scholarly journals INVESTIGATION OF CARBON INFLUENCE IN CROMIUMIUM CAST IRONS FOR FORMING CASTINGS IN SAND AND COMBINED MOLDS

2018 ◽  
pp. 41-46
Author(s):  
E. I. Marukovich ◽  
V. M. Iljushenko ◽  
V. A. Pumpur ◽  
V. M. Andrienko
Keyword(s):  
Cast Iron ◽  
Carbon Content ◽  
Experimental Studies ◽  
Cast Irons ◽  
Its Analysis ◽  
Numerical Studies ◽  
Iron Castings ◽  
Hardening Process ◽  
Kinetics Of

The results of research to determine the influence of the amount of carbon in chromium cast irons on the formation of castings in sand and combined molds are described in the article. Experimental studies were carried out with casting samples from wearresistant cromium cast iron with different carbon contents. The microstructure of the obtained samples is presented, and its analysis is performed. Numerical studies have been carried out to evaluate the effect of the carbon content on the dynamics and kinetics of hardening of castings in sand and combined molds. The influence of the carbon content on the hardening process of cromium cast iron castings during foundry casting in sand and combined molds is established. The results of the research were used for the manufacture parts of crushing and grinding equipment.

scholarly journals Discussion on Usability of the Niyama Criterion for Porosity Predicting in Cast Iron Castings

2017 ◽  
Vol 17 (3) ◽  
pp. 196-204 ◽  
Author(s):  
Z. Ignaszak
Keyword(s):  
Cast Iron ◽  
Cast Steel ◽  
Experimental Studies ◽  
Post Processing ◽  
Cast Irons ◽  
Niyama Criterion ◽  
Iron Castings ◽  
Steel Castings ◽  
Shrinkage Compensation ◽  
Simulation Codes

Abstract The paper refers to previous publications of the author, focused on criteria of casting feeding, including the thermal criterion proposed by Niyama. On the basis of this criterion, present in the post-processing of practically all the simulation codes, danger of casting compactness (in the sense of soundness) in form of a microporosity, caused by the shrinkage phenomena, is predicted. The vast majority of publications in this field concerns shrinkage and feeding phenomena in the cast steel castings – these are the alloys, in which parallel expansion phenomenon does not occur as in the cast irons (graphite crystallization). The paper, basing on the simulation-experimental studies, presents problems of usability of a classic, definition-based approach to the Niyama criterion for the cast iron castings, especially of greater massiveness, for prediction of presence of zones of dispersed porosity, with relation to predictions of the shrinkage type defects. The graphite expansion and its influence on shrinkage compensation during solidification of eutectic is also discussed.

First Stage Graphitization of Subcritically Treated White Cast Iron

1984 ◽  
Vol 34 ◽  
Author(s):  
A. A. Hussein ◽  
L. I. El-Menawati ◽  
M. A. Kassem ◽  
B. I. Yostos
Keyword(s):  
Cast Iron ◽  
Uniform Distribution ◽  
White Cast Iron ◽  
Practical Significance ◽  
Cast Irons ◽  
Nucleation Sites ◽  
Diffusion Paths ◽  
The Creation ◽  
Kinetics Of ◽  
Scanning Electron

ABSTRACTThe kinetics of first stage graphitization was studied in white cast irons of different compositions. These irons were presubjected to various isothermal anneals at 300–500°C, after being step-quenched from the intercritical (austenite and carbide) region. As a consequence of such pretreatment, the kinetics of post first stage graphitization were substantially accelerated. Both light and scanning electron metallography hive indicated that such acceleration arises due to the creation of vast areas of austenite/carbide interfaces upon cooling to and during subcritical transformations. These interfaces act as favourable nucleation sites for graphite and additionally they provide shorter diffusion paths for carbon. The latter also allows faster growth of graphite nodules. Effects of varying Si and Hn contents of the cast iron were determined. The practical significance of such treatment in providing] faster malleabilization and uniform distribution of graphite nodules is thus evident.

scholarly journals The performance properties of chromium cast irons with different degree of eutectic

2019 ◽  
pp. 50-54
Author(s):  
E. I. Marukovich ◽  
V. M. Ilyushenko ◽  
G. P. Korotkin ◽  
P. Yu. Duvalov ◽  
V. M. Andrienko ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
Heat Exchange ◽  
Carbon Content ◽  
Cast Irons ◽  
Performance Properties ◽  
Primary Carbides ◽  
Large Primary

The influence of carbon and the type of forms on the wear resistance, hardness and strength of samples from chromium iron made of ИЧХ18ВМ cast iron was investigated. The analysis of the structural structure of the samples of cast iron ИЧХ18ВМ depending on the type of shape and amount of carbon was made. It is established that regardless of the type of forms with increasing carbon content the formation of large primary carbides is observed, and then the emergence of particularly large trigonal carbides in a hypereutectic iron was confirmed. It is shown that regardless of the type of forms the formation and growth of carbides are influenced by such factors as an increase in the carbon content and the rate of solidification. A comparison was made between the hardness, strength, and wear resistance of samples obtained at different heat exchange and solidification rates.

