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Number of results: 31
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Abstract

The paper presents a detailed description of the process of creation of a surface alloy layer (using high-carbon ferrochromium) on the cast steel casting. The mechanism of the surface alloy layer is based on the known theories [5,6]. The proposed course of formation of the layers has been extended to decarburization stage of steel. The research included proving the presence of carbon-lean zone. The experiment included the analysis of the distribution of elements and microhardness measurement.

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Authors and Affiliations

A. Walasek
J. Szajnar
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Abstract

Results of investigations of wear resistant of two species of cast steel were introduced in the article (low-alloyed and chromium cast steel) on the background of the standard material which was low alloy wear resistant steel about the trade name CREUSABRO ®8000. The investigations were executed with two methods: abrasive wears in the stream of loose particles (the stream of quartz sand) and abrasive wears particles fixed (abrasive paper with the silicon carbide). Comparing the results of investigations in the experiments was based about the counted wear index which characterizes the wears of the studied material in the relation to the standard material.

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Authors and Affiliations

A. Studnicki
J. Szajnar
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Abstract

The paper presents the results of simulation of alloy layer formation process on the model casting. The first aim of this study was to

determine the influence of the location of the heat center on alloy layer’s thickness with the use of computer simulation. The second aim of

this study was to predict the thickness of the layer. For changes of technological parameters, the distribution of temperature in the model

casting and temperature changes in the characteristic points of the casting were found for established changes of technological

parameters. Numerical calculations were performed using programs NovaFlow&Solid. The process of obtaining the alloy layer with good

quality and proper thickness depends on: pouring temperature, time of premould hold at the temperature above 1300o

C. The obtained

results of simulation were loaded to authorial program Preforma 1.1 in order to determine the predicted thickness of the alloy casting

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Authors and Affiliations

J. Szajnar
C. Baron
A. Walasek
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Abstract

In the paper the results and analysis of corrosion tests were presented for low-alloyed cast steel in as-cast state and after heat treatment

operations. Such alloys are applied for heavy loaded parts manufacturing, especially for mining industry. The corrosion test were

performed in conditions of high salinity, similar to those occurring during the coal mining. The results have shown, that small changes in

chemical composition and the heat treatment influence significantly the corrosion behaviour of studied low-alloyed cast steels.

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Authors and Affiliations

A. Studnicki
M. Kondracki
J. Szajnar
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Abstract

The article presents the technology of layered casting with the use of 3D printing to make a frame insert. The insert was made of powdered titanium and then filled with liquid cast iron. The paper presents the results of research, including structure observation and hardness measurements, as well as abrasion resistance tests. The results indicate the possibility of creating a local reinforcement using a frame insert. The resulting casting is characterized by a local increase in hardness and, in addition, an increase in abrasion resistance of the entire surface layer. The quality of the obtained connection depends strongly on the casting parameters.

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Authors and Affiliations

A. Dulska
ORCID: ORCID
J. Szajnar
ORCID: ORCID
M. Król
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Abstract

The paper presents selected granular ceramic materials available on the Polish market. Their characteristics have been determined in the aspect on application in the production of iron alloy-ceramic composite. The possibility of obtaining a composite layer by means of bulk grains in molds of plates were considered, which was the foundation for experimental molds to be used in service tests. On the basis of obtaining results was stated that the knowledge of the characteristics of bulk grains enables the calculation of their quantity necessary for the composite production. When using the bulk grains the thickness of the composite layer is restricted by the thermal relations (cooler) and the physical phenomena (buoyancy, metal static pressure). Increasing amount of grains above definite condition causes surface defects in the castings. Each casting, due to its weight, shape and place of composite layer production requires an individual approach, both at the stage of formation and that of calculation of the required quantity of ceramic grains.
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Authors and Affiliations

