Method and apparatus for bonding metal plates and hot strip rolling mill

In an apparatus for bonding metal plates, an upper shear blade (3) having a projection (30) in the form of a triangular column, and a lower shearing blade (4) having a projection (40) having the same shape, to the overlapping portion of the metal to be joined panels (1, 2) is applied and then pressed in the metal plates in an inclined with respect to the thickness direction, oblique direction by a stroke which is dimensioned so that the metal plates are not cut through completely. The operating loci of the upper shearing blade and the lower shearing blade overlap. The sheared surfaces of the metal plates form a connecting portion by deformation by plastic flow. As a compressive force is applied to the portions to be joined, the area defined by the amount of overlap portion and the portions to be joined are compressed to form a compressed portion after completion of the joining, whereby the joint strength is increased. In addition, since the projections on the circuit boards generate a pressing force pressing the sheared surfaces against each other takes through the effect of their inclined surfaces the compressive force exerted on the connecting portion to pass.