ANALISA KETAHANAN AUS BESI COR EN-JN2019 DENGAN METODE FACTORIAL DESIGN TERHADAP UNSUR PADUAN DAN LAJU PENDINGINAN

2016 ◽  
Vol 6 (1) ◽  
pp. 11
Author(s):  
Kus Hanaldi
Keyword(s):  
Cast Iron ◽  
Factorial Design ◽  
Cast Irons ◽  
Wear Resistant

Salah satu material yang dapat digunakan pada kondisi lingkungan abrasif adalah white cast irons atau abrasion-resistant cast iron. EN-JN2019 adalah salah satu jenis besi cor yang dapat digunakan pada kondisi ini. Pada besi cor  ini terkandung unsur karbon, silikon, mangan, dan chromium. Analisa ketahanan aus material ini telah dilakukan dengan menggunakan factorial design terhadap dua kombinasi kandungan chromium (1% dan 2%), dua kombinasi kandungan silikon (1% dan 1,5%) dan dua kombinasi ketebalan sampel (5mm dan 30mm). Ketebalan sampel merupakan representasi dari laju pendinginan. Kajian terhadap kekerasan, struktur mikro, uji impact dan uji aus dari delapan sampel yang dihasilkan dari proses pengecoran telah dilaksanakan pula. Hasil pengujian kekerasan menunjukkan bahwa kekerasan menurun dengan meningkatnya ketebalan dan disertai dengan perubahan struktur mikro sebagai hasil dari laju pendinginan yang semakin lambat. Penambahan kandungan chromium meningkatkan kekerasan karena adanya pembentukan karbida. Penambahan kandungan silikon menurunkan kekerasan akibat pembentukan grafit yang lebih mudah. Pengaruh kandungan chromium dan silikon terhadap kekerasan memiliki ketergantungan  satu  dengan  lainnya,  karena  penambahan  silikon  menekan  pertumbuhan  karbida.  Dari  hasil pengujian impact didapatkan hasil, pada semua variasi chromium, silikon dan ketebalan tidak memiliki pengaruh terhadap harga impact. Sedangkan dari hasil pengujian keausan  didapatkan bahwa kekerasan  berbanding lurus dengan nilai wear resistant, semakin tinggi kekerasan maka nilai wear resistant akan semakin meningkat.Kata kunci: ketahanan aus, EN-JN2019, kandungan chromium, kandungan silikon, laju pendinginan, factorial design, pembentukan karbida.

scholarly journals Solidification Pattern of Si-Alloyed, Inoculated Ductile Cast Irons, Evaluated by Thermal Analysis

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 846
Author(s):  
Iuliana Stan ◽  
Denisa Anca ◽  
Stelian Stan ◽  
Iulian Riposan
Keyword(s):  
Cast Iron ◽  
Eutectic Reaction ◽  
Influencing Factor ◽  
Cooling Curve ◽  
Major Influence ◽  
Cast Irons ◽  
Minor Elements ◽  
Si Content ◽  
Si Effect ◽  
Positive Effect

The solidification cooling curve itself as well as its first derivative, and related temperatures, reported to the calculated equilibrium temperatures in stable and metastable solidification systems, are used to predict the solidification characteristics of the cast iron. Silicon, as the most representative cast iron element, and inoculation, as graphitizing metallurgical treatment, have a major influence on the transition from the liquid to the solid state. Six experimental programs are performed, with Si content typically for non-alloyed (<3.0% Si), low (3.0–3.5% Si) and medium alloyed (4.5–5.5% Si) ductile cast irons, as Si-content increasing, and inoculation simultaneous effects. Silicon is an important influencing factor, but the base and minor elements also affect the equilibrium eutectic temperatures, much more in the Fe-C-Si-Xi stable system (15–20 °C) than in the metastable system (5–10 °C), comparing with their calculation based only on a Si effect (Fe-C-Si system). The highest positive effect of inoculation is visible in non-Si alloyed cast irons (2.5% Si): 9–15 °C for the eutectic reaction and 3 to 4 times increased at the end of solidification (37–47 °C). Increased Si content decreases inoculation power to 7–9 °C for low alloying grade (up to 3.5% Si), with the lowest contribution at more than 4.5% Si (0.3–2.0 °C). 2.5–3.5% Si ductile cast irons are more sensitive to high solidification undercooling, especially at the end of solidification (but with a higher efficiency of inoculation), compared to 4.5–5.5% Si ductile cast irons, at a lower undercooling level, and at lower inoculation contribution, as well.

scholarly journals Management of the activity of quality assurance of cast iron castings in foundries