A. Dulska
J. Kilarski
A. Studnicki
J. Szajnar
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Abstract

The paper presents a method of producing a grey cast iron casting locally reinforced with a titanium insert printed using SLM method (Selective Laser Melting). This article attempts to examine the impact of the selected geometry of titanium spatial insert on the surface layer formation on grey cast iron. The scope of the research focuses on metallographic examination - observation and analysis of the structure of the reinforced surface layer on a light and scanning microscope and a hardness measurement of the titanium layer area. Based on the obtained results, it was concluded that the reaction between titanium insert and metal (grey cast iron) locally develops numerous carbides precipitation (mainly TiC particles), which increases the hardness of the reinforced surface layer and local strengthening of the material. The ratio between the thickness of the support part (grey cast iron) and the working part (titanium insert) affects the resulting layers connection structure. The properties of the obtained reinforced surface layer depend mainly on the geometry of the insert (primarily on the internal dimensions of the connector) and the volume of the casting affecting the re-melting of the insert. A more concentrated structure of carbides precipitation occurs in castings with a full connector insert.

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Authors and Affiliations

A. Dziwoki
A. Dulska
J. Szajnar
M. Król
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Abstract

The results of research on stereological parameters of carbides in modified hypoeutectic chromium cast iron were shown in the paper. The

effect of distance the casting heat centre of casting to the carbide phase morphology was examined. The samples for metallographic

examination were taken from various locations of the model casting prepared in a special tester. This model casting was designed to

simulate the solidification of heavy castings. Using the proposed methodology the relation of the distance from the model mould and the

size, perimeter, length, width and the shape factor of carbides was examined. During the analysis, the values of stereological parameters of

carbides changed on various sections of the model casting.

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Authors and Affiliations

M. Gromczyk
A. Studnicki
M. Kondracki
J. Szajnar
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Abstract

This paper presents matters related to production of ceramic and cast iron composite. The composite was made with the use of a foam structured ceramic insert. The tests included measuring of hardness, impact strength and resistance to abrasive wear of the composite produced. On the basis of obtaining results was stated that the use of foamed ceramic filters provides good conditions of filling a ceramic framework with molten grey or chromium cast iron. The growth of hardness of the ceramic- grey cast iron composite is ca. 60% as compared to the grey cast iron hardness. The growth of hardness of the ceramic- chromium cast iron composite is slight and does not exceed 5 % in comparison to the chromium cast iron. Introduction of the ceramic inserts deteriorates the cast iron impact strength by ca. 20 - 30 %. The use of ceramic inserts increases the resistance to abrasive wear in case of grey cast iron by ca. 13% and in case of the chromium cast iron by ca. 10 %.
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Authors and Affiliations

A. Dulska
A. Studnicki
M. Cholewa
J. Szajnar
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Abstract

In this paper crystallization studies of low-alloyed construction cast steel were presented for different additions of chromium, nickel and

molybdenum modified with vanadium and titanium. Studies were conducted using developed TDA stand, which additionally enabled

evaluation of cooling rate influence on crystallization process of investigated alloys.

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Authors and Affiliations

A. Studnicki
M. Kondracki
J. Szajnar
T. Wróbel
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Abstract

The paper presents an innovative method of creating the layered castings. The innovation relies on application the 3D printing insert obtaining in SLM (selective laser melting) method. This type of scaffold insert made from pure Ti powder, was placed into mould cavity directly before pouring by grey cast iron. In result of used method was obtained grey cast iron casting with surface layer reinforced by titanium carbides. In range of studies were carried out metallographic researches using light microscope and scanning electron microscope, microhardness measurements and abrasive wear resistance. On the basis of obtaining results was stated that there is a possibility of reinforcing surface layer of the grey cast iron casting by using 3D printing scaffold insert in the method of mould cavity preparation. Moreover there was a local increase in hardness and abrasive wear resistance in spite of the precipitation of titanium carbides in surface layer of grey cast iron. While the usable properties of composite surface layer obtained in result of use of the method presented in the paper, strongly depend of dimensions of scaffold insert, mainly parameters Re and Ri.

