Papers by Author: Pablo Barreiro

Abstract: Electromagnetic compression of tubular profiles with high electrical conductivity is an innovative joining process for lightweight structures. The components are joint using pulsed magnetic fields which apply radial pressures of up to 200 MPa to tubular work pieces causing a symmetric reduction of the diameter with typical strain rates of about 104 sec-1. Since there is no contact between the components to be joined and the joining machine, any damage of component’s surface can be avoided. Friction stir welding (FSW) is a relatively new solid state joining technique and has been extensively developed for aluminum, magnesium, copper and titanium alloys as well as steels. The primal advantages of the process in comparison to conventional fusion welding are better mechanical properties, low residual stresses and distortion, and reduced occurrence of defects. In the present article, the influence of process and material parameters on the joint’s characteristics, material’s microstructure and the mechanical properties of electromagnetic compressed joints and friction stir welds using reinforced aluminum profiles is analyzed. The strength of the joint is determined by tensile tests. Finally, possible improvements of both techniques are outlined.

Abstract: Electromagnetic compression of tubular profiles with high electrical conductivity is an innovative joining process for lightweight structures. The components are joint using pulsed magnetic fields which apply radial pressures of up to 200 MPa to tubular work pieces causing a symmetric reduction of the diameter with typical strain rates of about 104 sec-1. Since there is no contact between components to be joined and the joining machine, any damage of component’s surface can be avoided. The load, which the joint can transmit, is strongly dependent on the residual stresses in the region of the joint. In the present article, the influence of charging energy, gap width before joining and diameter on the development of the residual stresses is analysed using geometry changes during splitting of the components. Besides, the contact zone between the components is analysed and the pullout force of the joints is determined by tensile tests. This allows the evaluation of correlations between joining process, state after joining and mechanical properties.

Abstract: Electromagnetic Compression of tubular profiles with high electrical conductivity is an innovative joining process for light weight structures. The components are joined using pulsed magnetic fields which apply radial pressures of up to 200 MPa to tubular work pieces causing a symmetric reduction of the diameter with typical strain rates of about 104 sec-1. This process avoids any surface’s damage of the workpiece because there is no contact between the components and the forming tool. The load, which the joints can transmit, strongly depends on the process parameters. Of them, the charging energy and initial gap between components are the most important. In the present article, the influence of these two parameters on the joint’s characteristics, material’s microstructure and the mechanical properties is analyzed. The strength of the joint is determined by tensile tests and by measurements of the residual stresses. Finally, conclusions for the joint design are given.