A Numerical Study on Co-Extrusion to Produce Coaxial Aluminum-Steel Compounds with Longitudinal Weld Seams

Abstract

The use of lightweight materials is one possibility to limit the weight of vehicles and to reduce CO2 emissions. However, the mechanical properties and weight-saving potential of mono-materials are limited. Material compounds can overcome this challenge by combining the advantages of different materials in one component. Lateral angular co-extrusion (LACE) allows the production of coaxial semi-finished products consisting of aluminum and steel. In this study, a finite element model of the LACE process was built up and validated by experimental investigations. A high degree of agreement between the calculated and experimentally determined forces, temperatures, and the geometrical shape of the hybrid profiles was achieved. In order to determine suitable parameters for further extrusion experiments, the influence of different process parameters on material flow and extrusion force was investigated in a numerical parametric study. Both the temperature and extrusion ratio showed a significant influence on the occurring maximum extrusion force as well as the material flow inside the LACE tool. The maximum force of 2.5 MN of the employed extrusion press was not exceeded. An uneven material flow was observed in the welding chamber, leading to an asymmetric position of the steel rod in the aluminum matrix.

Numerical investigations regarding a novel process chain for the production of a hybrid bearing bushing

“…The differences between the predicted and measured force-time curves in the beginning are caused by the neglected elastic deformation of the tooling in the numerical simulation as well as the variation of the ram speed in the experimental investigations due to a higher ram speed during the filling of the tool. In addition, a good agreement between the measured and calculated temperature curves of the steel rod is presented in [18].…”

“…The compound profiles were extruded at a ram speed of 0.5 mm/s, 2 mm/s as well as 4 mm/s on a 2.5 MN laboratory extrusion press (Müller Engineering). The tool design and the detailed experimental procedure for a ram speed of 0.5 mm/s are described in [18]. The tools and the extrusion billet were preheated to 500 °C and the temperature of the steel rod equalled the room temperature at the beginning of the experiment.…”

“…Tetrahedronal volume elements of a linear interpolation type, which are typical for metal forming simulations were used with a minimum element edge length of 0.28 mm. The influence of the minimal element edge length on the accuracy of the predicted extrusion force and computation time were investigated and described in a previous work by the authors [18]. A periodic initiated remeshing criterion and an automatic size criterion were used for remeshing due to the intensive plastic deformation during the redirection and extrusion within the LACE process.…”

“…Fig. 2 a Comparison between the predicted and measured force-time curves and FE-model set-up [18], b Implementation of the phenomenological model in the FE simulation Induction heating simulations (magnetodynamic-thermal coupled analyses) were conducted using Marc Mentat (MSC Software), a general purpose FE analysis software. Due to the axisymmetric semi-finished workpiece, the model was reduced to two dimensions.…”

Effect of Welding Current on Weld Formation, Microstructure, and Mechanical Properties in Resistance Spot Welding of CR590T/340Y Galvanized Dual Phase Steel

“…In the automotive field, reducing the body weight is one of the most fundamental ways to save energy and reduce pollution. Therefore, more and more lightweight and high-strength materials have been developed for body manufacturing [1,2,3]. Galvanized dual phase steel has the advantages of low yield ratio, good formability, high tensile strength, good matching of strength and plasticity, corrosion resistance, and so on, which has been used in automobile body manufacturing [4,5,6].…”