Nauki Techniczne

Archives of Foundry Engineering

Zawartość

Archives of Foundry Engineering | 2016 | No 2 |

Abstrakt

The paper presents data concerning the total production of castings over the 2000-2014 period, both on a global scale, and in Poland. The

basic types of casting alloys were taken into account. Changes in the production volume and structure over the period of the analysed 15

years were pointed out with respect to countries leading in foundry production. The topmost position in the world foundry industry is held

by China for several years (with almost 45% share in the foundry market), the second place is taken by India (with almost 9% share). A

distinct reduction in the shares of the once significant producers of castings, such as USA, Japan, Germany, Russia, Italy, or France, was

observed over the 2000-2014 period. Poland had a share of 1.16% in 2000, and of 1.02% in 2014. Comparing the detailed data concerning

the years 2000 and 2014, one can see that the fractions of castings made of ductile iron, cast steel, aluminium alloys, or magnesium alloys

increase on a global scale, while such alloys as grey cast iron or malleable are in decline.

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One way to ensure the required technical characteristics of castings is the strict control of production parameters affecting the quality of

the finished products. If the production process is improperly configured, the resulting defects in castings lead to huge losses. Therefore,

from the point of view of economics, it is advisable to use the methods of computational intelligence in the field of quality assurance and

adjustment of parameters of future production. At the same time, the development of knowledge in the field of metallurgy, aimed to raise

the technical level and efficiency of the manufacture of foundry products, should be followed by the development of information systems

to support production processes in order to improve their effectiveness and compliance with the increasingly more stringent requirements

of ergonomics, occupational safety, environmental protection and quality. This article is a presentation of artificial intelligence methods

used in practical applications related to quality assurance. The problem of control of the production process involves the use of tools such

as the induction of decision trees, fuzzy logic, rough set theory, artificial neural networks or case-based reasoning.

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The scope of this work focuses on the aspects of quality and safety assurance of the iron cast manufacturing processes. Special attention

was given to the processes of quality control and after-machining of iron casts manufactured on automatic foundry lines. Due to low level

of automation and huge work intensity at this stage of the process, a model area was established which underwent reorganization

in accordance with the assumptions of the World Class Manufacturing (WCM). An analysis of work intensity was carried out and the costs

were divided in order to identify operations with no value added, particularly at individual manufacturing departments. Also an analysis

of ergonomics at work stations was carried out to eliminate activities that are uncomfortable and dangerous to the workers' health. Several

solutions were proposed in terms of rationalization of work organization at iron cast after-machining work stations. The proposed solutions

were assessed with the use of multi-criteria assessment tools and then the best variant was selected based on the assumed optimization

criteria. The summary of the obtained results reflects benefits from implementation of the proposed solutions.

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The results of investigations of spent moulding sands taken from the mould in which the metal core cooling system - to increase the

cooling rate of the ladle casting - was applied, are presented in the hereby paper. The changes of the spent moulding sand at the casting

external side being the result of degradation and destruction processes of organic binder, were analysed in this publication. Since the

reclaimed material, obtained as a result of the mechanical reclamation of spent sands of the same type, is used as a grain matrix of the

moulding sand, the amount of a binder left from the previous technological cycle is essential for the sound castings production. On the

bases of investigations of the thermal analysis, ignition losses, dusts contents and pH values of the samples taken from the spent sand the

conditions under which the process of gases displacing in the casting mould was realised as well as factors limiting the efficient mould

degassing - were considered in this study. The possible reason of a periodical occurrence of an increased number of casting defects due to

changing gas volume emission, being the reason of the realised technological process, was indicated.

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In order to predict the distribution of shrinkage porosity in steel ingot efficiently and accurately, a criterion R√L and a method to obtain its

threshold value were proposed. The criterion R√L was derived based on the solidification characteristics of steel ingot and pressure

gradient in the mushy zone, in which the physical properties, the thermal parameters, the structure of the mushy zone and the secondary

dendrite arm spacing were all taken into consideration. The threshold value of the criterion R√L was obtained with combination of

numerical simulation of ingot solidification and total solidification shrinkage rate. Prediction of the shrinkage porosity in a 5.5 ton ingot of

2Cr13 steel with criterion R√L>0.21 m・℃1/2・s

-3/2 agreed well with the results of experimental sectioning. Based on this criterion,

optimization of the ingot was carried out by decreasing the height-to-diameter ratio and increasing the taper, which successfully eliminated

the centreline porosity and further proved the applicability of this criterion.

