Improvement of Joinability in Mechanical Clinching of Ultra-high Strength Steel Sheets Using Counter Pressure with Ring Rubber

Abstract

A mechanical clinching using counter pressure of a rubber ring was developed to join the galvanised ultra-high strength steel sheets having low ductility. In the proposed process, the interlock was increased by the increment of metal flow with the counter pressure of rubber ring in the die cavity. The ultra-high strength steel sheets having 45% of reduction area was used in the mechanical clinching. The effect of the shape of rubber ring on the deforming behaviour of the sheets was investigated. The joinability was improved under the appropriate shape of rubber ring, and then the sheets were successfully joined with the counter pressure. The maximum static load and the fatigue limit of the joined sheets were measured in the tension-shearing and cross-tension tests. It was effective for the improvement of joinability in the mechanical clinching of ultra-high strength steel sheets to use the counter pressure of the rubber ring.