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

Neacsu, Elena Loredana; Riposan, Iulian; Cojocaru, Ana; Stan, Stelian; Stan, Iuliana

doi:10.3390/met10080993

Cited by 4 publications

(3 citation statements)

References 26 publications

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“…These are generally present in minimal amounts as impurities in raw materials, but Ce and Mg are added to the melt during treatment. Neacsu et al (2020) compared the solidification of uninoculated and inoculated hypoeutectic grey cast irons with carbon equivalents (CEs) 3.7%-3.8% and concentrated on the carbide to graphite production propensity by using measured stable and metastable eutectic temperatures. According to Seidu and Ripos an (2011), higher undercooling before recalescence increases the risk of formation of carbides during the solidification and reduces the nodule count.…”

Section: Introductionmentioning

confidence: 99%

Analyzing the effect of inoculant addition on the solidification of ductile cast irons using thermal analysis

Sangame¹,

Reddy

Shinde

2022

WJE

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Purpose The final properties of ductile iron are decided by the inoculant processing while pouring the melt. The shape and size of nodules generated during solidification are of paramount importance in solidification of ductile cast iron. The purpose of this study is to examine the effect of different inoculant addition on the solidification of ductile cast iron melt through thermal analysis. Design/methodology/approach Thermal analysis has recently grown as a tool for modeling the solidification behavior of ductile cast irons. Iron properties will be predicted by analyzing the cooling curve patterns of the melts and predicting the related effectiveness of inoculant processing. In this study, thermal analysis is used to evaluate the need for inoculation. Findings The amount and type of inoculation will affect the amount of undercooling during the solidification of ductile cast iron. It is found that the addition of 0.1 to 0.4 Wt.% inoculant lowers the austenite dendrite formation starting temperature while increasing the eutectic freezing temperature. Microstructure analysis revealed that the addition of inoculation increases the nodule count from 103 to 242 nodules. The beneficial effects of inoculation are sustained by an improved graphitization factor, which shows the formation of graphite nodules in the second phase of the eutectic reaction. Originality/value The inoculation treatment has improved metallurgical occurrences such as carbide to graphite conversion, graphite microstructure control, graphite nodule count at the start of solidification and the last stage of solidification, which determines the soundness of casting. The foundry industry can follow these steps for monitoring the solidification of ductile iron castings.

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Section: Introductionmentioning

confidence: 99%

Analyzing the effect of inoculant addition on the solidification of ductile cast irons using thermal analysis

Sangame¹,

Reddy

Shinde

2022

WJE

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“…These conditions should include chemical composition of the casting alloy, casting temperature and speed, gating and feeding system, cooling rate, size of castings, composition of facing sand and heap sand moulding mixtures etc.). Different moulds [1][2][3][4][5][6][7][8][9][10] or common mould for two or more castings [11][12][13][14][15][16] are usually used for investigation and comparison of pilot and control castings, meaning the same preset conditions of the effect of external factors on investigated castings. It does not allow to cast simultaneously pilot and con-trol castings with common gating and feeding system (from one side) and with individual cooling procedures (from other side).…”

Section: Introductionmentioning

confidence: 99%

Use of experimental casting equipment for research of castings crystallized through individual cooling procedures

Gabelchenko¹,

Belov²,

Kidalov³

et al. 2022

cisisr

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The research is devoted to development of experimental foundry pattern equipment, allowing to obtain two or more castings in a sand-loam mould; these casting are crystallized via individual cooling procedures within structurally sensitive intervals (dendrite, eutectic crystallization and recrystallization). Influence of scale factor is excluded in this case and it makes possible to obtain control and pilot castings, which have equal sizes; influence of chemical composition is excluded as well, because all castings located in a mould have common gating and feeding system. It provides the same temperature and casting speed for two or more castings in one mould with different compositions and technological properties of moulding mixtures for each of the comparing castings. Thereby, variable cooling rate, which is individual for each casting obtained in the experimental mould, remains the main factor having influence on forming of structure, mechanical and operating properties of cast metal. Possibility of investigation of rise of mechanical and operating properties of castings owing to only adjusting of cooling rate without use of alloying and modification appears in this case. Increase of the cooling rate in local temperature-time crystallization intervals is provided by blowing with cooling gases which are fed in the mould via the stand (receiver). Retarding of cooling rate occurs as a result of mould heating during thermal oxidizing destruction of exothermal carbon-containing additives which are specially introduced in the facing layer of moulding mixture. It is necessary to mention that variation of cooling rate can be conducted via the procedures which are individual for each casting located in the experimental mould. Developed and fabricated experimental foundry equipment was used for testing of the concrete cooling procedures of thin-walled castings made of grey cast iron. Pressure of cooling compressed air, which was fed during the process, and amount of exothermal carbon-containing additive, which was introduced in composition of the facing layer of moulding mixture for pilot castings were varied. As a result, the efficient cooling procedure was selected; it allowed to rise tensile strength for the pilot casting by 13 %, to improve cast iron quality (quality index) by 23 % and to increase structure dispersity of primary austenite by 21 % without introduction of alloying elements and modifiers in cast iron composition.

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“…The casting process is not only used for cast iron, but also for non-ferrous materials [3][4][5][6][7]. Gray cast iron has flake -shaped graphite, while ductile cast iron has nodular graphite [8]. The formation of graphite is influenced by silicon; the more silicon the more graphite is formed [9].…”

Section: Introductionmentioning

confidence: 99%

Effect of Cooling Rate on Microstructure and Hardness in Gray Cast Iron Casting Process

Yulianto

Soenoko²,

Suprapto³

et al. 2021

Acta Metall Slovaca

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This study aims to investigate the thermal conditions of the molds, changes in microstructure and hardness of casting products using sand mold and permanent mold. The use of sand mold and permanent mold results in different cooling rates. Thermal analysis was performed using a thermocouple to obtain a temperature versus time curve. Metallographic observations were carried out using a Scanning Electron Microscope equipped with Energy-Dispersive X-ray Spectroscopy. The Vickers hardness test was carried out in three areas with different thicknesses. The results showed a constant temperature at 691 oC where the eutectoid phase reaction occurred. Testing with sand mold showed that cast iron with flake graphite was finer and spreader than graphite in cast iron produced by permanent mold. Meanwhile, gray cast iron from a casting process with a permanent mold has a higher hardness than gray cast iron from a casting process using a sand mold.

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

Cited by 4 publications

References 26 publications

Analyzing the effect of inoculant addition on the solidification of ductile cast irons using thermal analysis

Analyzing the effect of inoculant addition on the solidification of ductile cast irons using thermal analysis

Use of experimental casting equipment for research of castings crystallized through individual cooling procedures

Effect of Cooling Rate on Microstructure and Hardness in Gray Cast Iron Casting Process

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