Uticaj karakteristika procesa livenja na mikrostrukturu i mehaničke osobine višekomponentne legure mesinga

Abstract

The castings must have certain characteristics in order to be used in defined exploitation conditions. In this paper, the influence of centrifugal force, fluid dynamics and solidification conditions on the microstructure and mechanical properties of the multicomponent brass alloy CuZn26Al4Fe3Mn3 was studied. The castings of the same dimension, are cast by the process of gravity and centrifugal casting. The experiment was performed under conditions which are insured that parameters such as melting temperature at the start of casting, pouring rate, metallostatic pressure, have no effect on the investigated properties. The metallographic analysis of the samples was performed with the optical microscope Carl Zeiss Jena Epitip 2. The hardness and tensile strength of the samples were measured with Rocka TH-160 device. The obtained results indicate that values of mechanical characteristics, hardness and tensile strength are higher in the samples obtained by the centrifugal casting process. It is noticed, that the microstructure of the centrifugal casting is fine-grained and compact with rounded grains, while the microstructure of the gravity casting is dendritic with an orientation that coincides with the direction of heat removal. The experiment showed, that with the proper choice of applied casting techniques the desired structure and characteristics of the castings can be obtained.