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The main work of this paper focuses on the simulation of binary alloy solidification using the phase field model and adaptive octree grids.

Ni-Cu binary alloy is used as an example in this paper to do research on the numerical simulation of isothermal solidification of binary

alloy. Firstly, the WBM model, numerical issues and adaptive octree grids have been explained. Secondary, the numerical simulation

results of three dimensional morphology of the equiaxed grain and concentration variations are given, taking the efficiency advantage of

the adaptive octree grids. The microsegregation of binary alloy has been analysed emphatically. Then, numerical simulation results of the

influence of thermo-physical parameters on the growth of the equiaxed grain are also given. At last, a simulation experiment of large scale

and long-time has been carried out. It is found that increases of initial temperature and initial concentration will make grain grow along

certain directions and adaptive octree grids can effectively be used in simulations of microstructure.

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Dispersion hardening, as the main heat treatment of silumins having additions of copper and magnesium, results in considerable increase

of tensile strength and hardness, with simultaneous decrease of ductility of the alloy. In the paper is presented an attempt of introduction of

heat treatment operation consisting in homogenizing treatment prior operation of the dispersion hardening, to minimize negative effects of

the T6 heat treatment on plastic properties of hypereutectoidal AlSi17CuNiMg alloy. Tests of the mechanical properties were performed

on a test pieces poured in standardized metal moulds. Parameters of different variants of the heat treatment, i.e. temperature and time of

soaking for individual operations were selected basing on the ATD (Thermal Derivation Analysis) diagram and analysis of literature. The

homogenizing treatment significantly improves ductility of the alloy, resulting in a threefold increase of the elongation and more than

fourfold increase of the impact strength in comparison with initial state of the alloy. Moreover, the hardness and the tensile strength (Rm)

of the alloy decrease considerably. On the other hand, combination of the homogenizing and dispersion hardening enables increase of

elongation with about 40%, and increase of the impact strength with about 25%, comparing with these values after the T6 treatment,

maintaining high hardness and slight increase of the tensile strength, comparing with the alloy after the dispersion hardening

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Recent research in the process of aluminum alloy die castings production, which is nowadays deeply implemented into the rapidly growing

automobile, shipping and aircraft industries, is aimed at increasing the useful qualitative properties of the die casting in order to obtain its

high mechanical properties at acceptable economic cost. Problem of technological factors of high pressure die casting has been a subject of

worldwide research (EU, US, Japan, etc.). The final performance properties of die castings are subjected to a large number of

technological factors. The main technological factors of high pressure die casting are as follows: plunger pressing speed, specific

(increase) pressure, mold temperature as well as alloy temperature. The contribution discusses the impact of the plunger pressing speed

and specific (increase) pressure on the mechanical properties of the casting aluminum alloy.

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The main aim of this study was to examine the compression-induced state of stress arising in castings of the guide grates during operation

in pusher-type furnaces for heat treatment. The effect of grate compression is caused by its forced movement in the furnace. The

introduction of flexible segments to the grate structure changes in a significant way the stress distribution, mainly by decreasing its value,

and consequently considerably extends the lifetime of the grates. The stress distribution was examined in the grates with flexible segments

arranged crosswise (normal to the direction of the grate compression) and lengthwise (following the direction of force). A regression

equation was derived to describe the relationship between the stress level in a row of ribs in the grate and the number of flexible segments

of a lengthwise orientation placed in this row. It was found that, regardless of the distribution of the flexible segments in a row, the stress

values were similar in all the ribs included in this row, and in a given row of the ribs/flexible segments a similar state of stress prevailed,

irrespective of the position of this row in the whole structure of the grate and of the number of the ribs/flexible segments introduced

therein. Parts of the grate responsible for the stress transfer were indicated and also parts which play the role of an element bonding the

structure.

