Vliv deformační rychlosti na ARA diagram nízkolegované Cr-Ni oceli

Abstract

The diploma thesis is divided into theoretical and experimental part. The theoretical part deals with the disintegration of austenite in steels and methods for determining the phase transformations temperatures. It also describes the transformation diagrams of steels and the parameters affecting these diagrams. In the last point of the theoretical part are listed and described the possibilities of using transformation diagrams. The experimental part describes the investigated steel 41Cr4 low-alloyed with Cr and Ni, used experimental equipment, dilatometric tests, structural analyses and measurement of hardness. Based on the performed experiments, CCT transformation diagrams were constructed with the influence of previous deformation at two different levels of strain rate. By comparing these diagrams, the influence of the strain rate on the individual phase transformations during cooling was assessed. The differences between the two diagrams can be explained by the various course of dynamic recrystallization, which affected the austenitic grain size.