Metalurgické a techologické aspekty odlévání hmotných odlitků ze slitin železa

Abstract

This PhD thesis focuses on the research of material and cast properties of high weight castings made from steel and iron. Typical features of heavy castings are large module and long setting time. The main part of the dissertation deals not only with the study of crystallization depending on the metallurgical processing of molten steel, but also with the issue of producing castings from nodular cast iron (GJS) with increased silicon content. Technologies that enhance metallurgical quality of heavy castings are validated experimentally. Using the castings of alloy steels, it was proven that calcium influences the liquidus and solidus temperature, surface quality and distribution of mechanical properties over the cross section of the casting. Conditions of chunky graphite formation depending on the conditions of test castings solidification made from ductile iron were defined analytically.