Abstract
This paper presents the research results of application of Lost foam process for aluminum alloys castings of a simple geometry. The process characteristic is that patterns and gating of moulds, made of polymers, stay in the mould till the liquid metal inflow. In contact with the liquid metal, pattern intensely and in relatively short time decomposes and evaporates, which is accompanied by casting crystallization. As a consequence of polymer pattern decomposition and evaporation a great quantity of liquid and gaseous products are produced, which is often the cause of different types of casting errors. This paper presents the results of a research with a special consideration given to detecting and analyzing the errors of castings. In most cases the cause of these errors are defects of polymer materials used for evaporable patterns production, as well as defects of materials for refractory coatings production for polymer patterns. The researches have shown that different types of coatings determine properties of the obtained castings. Also, the critical processing parameters (polymer pattern density, casting temperature, permeability of refractory coating and sand, construction of patterns and gating of moulds) significantly affect on castings quality. During the research a special consideration was given to control and optimization of these parameters with the goal of achieving applicable castings properties. The study of surface and internal error of castings was performed systematically in order to carry out preventive measures to avoid errors and minimize production costs. In order to achieve qualitative and profitable castings production by the method of Lost foam it is necessary to reach the balance in the system: evaporable polymer pattern - liquid metal - refractory coating - sandy cast in the phase of metal inflow, decomposition and evaporation of polymer pattern, formation and solidification of castings. By optimizing the processing parameters castings of required structural and mechanical characteristics could be achieved, casting defects characteristic for this process could be avoided with the result of the production costs saving. The presented results can be useful to define parameters of Lost foam process and its application in practice with objective to obtain castings with in advance specified quality.
Highlights
This paper presents the research results of application of Lost foam process for aluminum alloys castings of a simple geometry
This paper presents the results of a research with a special consideration given to detecting and analyzing the errors of castings
The presented results can be useful to define parameters of the Lost foam process and its application in practice with objective to obtain castings within advance specified quality
Summary
U radu su prezentirani rezultati istraživanja primene “Lost foam” procesa (tj. livenje primenom isparljivih modela) za livenje odlivaka legura aluminijuma. Na strukturu i svojstva odlivaka utiču i drugi procesni parametri koji su istraživani u korelaciji sa gustinom modela, vrstom i debljinom sloja vatrostalnog premaza, a pre svega istraživan je uticaj temperature livenja, vrsta i veličina zrna peska za kalupovanje, odnosno propustljivost peska za kalupovanje, konstrukcija modela i ulivnih sistema. Ove vrste polimera korišćene su za izradu modela kod livenja legura gvožđe–ugljenik s ciljem da se eliminiše pojava svetlog ugljenika na odlivcima, a takođe, da bi se izbeglo stvaranje velike količine gasovitih produkata razlaganja i isparavanja modela pri ulivanju metala [6]. U radu je posebna pažnja posvećena analizi pojava i procesa razlaganja i isparavanja polistirenskog modela pri različitim procesnim parametrima i njihov uticaj na strukturu i svojstva dobijenih odlivaka. Formiranja i kristalizacije odlivaka zahtevali su sistematična istraživanja sinteze i karakterizacije vatrostalnih premaza različitih sastava za primenu u Lost foam procesu
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.