2007 Volume 48 Issue 555 Pages 323-327
The seam welding described in this paper is particularly effective for dissimilar sheet metals with different conductivities, for example, Al⁄Fe. Because the aluminum sheet with high conductivity is able to obtain sufficient energy from an electric circuit, this sheet is accelerated by a high magnetic pressure and collides with the fixed steel sheet. Both these surfaces can be clarified by the effect of the collision, and then joined with each other by both the magnetic pressure and the joule heat generated in the aluminum sheet. In this method, the steel sheet can also be thick because the sheet is placed on the outside of a welding coil. Therefore, it is possible to weld the aluminum sheet to a flat surface on a square pipe of steel or to a tee joint. The effect of a gap between two aluminum sheets (1mm thick each) is examined for comparison with another seam welding method that we have reported. The collision velocity calculated from the collision time becomes half of that obtained by another method but is more than 100 m⁄s, and the welded sheet has a large shearing tensile strength. The bank energy required for welding a 5×50 mm2 area is about 1 kJ by generating the gap between the two aluminum sheets.
