during forming [3].…”