The forging and heat treatment process developments at Raufoss have during the last years given advantages in the manufacturing of safety parts for automobiles. There is a market growth of lightweight wheel chassis parts, aluminium through the last years. The opportunity for using forging seems promising if the costs are kept on a low level, the input material is a critical issue.
A process route that has been suggested newly is casting of forging stocks by a horizontal direct chill (HDC) casting technique to make small diameter billets without extrusion. A modified value chain in manufacturing of forgings at significant lower costs opens.
When discussion parts with high level of structural integrity aluminium based it is obvious that improvements are necessary for future position of light weight parts in the automotive industry due to the high cost. Castings mostly have too low mechanical properties to reach a level of high structural integrity, hot deformation seem necessary.
The understanding of the transformation of the cast microstructure into a wrought sate is a key point, especially the focus on ductility. The breakdown of cast is mostly understood as a refinement of primary phases and break up of oxides and inclusions. A detailed study of increased ductility with deformation at elevated temperature demonstrate the importance of the grain structure and sub-structure on the properties. The EBSD technique has given a breakthrough in the knowledge of what gives improved ductility and at what level do a cast base material can be stated as a forging. The new knowledge is a basic fundament for introduction of cast rod into forging of safety critical automotive parts.