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Number of results: 14
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Abstract

The presented article concerns the issue of supporting the ADI cast iron product manufacturing process and presents an IT system dedicated mainly to designers and technologists. Designers can be supported at the stage of selecting types of materials and technologies (including ADI cast iron) to produce products with required properties. Technologists can obtain support in determining the parameters (temperature and chemical) of the ADI cast iron manufacturing process in order to obtain products with specific properties. The system also contains an information resources (standards, documentation, examples) concerning ADI cast iron and products made of it. Examples of use by individual system users are presented as a case study.
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Authors and Affiliations

A. Opaliński
1
ORCID: ORCID
D. Wilk-Kołodziejczyk
1 2
ORCID: ORCID

  1. AGH University of Science and Technology, Al. A. Mickiewicza 30, 30-059 Krakow, Poland
  2. Łukasiewicz Research Network – Krakow Institute of Technology, 73 Zakopiańska Str., 30-418 Kraków, Poland
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Abstract

The structure of Austempered Ductile Iron (ADI) is depend of many factors at individual stages of casting production. There is a rich literature documenting research on the relationship between heat treatment and the resulting microstructure of cast alloy. A significant amount of research is conducted towards the use of IT tools for indications production parameters for thin-walled castings, allowing for the selection of selected process parameters in order to obtain the expected properties. At the same time, the selection of these parameters should make it possible to obtain as few defects as possible. The input parameters of the solver is chemical composition Determined by the previous system module. Target wall thickness and HB of the product determined by the user. The method used to implement the solver is the method of Particle Swarm Optimization (PSO). The developed IT tool was used to determine the parameters of heat treatment, which will ensure obtaining the expected value for hardness. In the first stage, the ADI cast iron heat treatment parameters proposed by the expert were used, in the next part of the experiment, the settings proposed by the system were used. Used of the proposed IT tool, it was possible to reduce the number of deficiencies by 3%. The use of the solver in the case of castings with a wall thickness of 25 mm and 41 mm allowed to indication of process parameters allowing to obtain minimum mechanical properties in accordance with the PN-EN 1564:2012 standard. The results obtained by the solver for the selected parameters were verified. The indicated parameters were used to conduct experimental research. The tests obtained as a result of the physical experiment are convergent with the data from the solver.
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Authors and Affiliations

K. Jaśkowiec
1 2
ORCID: ORCID
A. Opaliński
2
ORCID: ORCID
P. Kustra
2
D. Jach
3
D. Wilk-Kołodziejczyk
1 2
ORCID: ORCID

  1. Lukasiewicz Research Network-Krakow Institute of Technology, Poland
  2. AGH University of Science and Technology, Department of Applied Computer Science and Modelling, Poland
  3. Kutno Foundry, Poland
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Abstract

In the case of mining machines, tribocorrosion damage is often observed. This type of consumption is caused by the joint action of mining environment factors such as abrasive and water. The search for methods to counteract tribocorrosion is of great practical importance, but it must be combined with the knowledge of methods of forecasting the value of wear. This paper presents a model of prediction of tribocorrosive wear adapted to corrodible materials – ADI containing Ni and Cu, with the strength class of 800 MPa – and results of a two-stage study on the tribocorrosive wear. Presented results indicate a distinct effect of synergy between friction and corrosion in the total wear of ADI. The tribocorrosion tests confimed the adequacy of the model developed for the ADI.

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Authors and Affiliations

A.N. Wieczorek
A. Stachowiak
W. Zwierzycki
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Abstract

In this study a group of selected transformation kinetics equations is applied to describe the isothermal ferritic transformation in austempered ductile iron (ADI). A series of dilatometric tests has been carried out on ADI at different temperatures. The obtained experimental data are utilized to determine the parameter values of the considered kinetic equations. It is found that the transformation kinetics models by Starink, Austin and Rickett are substantially more effective at describing the ferritic transformation in ADI than the much celebrated Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation. Furthermore, it is demonstrated that evaluating the kinetic parameters using the least squares method instead of calculating them from vastly used formulas can significantly improve the accuracy of the JMAK model’s predictions.

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Authors and Affiliations

C. Suchocki
D. Myszka
K. Wasiluk
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Abstract

Studies were carried out to determine the effect of heat treatment parameters on the plastic properties of unalloyed ausferritic ductile iron,

such as the elongation and toughness at ambient temperature and at – 60 °C. The effect of austenitizing temperature (850, 900 and 950°C)

and ausferritizing time (5 - 180 min.) at a temperature of 360°C was also discussed. The next step covered investigations of

a relationship that is believed to exist between the temperature (270, 300, 330, 360 and 390 °C) and time (5, 10, 30, 60, 90, 120, 150, 180,

240 min.) of the austempering treatment and the mechanical properties of unalloyed ausferritic ductile iron, when the austenitizing

temperature is 950°C. The “process window” was calculated for the ADI characterized by high toughness corresponding to the EN-GJS800-10-RT

and EN-GJS-900-8 grades according to EN-PN 1564 and to other high-strength grades included in this standard. Low-alloyed

cast iron with the nodular graphite is an excellent starting material for the technological design of all the ausferritic ductile iron grades

included in the PN-EN-1624 standard. The examined cast iron is characterized by high mechanical properties stable within the entire range

of heat treatment parameters.

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Authors and Affiliations

E. Guzik
M. Sokolnicki
A. Nowak
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Abstract

The study presented here is related with one of the components of a hybrid decision support system called CAPCAST (Computer Aided Process - CAST), developed under a research project at the Faculty of Metals Engineering and Industrial Computer Science, AGH University of Science and Technology. This is a module for rule generation to serve the knowledge base operating in an expert system. The scope of the system operation involves the selection of technological parameters for the manufacture of machine parts from ductile iron. However, it can be extended to include other materials and technologies.

