FORMABILITY OF STEELS FOR ROLLING OF WIRE ROD

The paper presents results of steel 23MnB4 and C70 plasticity tests meant for rolling wire rods on modern continuous rolling mill. Plasticity assessment was conducted in hot torsion test performed on swing plastometer in temperature range of rolling wire rode from 850 to 1150 degrees C and deformation speed of 0.1; 1 and 10 s(-1). The basis for plastic ity assessment was the dependency between flow stress and deformation achieved on the basis of registered torsion moment in function of the number of sample torsions. On such basis the characteristic values were determined: peak flow stress, deformation value which corresponds with peak stress and deformation to failure. Those values are dependent on deformation parameters and certain dependencies between peak flow stress and corresponding deformation with activation energy of the deformation process and Zener-Hollomon parameter were elaborated.