Self-pierce riveting of three high strength steel and aluminium alloy sheets

The joinability of the self-pierce riveting process of three high strength steel and aluminium alloy sheets was investigated. The effects of the sheet strength and sheet combination on the deforming behaviour were examined under the fixture of the lower aluminium alloy sheet. Although the joining of three aluminium alloy and mild steel sheets is comparatively easy due to small difference of strength, the joining becomes difficult with the increase in strength of the high strength steel sheet. To improve the joinability with the high strength steel sheets, a shape of the die was optimised by controlling the deforming behaviours of the sheets and rivet by means of the finite element simulation. The joining range of three high strength steel and aluminium alloy sheets was extended by means of the optimised die.