Szczegóły publikacji

Opis bibliograficzny

Autorzy (2)

• AGHKawalec Magdalena
• AGHMaj Maria

Słowa kluczowe

Dane bibliometryczne

ID BaDAP	82787
Data dodania do BaDAP	2014-08-22
Rok publikacji	2014
Typ publikacji	materiały konferencyjne (aut.)
Otwarty dostęp
Konferencja	71st World Foundry Congress: Advanced Sustainable Foundry

Abstract

Owing to its favorable mechanical and technological properties cast iron remains not only the most commonly used casting alloy but is still under development. This is a material whose properties can be influenced in a wide range of values through changes in the microstructure. The microstructure can be changed through inoculation, spheroidisation, vermicularisation and heat treatment. Another possibility is introducing to the cast iron certain quantities of alloying elements that change the type of matrix or the morphological features of graphite or induce crystallization of various carbides. One of the alloying elements with very interesting properties is vanadium. Literature gives only very scarce data on phase equilibrium diagrams, nucleation of vanadium carbides microstructure of Fe-C-V alloy systems and vanadium effect on the cast iron properties. Hence follows the purpose of this study including a series of high-vanadium cast iron melts of different chemical composition analysis of its microstructure and examination of mechanical and tribological properties. The study presents the results of metallographic examinations of the ready alloys, including quantitative and qualitative analysis of crystallized phases using optical microscopy and SEM. The research shows that in the high-vanadium cast iron eutectics of different types can crystallize: fibrous, complex regular and globular-like. Primary carbides can also crystallize in the form of non-faceted or faceted dendrites. The examined alloys were observed to have a matrix composed of alloyed ferrite, granular pearlite, lamellar pearlite or a mixture of these components. In terms of the type of microstructure the conducted mechanical tests showed that high-vanadium cast iron can be divided into five groups. With the cast iron matrix changing from a ferritic one through granular pearlite to lamellar pearlite the hardness (HBW), the tensile strength (Rm) and the yield strength (Rp0.2) are increasing, while plastic properties of the alloy decrease as expressed by the elongation (A5). Additionally the presence of cementite eutectic in the alloy structure favours the increase of hardness and the drop of plastic properties. It should also be noted that compared to plain white cast iron characterized by high brittleness and unmachinable with conventional cutting tools, the F-C-V alloys (vanadium white cast iron) are machinable and offer a range of plastic properties (e.g. in the case of ferritic matrix) which depend on the morphology and content of vanadium carbides (both eutectic and primary) and on the type of matrix. Moreover alloys with the eutectic mixture which crystallizes in the form close to a globular one show quite satisfactory plastic properties while maintaining high mechanical characteristics. Tribological tests showed large differences in the resulting abrasion resistance. As in the case of mechanical properties also the abrasion wear resistance is dependent on the type of the crystallized microstructure. The examined vanadium cast iron has a very high resistance to abrasion. It is possible to obtain Fe-C-V alloys with the abrasion wear resistance superior to the abrasion wear resistant cast steel.

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