Comparison of evaluation methods of the chemical inhomogeneity of ductile irons alloyed with graded nickel contents

• Autorzy: Vojtkuláková Z. , Pacal B.
• Konferencja: Metody oceny struktury oraz własności materiałów i wyrobów / Międzynarodowe Sympozjum (XIX ; 30.11.-02.12.2004 ; Rožnov pod Radhoštěm, Czechy)
• Języki publikacji: EN

Abstrakty

EN

Graphite irons are multicomponental systems of Fe-C-Si-Mn-i, where i presents another possible additional element. Chemical inhomogeneity of their matrix strongly affects their mechanical and physical properties, and therefore their technical usage. Elemental redistribution during eutectic crystallization is determined, among others, by the distribution coefficients of an element M between the austenite and the melt saturated with carbon. To describe the elemental redistribution, effective distribution coefficient kef(M) is used. The kef(M) is defined as the ratio of concentration of the element M near the graphite to that measured at the periphery of the eutectic cell. Many distribution coefficient measurements in graphite irons show that elements increasing thermodynamic activity of carbon concentrate near graphite, hence their kef(M) after solidification is greater than 1. These are Si, Ni, Cu, Mg, P, S, Al and Co. On the contrary, elements like Mn, Cr, V and Mo, having kef(M) usually smaller than 1, concentrates at the eutectic cell boundary. The contribution deals with comparison of kef(M) for Si and Ni in the as cast state and after heat treatment. Two different methods were used for the effective distribution coefficient determination. Previous experiences show that reliably reproducible determination of kef(M) is possible only for the alloying element content in the order of units of weight percent. For the lower alloying elements content (in the order of 0.1 wt. %), the standard deviation grows due to the cast iron matrix inhomogeneity.

Słowa kluczowe

EN

graphite irons

• Wydawca: Oficyna Wydawnicza Politechniki Opolskiej
• Czasopismo: Zeszyty Naukowe. Mechanika / Politechnika Opolska
• Rocznik: 2004
• Tom: z. 78
• Strony: 195--200
• Opis fizyczny: Bibliogr. 7 poz., tab., wykr.

Twórcy

autor

Vojtkuláková Z.

• Brno University of Technology

autor

Pacal B.

Bibliografia

• [1] PACAL B., STRANSKf K., VOJTKULÄKOVÄ Z., ZEMĆÓC L., KLAKURKOVÄ L., MUXON B.: Pnspevek k heterogenite matrice LKG legovanych niklem, In: 8. konference „Pfinos metalografie pro feseni vyrobnfch problemu", Mariänske Läzne, cerven 1999, pp 93-96
• [2] ZEMCÖC L. a kol.: Modely rüstu grafitu v sede tuhnoucfch litinäch a jejich aplikace, grant GA ĆR c. 106/96/1293, oponovanä zäverecnä zpräva: 1997
• [3] MÜNSTEROVÄ E. a kol.: Expertni databäzovy system metalurgickych, strukturnich a mechanickych Charakteristik tvärnych litin pro konvencni a nekonvencni pouźitf, grant GA ĆR ć. 106/96/0962, oponovanä zäverecnä zpräva, 1998
• [4] PACAL B., VOJTKULÄKOVÄ Z., STRANSKY K.: Hodnoceni heterogenity matrice LKG legovanych niklem, In: konference „Slevärny do 3. tisicileti", Plzeń 1999, sbornik ZĆ VTS, pp 65-74
• [5] PACAL B., STRANSKY K., VOJTKULAKOVA, Z.: Hodnoceni heterogenity matrice niklovych LKG. In: Mezinarodrn konference Materialove vedy na prahu 3. milenia, Brno, srpen-zafi 1999, pp 198-201
• [6] PACAL B., VOJTKULAKOVA Z.: Hodnoceni chemicke nehomogenity u niklovych LKG, In: 9. konference ,,Pffnos metalografie pro fesem vyrobmch problemu", lazne Libverda, cerven 2002, pp. 194-198
• [7] DOLEŹAL P., VOJTKULAKOVA Z., PACAL B: Hodnoceni strukturni a chemicke heterogenity na vzorcich z LKG, In: 9. konference „Pffnos metalografie pro feseni vyrobnich problemu", lazne Libverda, cerven 2002, pp. 343-346