Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 40
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

In modern times, there are increasing requirements for products quality in every part of manufacturing industry and in foundry industry it

is not different. That is why a lot of foundries are researching, how to effectively produce castings with high quality. This article is dealing

with search of the influence of using different types of risers or chills on shrinkage cavity production in ductile iron castings. Differently

shaped risers were designed using the Wlodawer´s modulus method and test castings were poured with and without combination of chills.

Efficiency of used risers and chills was established by the area of created shrinkage cavity using the ultrasound nondestructive method.

There are introduced the production process of test castings and results of ultrasound nondestructive reflective method. The object of this

work is to determine an optimal type of riser or chill for given test casting in order to not use overrated risers and thus increase the cost

effectiveness of the ductile iron castings production.

Go to article

Authors and Affiliations

I. Vasková
M. Hrubovčáková
M. Conev
Download PDF Download RIS Download Bibtex

Abstract

Austenitization is the first step of heat treatment preceding the isothermal quenching of ductile iron in austempered ductile iron (ADI)

manufacturing. Usually, the starting material for the ADI production is ductile iron with more convenient pearlitic matrix. In this paper we

present the results of research concerning the austenitizing of ductile iron with ferritic matrix, where all carbon dissolved in austenite must

come from graphite nodules. The scope of research includedcarrying out the process of austenitization at 900o

Cusing a variable times

ranging from 5 to 240minutes,and then observations of the microstructure of the samples after different austenitizing times. These were

supplemented with micro-hardness testing. The research showed that the process of saturating austenite with carbon is limited by the rate

of dissolution of carbon from nodular graphite precipitates.

Go to article

Authors and Affiliations

A. Krzyńska
A. Kochański
Download PDF Download RIS Download Bibtex

Abstract

In this study, a preliminary evaluation was made of the applicability ofthe signalsof the cutting forces, vibration and acoustic emission in

diagnosis of the hardness and microstructure of ausferritic ductile iron and tool edge wear rate during its machining. Tests were performed

on pearlitic-ferritic ductile iron and on three types of ausferritic ductile iron obtained by austempering at 400, 370 and 320⁰C for 180

minutes. Signals of the cutting forces (F), vibration (V) and acoustic emission (AE) were registered while milling each type of the cast iron

with a milling cutter at different degrees of wear. Based on individual signals from all the sensors, numerous measures were determined

such as e.g. the average or maximum signal value. It was found that different measures from all the sensors tested depended on the

microstructure and hardness of the examined material, and on the tool condition. Knowing hardness of the material and the cutting tool

edge condition, it is possible to determine the structure of the material .Simultaneous diagnosis of microstructure, hardness, and the tool

condition is probably feasible, but it would require the application of a diagnostic strategy based on the integration of numerous measures,

e.g. using neural networks.

Go to article

Authors and Affiliations

D. Myszka
S. Bombiński
Download PDF Download RIS Download Bibtex

Abstract

The paper presents the results of investigations of the growth of protective coating on the surface of ductile iron casting during the hot-dip

galvanizing treatment. Ductile iron of the EN-GJS-600-3 grade was melted and two moulds made by different technologies were poured to

obtain castings with different surface roughness parameters. After the determination of surface roughness, the hot-dip galvanizing

treatment was carried out. Based on the results of investigations, the effect of casting surface roughness on the kinetics of the zinc coating

growth was evaluated. It was found that surface roughness exerts an important effect on the thickness of produced zinc coating

Go to article

Authors and Affiliations

D. Kopyciński
E. Guzik
A. Szczęsny
Download PDF Download RIS Download Bibtex

Abstract

The paper discusses the reasons for the current trend of substituting ductile iron castings by aluminum alloys castings. However, it has been shown that ductile iron is superior to aluminum alloys in many applications. In particular it has been demonstrated that is possible to produce thin wall wheel rim made of ductile iron without the development of chills, cold laps or misruns. In addition it has been shown that thin wall wheel rim made of ductile iron can have the same weight, and better mechanical properties, than their substitutes made of aluminum alloys.

Go to article

Authors and Affiliations

M. Górny
E. Fraś
W. Kapturkiewicz
Download PDF Download RIS Download Bibtex

Abstract

The combination of the austempered ductile iron mechanical properties strongly depend on the parameters used on the austempering cycle. On this study, the influence of austempering time and austenitizing temperature on the properties of a ductile iron were evaluated. A metallic bath of Zamak at 380°C was used as an austempering mean. A set of ductile iron blocks were austenitized at 900°C for 90 minutes and submitted to different austempering times in order to determine the best combination of microstructural and mechanical properties. After the definition of the time of austempering, the reduction of the austenitizing temperature was evaluated. The best combination of properties was obtained with austenitizing at 860°C and austempering during 60 minutes.

