49 巻 (2008) 568 号 p. 419-423
Three aluminum alloy and steel sheets were joined with a self-piercing rivet. Self-piercing riveting can be applied to join steel and aluminum alloys having very different melting points because of plastic joining. The requisites for joining the three sheets are the driving of the rivet leg through the middle sheet, the flaring of the rivet leg in the lower sheet and the prevention of the fracture of the lower sheet. The joinability for various combinations of the three sheets was determined. When the thickness of the lower sheet is small and the total thickness is large, the rivet leg cannot be driven through the middle sheet owing to the relatively small length of the rivet leg. On the other hand, the lower sheet fractures for a small total thickness because of the relatively large length of the rivet leg. The joinability of three sheets can be evaluated as two sheets when the upper and middle sheets were made of the same material.