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1

The carburizer influence on the crystallization process and the microstructure of synthetic cast iron

Janerka K., Bartocha D., Szajnar J., Jezierski J.

Archives of Metallurgy and Materials

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2010

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Vol. 55, iss. 3

851-859

EN

The problems of synthetic cast iron production on the steel scrap and various carburizers (natural and synthetic graphite, petroleum coke, anthracite, cupola coke and charcoal) basis were presented in the paper. Until now the authors in their papers had analyzed mainly carbon assimilation by the liquid metal rate (recarburization efficiency) when these carburizers and various methods of recarburization were used [1,2,3,4]. The analysis covered the chemical composition and the properties of carburizers commonly used in foundries [5,6] and mechanical properties of the cast iron obtained on the steel scrap basis, too [2,7,8,9]. The computer modeling of heating and dissolution of carburizers’ particles inside liquid metal were carried out, too [10,11]. The crystallization process of the synthetic cast iron analysis and that produced on pig iron basis for comparison were presented. There was observed that the carburizers change the DTA (Derivative Thermal Analysis) curves in specific temperature ranges. The authors presented some experimental results in form of recorded DTA curves. The presented results show also carburizers microstructures and synthetic cast iron and made on pig iron basis structures, too. The problems given under consideration in the paper has a purpose of set up a discussion on "heredity of cast iron" – some charging materials properties transferred to cast iron. Does such an issue exist and if yes, in what extent it decides of melted alloys properties (synthetic cast iron in described example)?

PL

W artykule przedstawiono zagadnienia związane z wytwarzaniem żeliwa syntetycznego na bazie złomu stalowego i różnych rodzajów materiałów nawęglających (grafitu naturalnego i syntetycznego, koksu naftowego, antracytu, koksu odlewniczego i wegla drzewnego). Dotychczas autorzy w swoich publikacjach analizowali przede wszystkim stopień przyswojenia węgla przez ciekły metal (efektywnosc nawęglania) przy stosowaniu tych nawęglaczy i różnych metod nawęglania [1,2,3,4]. Analiza obejmowała również skład chemiczny i właśnosci najczęściej stosowanych w odlewnictwie nawęglaczy [5,6] oraz własności mechaniczne żeliwa wytopionego na bazie złomu stalowego [2,7,8,9]. Prowadzone są równiez symulacje komputerowe procesu nagrzewania i rozpuszczania cząstek nawęglaczy znajdujących się w ciekłym metalu [10,11]. W artykule przedstawiono analizę procesu krzepnięcia żeliwa syntetycznego i dla porównania żeliwa uzyskanego na bazie surówki. Zauważono, że materiały nawęglajace zmieniają przebieg krzywych Analizy Termiczno Derywacyjnej w pewnych zakresach temperatury. Autorzy przedstawili część uzyskanych wyników pomiarów w postaci zarejestrowanych krzywych ATD. Zaprezentowany materiał obejmuje również struktury materiałów nawęglających i struktury żeliwa syntetycznego oraz wytopionego na bazie surówki. Podjęta w artykule tematyka ma na celu wywołanie dyskusji o "dziedzicznosci" cech materiałów wsadowych przenoszonych do żeliwa. Czy takie zagadnienie istnieje i w jakim stopniu decyduje o własnościach wytopionych materiałów (w analizowanym przypadku żeliwa syntetycznego)?

2

The properties and structure of the carburizers

Janerka K., Jezierski J., Pawlyta M.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 1

67-74

EN

The results of examinations of the carburizers for foundry industry were presented in the article. The commonly used carburizers were selected for the experiments (anthracite, natural and synthetic graphite, petroleum coke of various grades), cupola coke and charcoal as well. The experiments consist of bulk and standard density, screen analysis (on the basis of it the equivalent diameter was calculated) and the microstructure of the carburizers measurements. The chemical composition and basic properties of carburizers were described too.

3

Carburizer particle dissolution in liquid cast iron - computer simulation

Bartocha D., Janerka K.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 1

7-14

EN

In the paper issue of dissolution of carburizing materials (anthracite, petroleum coke and graphite) particle in liquid metal and its computer simulation are presented. Relative movement rate of particle and liquid metal and thermophsical properties of carburizing materials (thermal conductivity coefficient, specific heat, thermal diffusivity, density) are taken into consideration in calculations. Calculations have been carried out in aspect of metal bath carburization in metallurgical furnaces.

4

The sort of carburization and the quality of obtained cast iron

Janerka K., Bartocha D.

Archives of Foundry Engineering

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2008

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Vol. 8, iss. 4

55-60

EN

In the production of cast iron, the pig iron's amount in charge material is more and more often limited, and replaced by steel scrap. That extorts the necessity of know-how the carburization and one is looking for carburizers, which ensure obtaining big carbon increment as quickly as possible with the high repeatability and the ones which ensure getting the adequate quality of cast iron. The object of presented research was definition of the influence of charge materials' sort on the structure, course of solidification, and the effectiveness of process. The cast iron melts, which are presented below, are made only on the basis of steel scrap with portion of graphitoidal, coke and anthracite carburizers, which were added to the charge in solid. In the article one compared the carburizers in respect of their structure, chemical constitution and the effectiveness obtained during the carburization of liquid metal. The melting of cast iron, based on the special pig iron, was carried out as well. The course of melts, chemical constitution of obtained cast iron and its structure were presented. The comparison between quality distribution and the volume fraction of graphite in classes of size for the individual melts were achieved and the TDA curves were inserted.

5

The rate and effectiveness of carburization to the sort of carburizer

Janerka K.

Archives of Foundry Engineering

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2007

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Vol. 7, iss. 4

95-100

EN

The obtaining of demanded carbon contents during melting the cast iron with bounded pig iron's portion is important problem for many foundries. There are searched the effective methods and carburizers, which would ensure obtaining of big carbon increases with great repeatability as quick as possible. The aim of presented researches was definition of influence of essential factors characterized the carburization and the sort of carburizer on the rate and effectiveness of process. The cast iron melts are presented only on the basis of steel scrap with the portion of graphitoidal, coke and anthracite carburizers. Two methods of carburization are taken into consideration during the experiments were carried out: the addition of carburizer to charge in solid in the initial period of melting and addition of carburizer on surface of liquid metal. The obtained researches results and their analyze allow to choose the corresponding method and the sort of carburizer. One can state, that the best carburizer is synthetic graphite, if the rate and effectiveness of process is considerate and the best method of carburization in the electric inductive furnace is addition of carburizer to charge in solid. In the subsequent part of researches the analyze of influence of carburizer on the structure of grey cast iron and ductile cast iron. The initial researches has showed the differences in obtained structures of synthetic cast iron melted only on the basis of steel scrap and defined kind of carburizer.