Go to article

Authors and Affiliations

L. Pereira
M.R. Bellé
L.F. Seibel Júnior
W.M. Pasini
R.F. Do Amaral
V. Karlinski de Barcellos
Download PDF Download RIS Download Bibtex

Abstract

The excellent property combination of thin wall ductile iron castings (TWDI), including thin wall alloyed cast iron (e.g. austenitic TWDI) has opened new horizons for cast iron to replace steel castings and forgings in many engineering applications with considerable cost benefits. TWDI is considered as a potential material for the preparation of light castings with good mechanical and utility properties, the cost of which is relatively low. In this study, unalloyed and high Ni-alloyed (25% Ni) spheroidal graphite cast iron, with an austenitic metallic matrix were investigated. The research was conducted for thin-walled iron castings with 2, 3 and 5mm wall thickness, using different mould temperature (20°C, and 160°C) to achieve various cooling rates. The metallographic examinations i.e. characteristic of graphite nodules, metallic matrix, and primary grains of austenite dendrites (in high-nickel NTWDI) and mechanical properties were investigated. The study shows that homogeneity of the casting structure of thin-walled castings varies when changing the wall thickness and mould temperature. Finally, mechanical properties of thin-walled ductile iron castings with ferritic-pearlitic and austenitic metallic matrix have been shown.

Go to article

Authors and Affiliations

M. Górny
M. Kawalec
G. Witek
A. Rejek
Download PDF Download RIS Download Bibtex

Abstract

Changes of gas pressure in the moulding sand in the zone adjacent to mould cavity were analysed during pouring of cast iron. No significant effect of pressure on the surface quality of castings was observed. In the second series of tests, the concentration of hydrogen in the gas atmosphere was measured. It has been found that the value of this concentration depends on metal composition and is particularly high in cast iron containing magnesium. This is due to the reduction of water vapour with the element that has high affinity to oxygen. The presence of hydrogen causes the formation of gas-induced defects on the casting surface.

Go to article

Authors and Affiliations

A. Chojecki
J. Mocek
Download PDF Download RIS Download Bibtex

Abstract

The work presents the research results of the silumin coat structure applied on the carbidic alloy ductile iron with the metal matrix: pearlitic, bainitic and martensitic. The coats were made in the AlSi5 silumin bath at the temperature tk = 750±5°C. The holding time of cast iron element in the bath was τ = 180s. Irrespective of the kind of tested ductile iron the obtained coat consisted of three layers with a different phase composition. The first layer from the cast iron ground “g1`” is built from Fe4CSi carbide which contains selected alloy additives of the cast iron. On it the second layer “g1``” crystallizes. It consists of the AlFeSi inter-metallic phase which can appear in its pure form or contain a small quantity of the alloy additives of the cast iron. The last external part of the layer “g2” mainly consists of the hypo-eutectic phases of silumin. The AlFeSi inter-metallic phases in the form of free precipitations with a lamellar or faceted morphology can also appear there. These phases also can contain a small quantity of the alloy additives of the cast iron. More than that, in all the layers of the coat there are graphite precipitations. The phenomenon of graphite movement to the coat is caused by intensive dissolving of the cast iron element surface by the aluminum of the silumin bath.

Go to article

Authors and Affiliations

T. Szymczak
Download PDF Download RIS Download Bibtex

Abstract

The paper presents recent developments concerning the formation of surface layer in austempered ductile iron castings. It was found that the traditional methods used to change the properties of the surface layer, i.e. the effect of protective atmosphere during austenitising or shot peening, are not fully satisfactory to meet the demands of commercial applications. Therefore, new ways to shape the surface layer and the surface properties of austempered ductile iron castings are searched for, to mention only detonation spraying, carbonitriding, CVD methods, etc.

Go to article

Authors and Affiliations

D. Myszka
Download PDF Download RIS Download Bibtex

Abstract

The presence of the chunky graphite is unwanted in the cast iron with the spheroidal graphite for this significantly lowers the properties of

the ductile iron. This shape of the graphite is formed as the result of the slow cooling rate of the castings with large thermal point and also

due to the presence of the elements which suppress the formation of the spheroidal graphite and support formation of the chunky graphite.

