Undersökning av bindningsmekanismer vid pressning av metallaminat : Investigation of bondning mechanisms at the pressing of metal laminates

Sammanfattning: Increased understanding of the mechanisms that operate in conjunction with the welding of metal surfaces may help to improve existing manufacturing processes, and to enable new products and combinations of materials. The purpose of the project has therefore been to acquire a deeper understanding of what is happening in the bond for steel and for the factors that form the basis for a bond to develop between metals in the production of laminates by pressing. The merge has been done by pressing and the surfaces after the experiments have been studied in detail in the scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX) and with interferenceprofilometry in Wyko, to provide a greater understanding of the mechanisms that influence the bonding in the interface between metals.   The project was limited to contain the materials Docol 1000, HyTens 1200, Aluminum AA3003 and a commercial steel. The parameters varied in the experiments to study their influence closer are temperature, pressure, heat treatment and pretreatment. This has been implemented by pressing with varying temperature and pressure. The materials have been pressed at room temperature or heated in an oven at 300 or 600 degrees and pressed immediately after the levying. Pretreatment was done by cleaning in acetone followed by either brushing or sandblasting alternatively no pretreatment have been done at all. The result was that the increased pressure and increased temperature increases the chance of joining by pressing. Pressing at slightly elevated temperature (about 100-250 degrees, depending on the material) makes bonding possible for metals which are not joined together at room temperature. Pretreatment by sandblasting gives a rougher and more riddled surface than brushing. At the cracking in the oxide layer at the pressing, wells new clean metal into between the oxides to the surface. When the new material reaches the surface, a joint can be made with the opposite clean material. The clean metal that wells up, then flows in a pattern which presses down the oxide in the material, away from the surface. This is done so more clean material can come to the surface and a finer binding can be obtained.