Properties of clinched stainless steel sheets as a result of thermal loading
Jalanesh M.1*, Gerstein G.2, Hübsch C.2, Hübner S.1, Yarcu S. 1, Sezek O.1, Behrens B.-A.1, Rodman D.2, Maier H. J.2
 Institut für Werkstoffkunde (Institute of Materials Science), Leibniz Universität Hannover, An der Universität 2, 30823 Garbsen, Germany
2 Institut für Umformtechnik und Umformmaschinen (Institute of Forming Technology and Machines), Leibniz Universität Hannover, An der Universität 2, 30823 Garbsen, Germany
Golovko A.N. Properties of clinched stainless steel sheets as a result of thermal loading / Golovko A.N., J Alanesh M., Gerstein G., Hübsch C., Hübner S., Yarcu S., SezekO., BehrensB.-A., RodmanD., MaierH. J. // Пластична деформація металів : матеріали наук.-практ. конф. : тез. допов., 22-26 травня 2017 р., м. Дніпро. – Дніпро : [б.в.], 2017. – С. 48.
Clinching is a quite modern method of sheet joining which is more and more applied in the automotive industry. Owing to joining without rivet and through holes this process allows reducing joining time, weight and costs. In the present study two types of clinching were investigated: round and rectangular non cutting clinching systems. The influence of thermal loading on the mechanical properties and structure of clinch joining of 1 mm thick sheets of ferritic and austenitic steel (1.4509, 1.4512 and 1.4301) were investigated. Clinched samples and standard tensile test specimens were loaded 10 times to temperatures of 400 °C, 750 °C or 900 °C for 10 minutes with a subsequent cooling to 50 °C for approximately 3 minutes each time. The clinching joining was tested in shear and peeling tension tests. It was observed that clinched samples after loading at 400 °C feature about twofold strength values compared to unloaded samples. It is remarkable that by the same thermal loading no significant changing of the properties in the sheet material was observed. Loading at 750 °C and 900 °C resulted in decreased strength values of the clinched samples compared to a thermal loading at 400 °C, though the values of these characteristics were significantly higher (after 750 °C) or close (after 900 °C) to that for unloaded samples. This effect was previously observed in some experimental investigations and can be explained by a combination of carbide coarsening and recrystallization at high temperatures. Thus, the behaviour of the considered clinching is suited for a usage at increased temperatures.