The spheroidal graphite present in the ductile iron assures the excellent mechanical properties, while the chunky graphite significantly

reduces those properties of the ductile iron. Therefore it is of importance to assume conditions under which prevented is the formation of

the chunky graphite. The casts were carried out under the conditions of the regular operation of the foundry and tested were various types

of modifiers and inoculators and also pre-inoculators containing the elements suppressing the formation of the chunky graphite (Al, Sb a

Ba). Applied were also the chromium breaker core to suppress the formation chunky graphite which was present in the structure in the

places after the feeders elimination. As whole, executed were eight casts with various types of the modifiers and inoculators.

Go to article

Authors and Affiliations

P. Futas
Download PDF Download RIS Download Bibtex

Abstract

The paper attempts to analyze distortions of cast iron and cast steel rings, after heat treatment cycles. The factors influencing distortion are: chemical composition of material, sample geometry, manufacturing process, hardenability, temperature and heat treatment method. Standard distortion tests are performed on C-ring samples. We selected a ring-model, which approximate the actual part, so that findings apply to gear rings. Because distortion depends on so many variables, this study followed strictly defined procedures. The research was started by specifying the appropriate geometry of the samples. Then, the heat treatment was conducted and samples were measured again. The obtained results allow to determine the value of the resulting distortion and their admissibility. The research will be used to evaluate the possibility of using the material to produce parts of equipment operated under extreme load conditions.

Go to article

Authors and Affiliations

P. Nawrocki
K. Łukasik
J. Misiak
D. Myszka
Download PDF Download RIS Download Bibtex

Abstract

Studies were conducted on a zinc coating produced on the surface of ductile iron grade EN-GJS-500-7 to determine the eutectic grain

effect. For this purpose, castings with a wall thickness of 5 to 30 mm were made and the resulting structure was examined. To obtain a

homogeneous metal matrix, samples were subjected to a ferritising annealing treatment. To enlarge the reaction surface, the top layer was

removed from casting by machining. Then hot dip galvanising treatment was performed at 450°C to capture the kinetics of growth of the

zinc coating (in the period from 60 to 600 seconds). Analysing the test results it was found that within the same time of hot dip

galvanising, the differences in the resulting zinc coating thickness on samples taken from castings with different wall cross-sections were

small but could, particularly for shorter times of treatment, reduce the continuity of the alloyed layer of the zinc coating.

Go to article

Authors and Affiliations

D. Kopyciński
E. Guzik
A. Szczęsny
Download PDF Download RIS Download Bibtex

Abstract

The conducted work shows and confirms how thermal analysis of grey and ductile iron is an important source for calculating metallurgical data to be used as input to increase the precision in simulation of cooling and solidification of cast iron. The aim with the methodology is to achieve a higher quality in the prediction of macro– and micro porosity in castings. As comparison objects standard type of sampling cups for thermal analysis (solidification module M ≈ 0.6 cm) is used. The results from thermal analysis elaborated with the ATAS MetStar system are evaluated parallel with the material quality (including tendency to external and internal defects) of the tested specimen. Significant temperatures and calculated quality parameters are evaluated in the ATAS MetStar system and used as input to calibrate the density curve as temperature function in NovaFlow&Solid simulation system. The modified data are imported to the NovaFlow&Solid simulation system and compared with real results.

Go to article

Authors and Affiliations

P-E. Persson
Z. Ignaszak
H. Fransson
V. Kropotkin
R. Andersson
A. Kump
Download PDF Download RIS Download Bibtex

Abstract

Stereological description of dispersed microstructure is not an easy task and remains the subject of continuous research. In its practical aspect, a correct stereological description of this type of structure is essential for the analysis of processes of coagulation and spheroidisation, or for studies of relationships between structure and properties. One of the most frequently used methods for an estimation of the density Nv and size distribution of particles is the Scheil - Schwartz – Saltykov method. In this article, the authors present selected methods for quantitative assessment of ductile iron microstructure, i.e. the Scheil - Schwartz – Saltykov method, which allows a quantitative description of three-dimensional sets of solids using measurements and counts performed on two-dimensional cross-sections of these sets (microsections) and quantitative description of three-dimensional sets of solids by X-ray computed microtomography, which is an interesting alternative for structural studies compared to traditional methods of microstructure imaging since, as a result, the analysis provides a three-dimensional imaging of microstructures examined.
Go to article

