TESTS TO SIMULATE THE TEMPERATURE-CONTROL LED ROLLING OF BAR STEEL

Objective. During rolling of bar steel it is possible to observe that disturbances in the production process negatively affect the quality o f the rolled stock. The causes of this may be unfavourable residual st resses and unfavourable microstructural conditions. The present articl e reports on the simulation of thermal and deformation processes under gone by bar steel and draws attention to the possibility of model test s helping to decisively optimize the rolling process. Summary. It was possible to demonstrate that model tests performed in a high-temperatu re tensile testing facility, complemented by a determination of the de formation-time-temperature-transformation (DTTT) curve in a dilatomete r compression test, are able to simulate the deformation processes tak ing place during the thermomechanical controlled rolling of bar steel. Certain correspondences can be established by comparing the microstru ctural conditions achieved in the temperature-controlled tensile testi ng with the structures formed during the thermomechanical controlled t est rolling. The same applies to the resulting residual stresses also determined in the test pieces deformed by means of the two methods. Bo th the quantitatively defined state of stress, characterized by the st ress distribution at the surface and in the throug-thickness direction , and the strain-hardening demonstrated by hardness measurement are su itable starting points for the prediction of the deformation behaviour .