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.

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 Influence of Technological Parameters of Furane Mixtures on Shrinkage Creation in Ductile Cast Iron Castings

2014 ◽  
Vol 59 (3) ◽  
pp. 1037-1040 ◽  
Author(s):  
I. Vasková ◽  
M. Hrubovčáková ◽  
J. Malik ◽  
Š. Eperješi
Keyword(s):  
Cast Iron ◽  
Ductile Iron ◽  
Ductile Cast Iron ◽  
Gating System ◽  
Technological Parameters ◽  
Iron Castings ◽  
Steel Castings ◽  
The Impact ◽  
Very High ◽  
Great Development

Abstract Ductile cast iron (GS) has noticed great development in last decades and its boom has no analogue in history humankind. Ductile iron has broaden the use of castings from cast iron into areas, which where exclusively domains for steel castings. Mainly by castings, which weight is very high, is the propensity to shrinkage creation even higher. Shrinkage creation influences mainly material, construction of casting, gating system and mould. Therefore, the main realized experiment was to ascertain the influence of technological parameters of furane mixture on shrinkage creation in castings from ductile iron. Together was poured 12 testing items in 3 moulds forto determine and compare the impact of various technological parameters forms the propensity for shrinkage in the casting of LGG.

Notch Effects on Impact and Bending Characteristics of Spheroidal Graphite and Compacted Vermicular Graphite Cast Irons with Various Matrices

2010 ◽  
Vol 457 ◽  
pp. 392-397 ◽  
Author(s):  
Tohru Nobuki ◽  
Minoru Hatate ◽  
Toshio Shiota
Keyword(s):  
Cast Iron ◽  
Transition Temperature ◽  
Brittle Fracture ◽  
Cast Steel ◽  
Charpy Impact ◽  
Spheroidal Graphite ◽  
Buffer Effect ◽  
Cast Irons ◽  
Type Specimens ◽  
The Impact

The object of this study is to find out and evaluate systematically how the basic factors such as graphite-shape, external notch and matrix-characteristic affect the impact and bending characteristics of cast irons. The Spheroidal Graphite (SG) and Compacted Vermicular graphite (CV) cast iron samples were prepared, and their matrixes were modified into ferritic, pearlitic and bainitic in order to make the various kinds of samples whose graphite-shape and matrix vary widely. From each sample we produced five kinds of Charpy-type specimens by adding five kinds of notches whose stress concentration factor (α) varied from 1.0 (un-notched) to 4.8. The Charpy impact value decreases greatly in the range of α from 1 to 2.3 but decreases slightly in the range of α larger than 2.3. No influence to the fracture energy in the range of α larger than 2.3. Increasing of α results in moderate elevation of transition temperature of Charpy impact value and the transition temperature of CV cast ion is lower than that of SG one. The impact value in brittle fracture region of the cast iron samples were recognized to be a little bit larger than that of cast steel sample, and it was considered to be caused by graphite which act as a kind of buffer effect against crack growth in brittle fracture.

scholarly journals Synergy of Practical Knowledge of Molding Sands Reclamation in Heavy Casting Foundry of Iron Alloys

2013 ◽  
Vol 13 (3) ◽  
pp. 30-36 ◽  
Author(s):  
Z. Ignaszak ◽  
J-B. Prunier
Keyword(s):  
Cast Iron ◽  
Practical Knowledge ◽  
Cast Steel ◽  
Iron Alloys ◽  
Thermal Regeneration ◽  
Molding Sand ◽  
Iron Castings ◽  
Dynamic Phenomena

Abstract The paper summarizes research realized by the author in laboratory and industrial conditions (foundries of cast steel and cast iron, castings up to 50 tons) on the effects of the chemically hardened molding sands regeneration using hard/soft rubbing in the dry reclamation. A reference was simultaneously made to advisability of application of the thermal regeneration in conditions, where chromite amount in the circulating (reclaimed) molding sand goes as high as above ten percent. An advisability of connecting standard and specialized methods of examination of the reclaimed sands and molding sands made using it was pointed out. A way of application of studies with the Hot Distortion Plus® method modified by the author for validation of modeling of the thermo-dynamic phenomena in the mold was shown.

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.

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.

ISO 185/JL/350

Alloy Digest ◽  
2021 ◽  
Vol 70 (9) ◽  
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Cast Iron ◽  
Gray Cast Iron ◽  
High Strength ◽  
Heat Treating ◽  
Gray Cast ◽  
Spheroidal Graphite ◽  
Cast Irons ◽  
Test Pieces

Abstract ISO 185/JL/350 is a higher-tensile-strength gray cast iron that has a pearlitic matrix, and a tensile strength of 350–450 MPa (51–65 ksi), when determined on test pieces machined from separately cast, 30 mm (1.2 in.) diameter test bars. It provides a combination of high strength while still maintaining good thermal conductivity compared with other types of cast iron. This grade approaches the maximum tensile strength attainable in gray cast iron. Applications therefore tend to be confined to those where thermal conductivity requirements in service preclude the use of one of the other higher-strength materials such as spheroidal graphite cast irons, which have inferior thermal properties. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on wear resistance as well as casting and heat treating. Filing Code: CI-85. Producer or source: International Organization for Standardization.

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