Authors and Affiliations

B. Mrzygłód
P. Matusiewicz
A. Tchórz
I. Olejarczyk-Wożeńska
Download PDF Download RIS Download Bibtex

Abstract

The paper presents the optimization of master alloy amount for the high nodular graphite yield (80-90%) in cast iron obtain in lost foam process. The influence of the gating system configuration and the shape of the reaction chamber, the degree of spheroidisation cast iron was examined. Research has shown that the, optimal of master alloy amount of 1.5% by mass on casting iron. The degree of spheroidisation is also influenced by the gating system configuration. The best spheroidisation effect was obtained for liquid cast iron was fed into the reaction chamber from the bottom and discharged from the top.
Go to article

Authors and Affiliations

P. Just
T. Pacyniak
R. Kaczorowski
Download PDF Download RIS Download Bibtex

Abstract

In sand moulds, at a distance of 3 mm from the metal- mould interface, the sensors of temperature, and of oxygen and hydrogen content were installed. Temperature and the evolution of partial gas pressure have been analysed in moulds bonded with bentonite with or without the addition of seacoal, water glass or furan resin. Moulds were poured with ductile iron. For comparison, also tests with the grey iron have been executed. It was found that the gas atmosphere near the interface depends mainly on the content of a carbonaceous substance in the mould. In the green sand moulds with 5% of seacoal or bonded with furan resin, after the mould filling, a sudden increase in the hydrogen content and the drop of oxygen is observed. This gas evolution results from the oxidation of carbon and reduction of water vapour in the mould material, and also from the reduction of water vapour and alloy reoxidation. In carbon-free sand, the evolution in the gas composition is slower because water vapour is reduced only at the interface. Changes of oxygen and hydrogen content in the controlled zone are determined by the transport phenomena.

Go to article

Authors and Affiliations

J. Mocek
A. Chojecki
Download PDF Download RIS Download Bibtex

Abstract

In this paper, the effect of changes the parameters of heat treatment on the structure and the degree of elements segregation was

determined, in the context of corrosion resistance of ductile iron Ni-Mn-Cu, containing 7.2% Ni, 2.6% Mn and 2.4% Cu. In the condition

after casting, castings of austenitic matrix and 160HBW hardness were obtained. The achieved castings were soaked at 450, 550 and

650°C for 4, 8 and 12 hours, then cooled down at the ambient air. In most cases, the heat treatment resulted in a change in the castings

matrix, had the consequence of increasing their hardness in comparison to raw castings. Increasing the temperature and prolonging soaking

time resulted in increasing the degree of transformation of austenite, while reducing the degree of elements segregation. This led to the

formation of slightly bigger number of pitting due to corrosion, but not so deep and more evenly distributed in comparison to raw castings.

Wherein the results of corrosion tests show that heat treatment of castings did not significantly change their corrosion resistance in

comparison to raw castings, in contrast to the significant increase in mechanical properties.

Go to article

Authors and Affiliations

M. Stachowicz
A. Janus
D. Medyński
Download PDF Download RIS Download Bibtex

Abstract

In the family of iron-based alloys, ductile iron enjoys the highest rate of development, finding application in various industries. Ductile iron or the cast iron with spheroidal graphite can be manufactured by various methods. One of them is the Inmold spheroidization process characterized by different technological solutions, developed mainly to increase the process efficiency. So far, however, none of the solutions has been based on the use of a reactor made outside the casting mould cavity. The method of spheroidization inside the casting mould using a reaction chamber developed at the Foundry Research Institute is an innovative way of cast iron treatment. The innovative character of this method consists in the use of properly designed and manufactured reactor placed in the casting mould cavity. Owing to this solution, the Inmold process can be carried out in moulds with both horizontal and vertical parting plane. The study presents the results of examinations of the microstructure of graphite precipitates and metal matrix of castings after spheroidization carried out by the Inmold process using a reactor and mould with vertical parting plane. Special pattern assembly was made for the tests to reproduce plates with wall thicknesses of 3; 5; 7; 10; 20 and 30 mm. The content of residual magnesium was determined for all tested castings, while for castings of plates with a wall thickness equal to or larger than 10 mm, testing of mechanical properties was additionally performed.

