Vliv cementových forem na povrchovou strukturu odlitků

Influence of Cement Moulding Sands on the Structure of Castings

conference proceedings

en

Technologies and materials used in industry are still more influenced by ecological aspects and demands. In foundries, the use of resins as a binder in moulds worsens the working conditions due to toxic combustions products emitted during pouring. The second serious problem is the needed recyclability of the used moulds, because until now, 50% of this material is disposed. This paper presents the results of the investigation of new hydraulically setting binders in foundry moulds with contact of liquid grey and nodular iron. These binders based on Alumina and Portland cements are environmentally friendly and exhibiting admirable performance. Methodology of trials was designed and its attestation was implemented in experimental and working conditions. In the interface between cement sands and liquid metal were certified generation of complex allied substances – on the base of Si, Fe, Al and Ca. In many cases compounds of sulphur, which are dangerous and could change the shape of graphite nodules in the surface layers of castings have been found. All these particles are illustrated by SEM microscopy. The mathematical model of mechanical penetration has been created and proved influence of the temperature and chemical composition of grey iron on the range of penetration in the experimental moulds. The research and development of these inorganic binders for the foundry use will be the solution for future of no waste technologies.

Článek prezentuje výsledky výzkumu a vývoje ekologicky přátelských formovacích směsí na bázi portlandského cementu a popisuje reakce na rozhraní při odlévání litin s lupínkovým a kuličkovým grafitem.

Technologies and materials used in industry are still more influenced by ecological aspects and demands. In foundries, the use of resins as a binder in moulds worsens the working conditions due to toxic combustions products emitted during pouring. The second serious problem is the needed recyclability of the used moulds, because until now, 50% of this material is disposed. This paper presents the results of the investigation of new hydraulically setting binders in foundry moulds with contact of liquid grey and nodular iron. These binders based on Alumina and Portland cements are environmentally friendly and exhibiting admirable performance. Methodology of trials was designed and its attestation was implemented in experimental and working conditions. In the interface between cement sands and liquid metal were certified generation of complex allied substances – on the base of Si, Fe, Al and Ca. In many cases compounds of sulphur, which are dangerous and could change the shape of graphite nodules in the surface layers of castings have been found. All these particles are illustrated by SEM microscopy. The mathematical model of mechanical penetration has been created and proved influence of the temperature and chemical composition of grey iron on the range of penetration in the experimental moulds. The research and development of these inorganic binders for the foundry use will be the solution for future of no waste technologies.

Iron, Casting, Mould, Cement, Sand, Interaction

16.10.2010

Hangzhou

Proceedings of 69 th World Foundry Congress

1

641–647

7