Investigation On Magnetic Pulse Cladding Of3A21Aluminum-steel20Tubes

Bi-metal tubes which combine the excellent property of two different metalshave the advantages of saving precious metals, reducing costs and expandingfunctionality compared to the metal tube consisting of single group material,whichresults in its broad prospect of application in modern industry. A novel process ofmanufacturing bi-metal tube,called magnetitc pulse cladding(MPC), is presented.Both numerical and experimental investigation are carried out to study the plasticdeformation of outer tube(covered tube) during the MPC process, the features of thecombination rigion as well as the effect of the process parameters on the bondingquality.The results by the FEA of MPC in tube compression processing model based onANSYS software show that: the plastic deformation of the outer tube contains thetube compression and the transition region compression which involves thetransformation from bending state back to straight state. In the case of fieldshaperwith constant cross sections, the axial plastic deformation of the transition region isrestrained by the compression of the priority part, which leads to―convex‖, thematerial accumulation on the surface of the bi-metal tube. With the decreasing of thefeeding length or increasing the discharging voltage, the amplitude of―convex‖reduces. Fieldshaper with variable cross sections improves the distribution of themagnetic pressure, which lowers relatively the amplitude of―convex‖in themagnitude of47%.MPC on20#steel/3A21aluminum tubes was investigated experimentally,employing peel test and compression shear test respectively to detect the adhesionproperty. The results show that mechanical bonding take place in the feeding lengthless than the one of transition region due to the weak collision while themetallurgical bonding in the width of2mm appears in the feeding length betweenlength of transition zone and the one of fieldshaper work zone.The relativeconcentrated bonding zone in the width about47%of the combinatin zone appearsin the case of filedshaper with variable cross sections,10kV discharging and2.0mmradial gap.The shear strength in the bonding zone distribute ununiformly and themaximun appears.With the increasing of the discharging energy, the maximun shearstrength increases accordingly first then down. The maximum shear strength79.2MPa has been got in the case of15kV discharging voltage,2.0mm workpiece radialgap,fieldshaper with variable cross sections.Morphology analysis reveals that the combination region features alternatelyflat interface and a wavy or rippled pattern interface which relates to combination region with high shear strength. The grain refinement was observed in the waveinterface where the grains in20#steel body were stretched into flow line.Intermediate layers with different width diffusion in the phase of layer or lump weredetected by the energy spectrum analysis (by linear scan) of Al, Fe elementsdistribution,which indicates that the bi-metal tube has been got metallurgicalbonding locally.