2021 ◽  
Vol 1781 (1) ◽  
pp. 012050
Author(s):  
A Josan ◽  
E Ardelean ◽  
M Ardelean ◽  
V Puţan
Keyword(s):  
Quality Assurance ◽  
Cast Iron ◽  
Iron Castings

scholarly journals Ce-Bearing FeSi Alloy Inoculation of Electrically Melted, Low Sulphur Grey Cast Irons for Thin Wall Castings

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1122
Author(s):  
Irina Varvara Balkan ◽  
Iulian Riposan
Keyword(s):  
Wall Thickness ◽  
Structural Characteristics ◽  
Cooling Curve ◽  
Thin Wall ◽  
Cast Irons ◽  
Iron Castings ◽  
Grey Cast ◽  
The Difference ◽  
Thermal Cooling ◽  
Fesi Alloy

Electrically melted and over-heated (>1500 °C) grey cast iron at less than 0.04%S, as commonly used, solidifies large amounts of carbides and/or undercooled graphite, especially in thin wall castings; this is necessary to achieve a stronger inoculation. The efficiency of Ce-bearing FeSi alloy is tested for lower ladle addition rates (0.15 and 0.25 wt.%), compared to the base and conventional inoculated iron (Ba,Ca-bearing FeSi alloy). The present work explores chill and associated structures in hypoeutectic grey iron (3.6–3.8%CE, 0.02%S, (%Mn) × (%S) = 0.013–0.016, Alres < 0.002%), in wedge castings W1, W2 and W3 (ASTM A 367, furan resin sand mould), at a lower cooling modulus (1.1–3.5 mm) that is typically used to control the quality of thin wall iron castings. Relatively clear and total chill well correlated with the standard thermal (cooling curve) analysis parameters and structural characteristics in wedge castings, at different wall thickness, displayed as the carbides/graphite ratio and presence of undercooled graphite morphologies. The difference in effects of the two inoculants addition is seen as the ability to decrease the amount of carbides and undercooled graphite, with Ce-bearing FeSi alloy outperforming the conventional inoculant, especially as the wall thickness decreased. It appears that Ce-bearing FeSi alloy could be a solution for low sulphur, electric melt, thin wall iron castings production.

Effect of Minor Additives on First Stage Graphitisation in White Cast Iron

1984 ◽  
Vol 34 ◽  
Author(s):  
P. L. Roy ◽  
A. K. Chakrabart ◽  
P. Banerjee
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Sodium Chloride ◽  
Yield Strength ◽  
White Cast Iron ◽  
Elemental Sulphur ◽  
Optimum Dose ◽  
White Iron ◽  
Kinetics Of ◽  
Strength And Ductility

ABSTRACTMinor additions (0.05-0.2 wt.%) of sodium chloride, hexachloroethane and elemental sulphur to commercial white iron melts have been found to enhance the kinetics of first stage graphitisation during subsequent annealing of white iron samples. The optimum dose of sodium chloride and hexachloroethane addition is around 0.1%. Yield strength and ductility of annealed test bars treated with NaCl or C2Cl6 compare favourably with those of untreated test bars. Sulphur treatment causes slight deterioration in mechanical properties. Fully grown nodules in both treated and untreated samples appear porous under SEM. Possible mechanisms of acceleration of graphitisation in the treated samples have been suggested.

scholarly journals The Joint Effects of Nitriding and Parameters Related to the Destabilisation of Austenite on Wear Resistance in White Cast Iron with 25% Cr

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 85
Author(s):  
Alejandro González-Pociño ◽  
Florentino Alvarez-Antolin ◽  
Juan Asensio-Lozano
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
White Cast Iron ◽  
Nitrided Layer ◽  
Erosive Wear ◽  
Air Cooling ◽  
Cast Irons ◽  
Eutectic Carbides ◽  
Noticeable Increase ◽  
Ionic Nitriding

In this article, the effects of an ionic nitriding treatment are analysed, together with deliberate variation of different thermal parameters associated with the destabilisation of austenite, on erosive wear resistance of white cast irons with 25% Cr. The methodology followed in this research was an experimental design, where six factors were analyzed by performing eight experiments. The thickness of the nitrided layer is much smaller than in white cast iron with lower percentages in Cr, never reaching 20 microns. The nitriding treatment entails considerable softening of the material underneath the nitriding layer. This softening behaviour becomes partially inhibited when the destabilisation temperature of austenite is 1100 °C and dwell times at such temperature are prolonged. This temperature seems to play a significant role in the solubilization of non-equilibrium eutectic carbides, formed during industrial solidification. The nitriding treatment leads to additional hardening, which, in these cases, favours a second destabilisation of austenite, with additional precipitation of secondary carbides and the transformation of retained austenite into martensite. Despite softening of the material, the nitriding treatment, together with air-cooling after destabilisation of the austenite, allows a noticeable increase in resistance to erosive wear.

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