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Authors and Affiliations

A. Dulska
J. Szajnar
N. Przyszlak
T. Wróbel
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Abstract

The paper presents the research results of horizontal continuous casting of ingots of aluminium alloy containing 2% wt. silicon (AlSi2).

Together with the casting velocity (velocity of ingot movement) we considered the influence of electromagnetic stirring in the area of the

continuous casting mould on refinement of the ingot’s primary structure and their selected mechanical properties, i.e. tensile strength, yield

strength, hardness and elongation. The effect of primary structure refinement and mechanical properties obtained by electromagnetic

stirring was compared with refinement obtained by using traditional inoculation, which consists in introducing additives, i.e. Ti, B and Sr,

to the metal bath. On the basis of the obtained results we confirmed that inoculation done by electromagnetic stirring in the range of the

continuous casting mould guarantees improved mechanical properties and also decreases the negative influence of casting velocity, thus

increasing the structure of AlSi2 continuous ingots.

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Authors and Affiliations

J. Szajnar
M. Stawarz
D. Bartocha
T. Wróbel
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Abstract

The paper presents the issue of synthetic cast iron production in the electric induction furnace exclusively on the steel scrap base. Silicon

carbide and synthetic graphite were used as carburizers. The carburizers were introduced with solid charge or added on the liquid metal

surface. The chemical analysis of the produced cast iron, the carburization efficiency and microstructure features were presented in the

paper. It was stated that ferrosilicon can be replaced by silicon carbide during the synthetic cast iron melting process. However, due to its

chemical composition (30% C and 70% Si) which causes significant silicon content in iron increase, the carbon deficit can be partly

compensated by the carburizer introduction. Moreover it was shown that the best carbon and silicon assimilation rate is obtained where the

silicon carbide is being introduced together with solid charge. When it is thrown onto liquid alloy surface the efficiency of the process is

almost two times less and the melting process lasts dozen minutes long. The microstructure of the cast iron produced with the silicon

carbide shows more bulky graphite flakes than inside the microstructure of cast iron produced on the pig iron base.

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Authors and Affiliations

J. Szajnar
A. Stojczew
J. Jezierski
M. Pawlyta
K. Janerka
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Abstract

In paper is presented results of studies concerning ingot of Al with a purity of 99.5% cast with use of stand of horizontal continuous

casting. Mainly together with casting velocity was considered influence of electromagnetic stirrer, which was placed in continuous casting

mould on refinement of ingots structure and theirs usability to plastic deformation. Effect of structure refinement and usability to plastic

deformation obtained by influence of electromagnetic stirring was compared with refinement obtained by use of traditional inoculation,

which consists in introducing of additives i.e. Ti and B to metal bath. On the basis of obtained results was affirmed that inoculation

realized by electromagnetic stirring in range of continuous casting mould guarantees improvement in structure refinement and usability to

rolling of pure Al continuous ingots.

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Authors and Affiliations

J. Szajnar
D. Bartocha
T. Wróbel
M. Stawarz
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Abstract

Some eutectic stripes have been generated in a hexagonal (Zn) - single crystal. The stripes are situated periodically with the constant interstripes

spacing. The eutectic structure in the stripes consists of strengthening inter-metallic compound, Zn16Ti, and (Zn) – solid solution.

The rod-like irregular eutectic structure (with branches) appears at low growth rates. The regular lamellar eutectic structure is observed at

middle growth rates. The regular rod-like eutectic structure exists exclusively in the stripes at some elevated growth rates. A new

thermodynamic criterion is recommended. It suggests that this eutectic regular structure is the winner in a morphological competition for

which the minimum entropy production is lower. A competition between the regular rod-like and the regular lamellar eutectic growth is

described by means of the proposed criterion. The formation of branches within irregular eutectic structure is referred to the state of

marginal stability. A continuous transitions from the marginal stability to the stationary state are confirmed by the continuous

transformations of the irregular eutectic structure into the regular one.

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Authors and Affiliations

J. Szajnar
W. Wołczyński
S. Kjelstrup
D. Bedeaux
B. Billia

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