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Authors and Affiliations

B. Mrzygłód
K. Ścira
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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.

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Authors and Affiliations

A. Krzyńska
A. Kochański
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Abstract

Ductile iron was quenched using two-variant isothermal transformation. The first treatment variant consisted of one-phase austenitization at a temperature tγ = 830, 860 or 900°C, cooling down to an isothermal transformation temperature of 300 or 400°C and holding from 8 to 64 minutes. The second treatment variant consisted of two-phase austenitization. Cast iron was austenitizied at a temperature tγ = 950°C and cooled down to a supercritical temperature tγ’ = 900, 860 or 830°C. Isothermal transformation was conducted under the same conditions as those applied to the first variant. Ferrite cast iron was quenched isothermally. Basic strength (Rp0.2, Rm) and plastic (A5) properties as well as matrix microstructure and hardness were examined. As a result of heat treatment, the following ADI grades were obtained: EN-GJS-800-8, EN-GJS-1200-2 and EN-GJS-1400-1 in accordance with PN–EN 1564:2000 having plasticity of 1.5÷4 times more than minimum requirements specified in the standard.

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Authors and Affiliations

T. Giętka
T. Szykowny
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Abstract

A mathematical model of austenite - bainite transformation in austempered ductile cast iron has been presented. The model is based on a model developed by Bhadeshia [1, 2] for modelling the bainitic transformation in high-silicon steels with inhibited carbide precipitation. A computer program has been developed that calculates the incubation time, the transformation time at a preset temperature, the TTT diagram and carbon content in unreacted austenite as a function of temperature. Additionally, the program has been provided with a module calculating the free energy of austenite and ferrite as well as the maximum driving force of transformation. Model validation was based on the experimental research and literature data. Experimental studies included the determination of austenite grain size, plotting the TTT diagram and analysis of the effect of heat treatment parameters on the microstructure of ductile iron. The obtained results show a relatively good compatibility between the theoretical calculations and experimental studies. Using the developed program it was possible to examine the effect of austenite grain size on the rate of transformation.

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Authors and Affiliations

I. Olejarczyk-Wożeńska
M. Głowacki
H. Adrian
B. Mrzygłód
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Abstract

This paper presents the results of the abrasive wear resistance of selected types of nodular cast iron, including ADI, cooperating with quartz sand and 100 grit abrasive paper. It has been shown that carbides in nodular cast iron cause an increase in wear resistance of 6 to 12% depending on the surface fraction of the carbides and type of the matrix. For the same unit pressure the mass loss of the cast iron cooperating with quartz sand is many times larger than the cast iron cooperating with abrasive paper. For both abrasives the highest wear resistance showed nodular cast iron with upper and lower bainite and carbides.
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Authors and Affiliations

G. Gumienny
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Abstract

The paper discusses possible applications of the percolation theory in analysis of the microstructure images of polycrystalline materials.

Until now, practical use of this theory in metallographic studies has been an almost unprecedented practice. Observation of structures so

intricate with the help of this tool is far from the current field of its application. Due to the complexity of the problem itself, modern

computer programmes related with the image processing and analysis have been used. To enable practical implementation of the task

previously established, an original software has been created. Based on cluster analysis, it is used for the determination of percolation

phenomena in the examined materials. For comparative testing, two two-phase materials composed of phases of the same type (ADI

matrix and duplex stainless steel) were chosen. Both materials have an austenitic - ferritic structure. The result of metallographic image

analysis using a proprietary PERKOLACJA.EXE computer programme was the determination of the content of individual phases within

the examined area and of the number of clusters formed by these phases. The outcome of the study is statistical information, which

explains and helps in better understanding of the planar images and real spatial arrangement of the examined material structure. The results

obtained are expected to assist future determination of the effect that the internal structure of two-phase materials may have on a

relationship between the spatial structure and mechanical properties.

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Authors and Affiliations

W. Trzaskowski
S. Świłło
W. Sobaszek
D. Myszka
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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.
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Authors and Affiliations

W. Trzaskowski
P. Nawrocki
K. Łukasik
D. Myszka
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Abstract

The objective of studies presented in this publication was structuring of research knowledge about the ADI functional properties and

changes in these properties due to material treatment. The results obtained were an outcome of research on the selection of a format of

knowledge representation that would be useful in further work aiming at the design, application and implementation of an effective system

supporting the decisions of a technologist concerning the choice of a suitable material (ADI in this case) and appropriate treatment process

(if necessary). ALSV(FD) logic allows easy modelling of knowledge, which should let addressees of the target system carry out

knowledge modelling by themselves. The expressiveness of ALSV (FD) logic allows recording the values of attributes from the scope of

the modelled domain regarding ADI, which is undoubtedly an advantage in the context of further use of the logic. Yet, although the logic

by itself does not allow creating the rules of knowledge, it may form a basis for the XTT format that is rule-based notation. The difficulty

in the use of XTT format for knowledge modelling is acceptable, but formalism is not suitable for the discovery of rules, and therefore the

knowledge of technologist is required to determine the impact of process parameters on values that are functional properties of ADI. The

characteristics of ALSV(FD) logic and XTT formalism, described in this article, cover the most important aspects of a broadly discussed,

full evaluation of the applicability of these solutions in the construction of a system supporting the decisions of a technologist.

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Authors and Affiliations

S. Kluska-Nawarecka
K. Regulski
G. Rojek
D. Wilk-Kołodziejczyk
W.T. Adrian

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