Go to article

Authors and Affiliations

J. Kamińska
M. Angrecki
Z. Stefański
A. Palma
Download PDF Download RIS Download Bibtex

Abstract

The results presented in this paper are a continuation of the previously published studies. The results of hest treatment of ductile iron with

content 3,66%Si and 3,80% Si were produced. The experimental castings were subjected to austempering process for time 30, 60 and 90

minutes at temperature 300o

C. The mechanical properties of heat treated specimens were studied using tensile testing and hardness

measurement, while microstructures were evaluated with conventional metallographic observations. It was again stated that austempering

of high silicone ferritic matrix ductile iron allowed producing ADI-type cast iron with mechanical properties comparable with standard

ADI.

Go to article

Authors and Affiliations

A. Krzyńska
A. Kochański
Download PDF Download RIS Download Bibtex

Abstract

Image analysis allows to acquire a number of valuable quantitative informations on the observed structure and make appropriate conclusions. So far, a large part of analyzed images came only from light microscopes, where it was a possibility of accurately distinguish the different phases on the plane. However, the problem happened in the case of the observation of images obtained by scanning electron microscopy. In this case, the presence of various shades of gray, and the spaciousness of the image attained. To perform the analysis the matrix images of the ausferritic ductile iron were used. Full analysis was carried out using the computer program MicroMeter 1.03. Results obtained in the analysis were related directly to the results from X-ray diffraction. Obtained as a result of the analysis were related directly to the results from X-ray diffractometer. The following technique has weaknesses, including the misinterpretation by the operator microscope or program. After all, it was possible to obtain similar results to the result that has been obtained from X-ray diffractometer.
Go to article

Authors and Affiliations

W. Trzaskowski
P. Nawrocki
K. Łukasik
D. Myszka
Download PDF Download RIS Download Bibtex

Abstract

Production of spheroidal graphite cast iron is today quite mastered technology. There are many methods achieving the nodular graphite morphology. Each of these methods have specific characteristics and requirements to technical support, properties and the type of applied modifier. Selection of the spheroidization method is dependent on foundry disposition, production character, economic balance, quality requirements, etc. In case of centrifugally casting the core, which fills body and neck of the roll, is created by ductile iron. Considering the sophisticated production of centrifugally cast rolls for hot rolling mills it is necessary to ensure a high reproducibility and reliability of ductile cast iron production quality in the bulk range of 9-18 t per tapping. These conditions are in the Roll Foundry in Vítkovicke Slevarny, spol. s r.o. provided and verified mastered overpour method and the newly injection of cored wire in the melt.

Go to article

Authors and Affiliations

T. Válek
P. Šimon
L. Střílková
Download PDF Download RIS Download Bibtex

Abstract

An intentional change in material properties is an important condition for castings production. It is one way how to meet the casting requirements of how to adapt the material properties to the operating conditions. Centrifugally cast rolls are multi-layer rollers, castings. The working layer of the barrel is called the "shell" and the body of the roll and the necks rolls are called "core". The article deals with the influence of the properties of the core iron. Earlier laboratory experiments were primary analysed for metallographic analysis and mechanical properties. These data were compared back to the experiments. The results of these laboratory working were later applied in the operating conditions of the roll foundry Vítkovitcké slévárny, spol. s r.o. The spun cast roll produced with the applied metallurgical processing change was supplied to the hot strip mill. There were monitored the positive effect of the change of the metallurgical process of the production of the core iron on the useful properties of the centrifugally cast roll. The experiment was done in order to increase the mechanical properties of ductile pearlite ductile iron. The copper in these core iron material increases the hardness and strength primarily.
Go to article

Authors and Affiliations

J. Hampl
T. Válek
T. Hýbl
Download PDF Download RIS Download Bibtex

Abstract

The article contains the results of tests performed under the target project in Hardtop Foundry Charsznica. The objective of the tests and studies was to develop a technology of making high-quality ductile iron castings, combined with effective means of environmental protection. The studies presented in this article related to castings weighing from 1 to 300 kg made from ductile iron of grades 400-15 and 500-7, using two-layer moulds, where the facing and core sand was the sand with an alkaline organic binder, while backing sand was the sand with an inorganic geopolymer binder. A simplified method of sand reclamation was applied with possible reuse of the reclaim as an addition to the backing sand. The cast iron spheroidising treatment and inoculation were selected taking into account the specific conditions of Hardtop Foundry. A pilot batch of castings was made, testing the gating and feeding systems and using exothermic sleeves on risers. The study confirmed the validity of the adopted concept of making ductile iron castings in layer moulds, while maintaining the content of sand with an organic binder at a level of maximum 15%.
Go to article

Authors and Affiliations

M. Rączka
K. Gandurski
B. Isendorf

This page uses 'cookies'. Learn more