For the optimization of the processing conditions and for the description of the metallurgical phenomena involved during rod rolling and cooling at the Stelmor conveyor, a microstructural based process model called CAROD has been developed. Triggered by the temperature history from the reheating furnace to the coiling, deformation processes like recrystallization, austenite grain size development and transformation kinetics are described. Depending on steel grade, rolling schedule and other processing parameters, the final microstructure and mechanical properties are predicted. The model components were tested separately using a Gleeble machine. The effects of the most significant influencing parameters, such as finishing rolling temperature, cooling strategy, rolling speed and others have been determined. The model has been validated for a wide range of steel grades with a tensile strength between 370 and 1400 N/mm(2). Special emphasis has been laid on the thermo-mechanical treatment of cold heading qualities, which leads to a soft microstructure, whereby in many cases the subsequent soft annealing can be saved. The accuracy of the model is also sufficient to reduce the effort for final destructive materials testing. Experimental verifications by thermo vision, measurements at the plant and by Gleeble simulation as well as fundamental studies of the property-determining processes have been performed.