Vliv chemického složení na tvrdost kolejnic

Abstract

The present baccalaureate thesis seeks to describe how the chemical composition os steel affects hardness of rails. The theoretical part deals with the manufacturing process that allows reducing the content of elements that may have adversary effects on hardness. Further, it gives a brief account of the principle underlying hardness measurements and the differences between the values measured at various depths of the rail head. The main portion of the theoretical and experimental part seeks to compare the effects of individual elements on hardness for selected types of rails. In the theoretical part, the said issues are addressed for pearlite and bainite structure rails, while the experimental part deals with selected R 260 and IH steel grade rails. The next part of the paper addresses the effects of the chemical composition on hardness at the welding of rails and it describes the other factors having an impact on hardness. The results of the paper were established by means of an analysis of data obtained for Třinecké železárny heats.