Fázové transformace probíhající během ochlazování laboratorně válcovaných ocelových tyčí

Abstract

With using of laboratory semi-continuous rolling mill of round bars and by using dilatometric tests was examined the influence of parameters of forming on the temperatures of phase transformations Ar3 and Ar1 during free cooling of rolled products of unalloyed low carbon structural steel S235JR. With decreasing of average rolling temperature the temperature Ar3 was increased, while the size of the total strain, respectively varying degrees of forming rolled products did not have a significant effect on the size of the temperature Ar3.In the case of the temperature Ar1 showed no effect of average temperature rolling on their size. Greater degree of forming rolled products had the effect of reducing the temperature Ar1. Based on the evaluation dilatometric test was for the given conditions of heating and cooling rate constructed CCT diagram without and with the influence of the previous deformation. Applications of deformation resulted in the extension of the ferritic area, i.e. the shift of points Ar3 to higher temperatures and Ar1 to lower temperatures.