Geometrical modulus of a casting and its influence on solidification process

• Autorzy: Havlicek F. , Elbel T.
• Języki publikacji: EN

Abstrakty

EN

Object: The work analyses the importance of the known criterion for evaluating the controlled solidification of castings, so called geometrical modulus defined by N. Chvorinov as the first one. Geometrical modulus influences the solidification process. The modulus has such specificity that during the process of casting formation it is not a constant but its initial value decreases with the solidification progress because the remaining melt volume can decrease faster than its cooling surface. Methodology: The modulus is determined by a simple calculation from the ratio of the casting volume after pouring the metal in the mould to the cooled mould surface. The solidified metal volume and the cooled surface too are changed during solidification. That calculation is much more complicated. Results were checked up experimentally by measuring the temperatures in the cross-section of heavy steel castings during cooling them. Results: The given experimental results have completed the original theoretical calculations by Chvorinov and recent researches done with use of numerical calculations. The contribution explains how the geometrical modulus together with the thermal process in the casting causes the higher solidification rate in the axial part of the casting cross-section and shortening of solidification time. Practical implications: Change of the geometrical modulus negatively affects the casting internal quality. Melt feeding by capillary filtration in the dendritic network in the casting central part decreases and in such a way the shrinkage porosity volume increases. State of stress character in the casting is changed too and it increases.

Słowa kluczowe

EN

modulus of casting; solidification rate; casting quality

PL

moduł odlewniczy; krzepnięcie; jakość odlewu

• Wydawca: Komisja Odlewnictwa Polskiej Akademii Nauk Oddział w Katowicach
• Czasopismo: Archives of Foundry Engineering
• Rocznik: 2011
• Tom: Vol. 11, iss. 4
• Strony: 170--176
• Opis fizyczny: Bibliogr. 19 poz., tab., wykr.

Twórcy

autor

Havlicek F.

autor

Elbel T.

• VSB - Technical University of Ostrava, 17. listopadu 15, CZ 708 33 Ostrava-Poruba, Department of Foundry Engineering, FMMI,

Bibliografia

• [1] N.Chvorinov : Control of the Solidification of Castings by Calculation. Proc. Institut of British Foundryman,32, (1938-39), p. 229-236.
• [2] P-R. Sahm . et al. : Schmelze, Erstarrung ,Grenzflächen. Vieweg Runschweig, Wiesbaden, (1999).
• [3] D. M. Stefanescu : Science and Engineering of Casting Solidification. Cluver Academic/Plenum Publishers, New York, (2002).
• [4] J. Campbell : Castings . Elsevier Butterwiörth Heinemann, Oxford (2003).
• [5] P. R. Schlegg et al. Technology of Metalcasting , AFS Publication, (2003).
• [6] J.Dantzig, M. Rappaz: Solidification, EPEL Press, Lausanne. (2009).
• [7] F. Havlíček : Physical laws of directional solidifivation of castings.. Sborník vědecjých prací VŠB, řada hutnická, XXXVII, 2/1991, s.49-68. (In Czech).
• [8] F. Havlíček, Z. Košňovský: Evaluation of solidification velocity in castings. .Slévárenství, XXVI, (1978), č.1,p.12-20.(In Czech).
• [9] N. Chvorinov: Theorie der Erstarrung von Gußstücken. Gießerei,27, 1940, heft 10, s.177-188, heft 11, 201-208. Heft 12. p.222-225.
• [10] G. Halbart: Elements d´une theorie mathematique de la fonderie. Editions R. Vaillant-Carmanne , Liege, (1945).
• [11] T. Elbel: From Chvorinov´s rule to numerical modelling of casting sdolidification. Proceedings of CHVORINOV´S COLLOQUIUM, VŠB-TU Ostrava,(2009) , p.34-35. (In Czech).
• [12] W. Longa: Solidification of castings. Wydawnictwo Śląsk, Katowice,(1985), (In Polish).
• [13] N. Chvorinov: Study of steel solidification Theoretical solutions. Hutnické listy, roč.VI, (1951), č.,11, p.594-598.(In Czech).
• [14] W. Longa: Solidification of casting in sand moulds. Wydawnictwo Śląsk, Katowice, (1973). (In Polish).
• [15] F. Havlíček : relationship of geometrical modulus of casting with the solidification process and internal stress. Sborník vědeckých prací VŠB -TU Ostrava, číslo 2. (2009), vol. LII, řada hutnická, článek 1461, p.87-102. (In Czech).
• [16] R. W.Ruddle: Risering - Past, Present and Future, AFS Transactions,vol. 79 , (1971),p. 269-280.
• [17] F. Havlíček: Theory of metal mouvement in two-phase zone during solidification of casting. Sborník vědeckých prací VŠB v Ostravě, řada hutnická, XV, (1969), č.1,p.49-81.(In Czech).
• [18] J. Jamar: Considération sur la cintique de la solidification. La Fonderie belge, (1971), Nr. 7-8, p.139-150.
• [19] R. G. Santos, A. Garcia: Thermal behaviour during the inward solidification of cylinders and spheres and the correlation with structural effects, International Journal Cast Metals Research, vol. 11, (1998). p 187-195.