On the basis of geometric numeration in explosive welding, the collision angle and the velocity of the collision point, which are joining parameters, in magnetic pulse welding were obtained by free deformation analysis without collision deformation analysis. The collision angle and the velocity of the collision point on a joining region in a welded sheet were found by comparing positions of them with the joining region in the welded sheet. The study demonstrated the effect of gap length on the joining parameters and a joining process，resulting in the convex deformation of the A1050-H24 moving sheet and the removal of a metal jet. In the joining region, the range of collision angles is from 2.6° to 31.3° and the range of velocities of the collision point is from 7.5 km∙s-1 to 0.48 km∙s-1. The small collision angle and the high velocity of the collision point depend on the plastic hinge appearing at the early stage in the convex deformation of the moving sheet. It has been clarified that the joining parameters can be calculated by incorporating geometric numeration into the convex shape of the moving sheet.
