Application of cooling curve analysis in solidification pattern and structure control of grey cast irons

Riposan, Iulian; Chişamera, Mihai; Stan, Stelian

doi:10.1007/s10973-018-7023-3

Cited by 8 publications

(5 citation statements)

References 20 publications

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“…For cast irons, some important parameters are found in this way, such as liquidus temperature (austenite or primary graphite formation start), the start temperature of eutectic freezing (nucleation), the lowest and the highest eutectic temperatures and temperature of the end of solidification. By comparing these events with equilibrium temperature in stable (graphitic) and metastable (carbidic) solidification systems, some important information can be obtained, such as carbide to graphite transition, eutectic recalescence level (important as shrinkage formation sensitivity), primary (solidification) structure qualitative parameters, efficiency of inoculation (graphitizing treatment), graphitizing potential, graphite morphology, sensitivity to inter-eutectic cells carbide or microshrinkage formation etc [1][2][3][4][5][6][7][8][9][10][11][12] .…”

Section: Special Reviewmentioning

confidence: 99%

“…Increasing the acceleration rate of the graphitic expansion up to the maximum level (K gr1 ) leads to the decreasing of real density due to the presence of contraction defects. (6) Increasing the time of the expansion at the maximum level Δt[(ε di ) max ] favours the shrinkage formation, as a result of increasing the graphitic force on the mould walls, and consequently, decreasing the measured density of castings.…”

Section: Summariesmentioning

confidence: 99%

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Simultaneous thermal and contraction / expansion curves analysis for solidification control of cast irons

et al. 2020

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T he final control of the iron castings' quality involves different techniques, including chemical analysis, microstructure evaluation, physical and mechanical properties measurements, castings' surface parameters and casting soundness control, etc. It is important to forecast the final castings' characteristics before mould filling, by iron melt solidification control, applying techniques able to illustrate the eutectic undercooling values referring to the stable and metastable equilibrium temperatures, carbide or graphite formation tendency, a specific graphite morphology occurrence, metal matrix make-up, shrinkage and microshrinkage sensitivity, etc.Thermal (cooling curve) analysis has a wide application in the worldwide foundry industry to quickly control the solidification behaviour of foundry metallic alloys, especially for cast irons and non-ferrous alloys. At first, cooling curve analysis (CCA) *Iulian RiposanBorn in 1948, Ph.D, Professor. His research interests mainly focus on processing and complex characterization of lamellar, nodular, compacted/vermicular and coral graphite irons, austempered cast irons with lamellar, nodular, compacted or coral graphite, cast iron matrix composites, cupola and electric furnaces operations. To date, he has published more than 300 technical papers and 3 technical books, and holds 35 patents. He is the honorary member of Technical Sciences Academy of Romania, the Past President of Romanian Foundry Technical Association (ATTR) (1996 -2014), and an international member of American Foundry Society.

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Section: Special Reviewmentioning

confidence: 99%

Section: Summariesmentioning

confidence: 99%

Simultaneous thermal and contraction / expansion curves analysis for solidification control of cast irons

et al. 2020

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“…Inoculants are alloys added in small amounts to increase the number of active nuclei for the graphite nucleation and high effective grain refinement is achieved [4,5]. Inoculants are ferrosilicon alloys that may contain Al, Ca, Ba, Sr, Zr, and Rare Earths, which are known as inoculant elements that promote and participate in the creation of micron-sized active compounds in the melt, to act as effective graphite nucleation sites [6]. So, inoculants are added to produce heterogeneous nucleation of these graphite flakes and obtain the desired distribution.…”

Section: Introductionmentioning

confidence: 99%

Experimental assessment of the gray cast iron production by inoculant injection

Reyes-Castellanos

Cruz-Ramírez

Gutiérrez-Pérez

et al. 2021

J min metall B Metall

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An initial assessment of the gray cast irons production by injecting an inoculant with a conveying gas into a molten iron bath was evaluated at a laboratory scale. A numerical simulation was carried out to determine the hydrodynamic behavior between the inoculant particles injected into the molten iron. It was determined that an optimal interaction between the particles with the molten iron occurs at a lance depth of 7 cm and for the particle sizes fine (211 to 297 ?m) and medium (421 to 590 ?m), the residence time was of 0.38 and 0.4 s, respectively. The melting time was calculated at 0.0008 and 0.003 s for the particle sizes fine and medium, respectively. So, after injection, the FeSi of the inoculant melts quickly, releasing the elements of the inoculant which interact with the molten iron and forms oxides and sulfides creating nucleating sites during solidification. The injection technique allows obtaining a type-A graphite distribution for the fine and medium particle sizes. The number of eutectic cells was increased when the inoculant particle size was decreased despite of the low graphitisers elements, and manganese contents used in the gray cast iron manufacturing.

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“…Thermal analysis, based on the recorded cooling curves and their derivatives is one of the most effective technique, with a large industrial application, in control of solidification process in production of all of metallic castings, such as for aluminium alloys [3][4][5][6][7][8][9][10][11][12][13][14][15][16], copper alloys [3,17], zinc alloys [18], steel [19][20][21][22] and cast irons [1,8,[23][24][25][26][27][28][29][30][31][32][33]. Thermal analysis is also applied on solid state evaluation of the structure characteristics of other special metallic materials, as effects of different influencing factors, such as heat treatment and quenching media on the CuAlFeMn quaternary shape memory alloy [34].…”

Section: Introductionmentioning

confidence: 99%

Carbide to Graphite Transition Control by Thermal Analysis in Grey Cast Irons

Neacsu

Riposan

Cojocaru

et al. 2020

Metals

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The present work compared the solidification pattern of un-inoculated and inoculated hypoeutectic grey cast irons (3.7–3.8% CE), focused on carbide to graphite formation transition, by the use of an adequate experimental technique, able to measure real stable (Tst) and metastable (Tmst) eutectic temperatures. Have been used three ceramic cups for investigating thermal analysis: (i) for normal solidification; (ii) with addition of Te for Tmst measurement; (iii) with more inoculant addition for Tst measurement. As a general rule, measured values appear to be lower compared with calculated values (as chemical composition effects), with an average difference at 14.4 °C for Tst and 8.3 °C for Tmst. It is found a good relationship between the undercooling degree at the lowest eutectic temperature (ΔT1) and at the end of solidification (ΔT3), reported to measured Tmst. The free carbides formation (chill tendency) is in good relationship with the undercooling degree during the eutectic reaction, reported to measured Tmst, especially for thin and medium wall thickness castings. The real measured Tmst instead of calculated Tmst is compulsory for the thin wall castings production, very sensitive to carbides to graphite transition. In the present experimental conditions, no visible relationship appears to be between chill tendency and undercooling at the end of solidification (ΔT3).

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Application of cooling curve analysis in solidification pattern and structure control of grey cast irons

Cited by 8 publications

References 20 publications

Simultaneous thermal and contraction / expansion curves analysis for solidification control of cast irons

Simultaneous thermal and contraction / expansion curves analysis for solidification control of cast irons

Experimental assessment of the gray cast iron production by inoculant injection

Carbide to Graphite Transition Control by Thermal Analysis in Grey Cast Irons

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