Probing magnetic pulse welding of aluminium and steel sheets

Analytical Estimation of Electromagnetic Pressure, Flyer Impact Velocity, and Welded Joint Length in Magnetic Pulse Welding

“…Figure 3b shows that the analytically calculated values of the EM pressure for MPW of sheets using Equation (19). For example, the analytically computed EM pressures for MPW of AA5754 and DC04 steel sheets [2] using a linear coil with a rectangular cross-section are found to be 139 and 223 Mpa for a discharge energy of 10 and 16 kJ, respectively. The corresponding numerically calculated values are 85 and 118 Mpa, respectively [2].…”

“…A dimensional analysis using the Buckingham π-theorem is therefore undertaken to develop a relationship for EM pressure as a function of the important variables [46]. Since the MPW of tubes and sheets uses, respectively, circular and flat coils with different geometry and a different effective cross-sectional area, the relationships for the corresponding EM pressure are developed separately [2,7]. Table 1 presents ten variables and their dimensions in the MLTI system, which are considered for the dimensional analysis of EM pressure for MPW of tubes.…”

“…The joint length is referred to the intimate contact along the flyer-target interface as a result of the EM pressure of the flyer, its progressive impact on the target and the consequent visco-plastic deformation of the flyer-target assembly [3,5]. The joint length is often observed using microscopy and measured by means of peel tests [2,7,33]. The finite element method based computational models for MPW have construed the joint length by examining the segment of the flyer that is in close contact with the target along the flyertarget interface [2,5,7].…”

“…The joint length is often observed using microscopy and measured by means of peel tests [2,7,33]. The finite element method based computational models for MPW have construed the joint length by examining the segment of the flyer that is in close contact with the target along the flyertarget interface [2,5,7]. It is therefore quite difficult, or even impossible, to identify the exact length of the joint for MPW of tubes and sheets and the difficulty is exacerbated further due to the microscopic wavy nature of the joint interface [10,14].…”

“…The resulting EM force drives the flyer part to impact on the target part, with high velocity, leading to rupture and jetting of the surface impurities and rapid coalescence between the overlapped parts [1]. An advance estimate of the EM pressure and the flyer impact velocity is required to design a suitable process schedule and to assess the joint quality in MPW [2]. The use of comprehensive numerical models [3] and wide-ranging experiments [4] is growing, to improve the insightful understanding of MPW, but these are computationally intensive [5] and time-consuming [6].…”