Experimental and Numerical Investigations into Magnetic Pulse Welding of Aluminum Alloy 6016 to Hardened Steel 22MnB5

Rico Drehmann,Verena Kräusel,Sven Winter,Christian Scheffler,Thomas Lampke,Verena Psyk

doi:10.3390/jmmp5030066

Abstract

By means of magnetic pulse welding (MPW), high-quality joints can be produced without some of the disadvantages of conventional welding, such as thermal softening, distortion, and other undesired temperature-induced effects. However, the range of materials that have successfully been joined by MPW is mainly limited to comparatively soft materials such as copper or aluminum. This paper presents an extensive experimental study leading to a process window for the successful MPW of aluminum alloy 6016 (AA6016) to hardened 22MnB5 steel sheets. This window is defined by the impact velocity and impact angle of the AA6016 flyer. These parameters, which are significantly dependent on the initial gap between flyer and target, the charging energy of the pulse power generator, and the lateral position of the flyer in relation to the inductor, were determined by a macroscopic coupled multiphysics simulation in LS-DYNA. The welded samples were mechanically characterized by lap shear tests. Furthermore, the bonding zone was analyzed by optical and scanning electron microscopy including energy-dispersive X-ray spectroscopy as well as nanoindentation. It was found that the samples exhibited a wavy interface and a transition zone consisting of Al-rich intermetallic phases. Samples with comparatively thin and therefore crack-free transition zones showed a 45% higher shear tensile strength resulting in failure in the aluminum base material.

Highlights

Magnetic pulse welding (MPW), which was initially suggested by Lysenko et al in1970 [1], is an innovative technology for manufacturing metallic bonds of similar and dissimilar metals [2]
22MnB5 sheets are often protected by an AlSi anti-scaling coating, which can be assumed to have an influence on the weldability of the material combination
The velocity curve features a plateau of relatively constant velocity, which is followed by a steady decline of the curve

Summary

Introduction

Magnetic pulse welding (MPW), which was initially suggested by Lysenko et al in1970 [1], is an innovative technology for manufacturing metallic bonds of similar and dissimilar metals [2]. Magnetic pulse welding (MPW), which was initially suggested by Lysenko et al in. The setup of the process, which is based on the electromagnetic forming technique [3], consists of the pulsed power generator, the inductor (i.e., the tool), the workpieces to be joined to each other, and additional elements, ensuring that the workpieces are positioned with a defined small gap between them. The pulsed power generator provides storage and a quick release of energy. The inductor typically consists of a winding, which is embedded in an insulating and reinforcing housing material. Inductor winding and fieldshaper are typically made of a material of high electrical conductivity and acceptable mechanical strength such as CuCrZr or CuBe alloys [6]. The same machines and very similar tools can be used for MPW, for electromagnetic forming [3], for electromagnetic

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