Racionalizace výroby odlitků z grafitizujících slitin železa

Abstract

The subject of this thesis is optimization of the process of core making for production of castings of graphitizing iron alloys. Rationalization of production included optimization of composition of core sands for the purpose of achievement of high surface quality of pre-cast holes in selected iron castings. The theoretical part of the thesis contains description of properties of quartz and non-quartz sand grains, their advantages and disadvantages. The most frequently used sand grains are quartz sand grains, mainly for economic and a lot of technological reasons. Unfortunately, they have also many drawbacks, such as discontinuous thermal expansion, increased reactivity in the heat, and silicosis. Those disadvantages are compensated by application of non-quartz sand grains. The objective of this thesis is finding suitable non-quartz sand grains for achievement of better surface quality of castings, evaluation of their physical and chemical properties, influence on technological properties of core sands, surface quality of pre-cast cavities and holes, complexity of finishing of castings, and economical evaluation of their application.