Finite Element Modelling and Laboratory Simulation of High Speed Wire Rod Rolling in 3-Roll Stands

Abstract

Modern wire rod rolling is characterized by high finish rolling speed and requirements on close tolerances and well defined mechanical properties of the rolled product. In some senses the technological development has run in advance of the scientific knowledge of the phenomena involved in the process. Thus at present no laboratory mill is in operation for rolling speeds above 40 m/s. The modern technologies on thermomechanical rolling and sizing give certain phenomena difficult to handle for the mills, and especially finish rolling at low reductions and temperatures performed in three‐roll units sometimes give surprises on grain size distribution and allied properties of the wire rod. Traditional plastic analysis has proven not to be sufficient to analyse the processes involved in high speed rolling of close tolerance wire rod with well‐defined properties. Simulations by means of the Finite Element Method on the other hand have proven to be a powerful tool for this kind of analysis, even if the initial difficulties in creating a suitable model require certain care. Also the calculation capacity must be sufficient for making relevant three‐dimensional thermomechanically coupled studies. The high speed rolling of wire rod can be simulated under full‐scale conditions, and with correct boundary condition in the high‐speed laboratory wire rod mill at Örebro University. By utilizing both conventional two‐high stands and three‐roll units it has been possible to design a laboratory rolling mill for any rolling condition that can occur in wire rod mills. Rolling speeds up to 80 m/s can be combined with thermomechanical rolling in any interesting temperature range, and with total flexibility of reductions. Further, fundamental studies of high‐speed deformations can be performed in full‐scale and with correct frictional conditions and geometries. Thanks to the flexibility in layout and combinations with other equipment in the laboratory also other processes can be simulated.