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The paper presents results of an analysis of material density distribution in stampings press-moulded in metal dies from raw refractory

materials based on alumina-magnesia-carbon aggregate. The stampings, fabricated on LAEIS HPF 1250 pressing machine, are blanks from

which refractory precast shapes are manufactured by means of drying and firing. Samples for material density evaluation were cut out

from test stampings with the use of diamond-reinforced disc. Density of the material was determined in thirteen layers of stampings

denoted with letters A through M.

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The paper presents results of assessment of the unit pressure force within the refractory material volume in the course press-moulding of

stampings for refractory precast shapes. The force was evaluated with the use of physical simulation of deformation undergone by lead

balls placed in the raw refractory mass subjected to pressing in a metal die. To determine the value of unit pressure force applied to the

aggregate grains in the course of stamping press-moulding, physical model of deformation of a sphere induced by the uniaxial stress state

was used.

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High-chromium cast irons are used as abrasion resistant materials. Their wear resistance depends on quantity of carbides and the matrix

supporting these carbides. The paper presents the results of cast irons of chemical composition (in wt. %) 19–22 Cr and 2–4.5 C alloyed by

1.7 Mo + 5 Ni + 2 Mn to improve their toughness, which were tested in working conditions of ferroalloys crushing. Tests showed that

these as-cast chromium cast irons with mostly austenitic matrix achieved the hardness of 38-45 HRC, but their relative abrasion resistance

Ψ ranged from 1.3 to 4.6, was higher comparing to the tool made from the X210Cr12 steel heat treated on hardness 61 HRC. The

transformation of austenite into martensite occurs not only at the worn strained areas (on a surface of scratch) but also in their

neighbourhood. Due to the work hardening of relatively large volumes of transformed austenite the cast iron possesses high abrasion

resistance also on the surfaces where low pressures are acting. The tough abrasion-resistant cast iron well proved for production of

dynamic and wear stressed castings e.g., crusher hammers, cutting tools for ceramic etc.

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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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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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The spectroscopic FT-IR and FT-Raman methods allowed to identify the cross-linking process of the aqueous composition of poly(acrylic

acid)/sodium salt of carboxymethyl starch (PAA/CMS-Na) applied as a binder for moulding sands (as a novel group binders BioCo). The

cross-linking was performed by physical agent, applying the UV-radiation. The results of structural studies (IR, Raman) confirm the

overlapping of the process of cross-linking polymer composition PAA/CMS-Na in UV radiation. Taking into account the ingredients and

structure of the polymeric composition can also refer to a curing process in a binder - mineral matrix mixture. In the system of bindermineral

matrix under the influence of ultraviolet radiation is also observed effect of binding. However, the bonding process does not occur

in the entire volume of the investigated system, but only on the surface, which gives some possibilities for application in the use of UV

curing surface of cores, and also to cure sand moulds in 3D printing technology

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In order to increase wear resistance cast steel casting the TiC-Fe-Cr type composite zones were fabricated. These zones were obtained by

means of in situ synthesis of substrates of the reaction TiC with a moderator of a chemical composition of white cast iron with nickel of

the Ni-Hard type 4. The synthesis was carried out directly in the mould cavity. The moderator was applied to control the reactive

infiltration occurring during the TiC synthesis. The microstructure of composite zones was investigated by electron scanning microscopy,

using the backscattered electron mode. The structure of composite zones was verified by the X-ray diffraction method. The hardness of

composite zones, cast steel base alloy and the reference samples such as white chromium cast iron with 14 % Cr and 20 % Cr, manganese

cast steel 18 % Mn was measured by Vickers test. The wear resistance of the composite zone and the reference samples examined by ballon-disc

wear test. Dimensionally stable composite zones were obtained containing submicron sizes TiC particles uniformly distributed in

the matrix. The macro and microstructure of the composite zone ensured three times hardness increase in comparison to the cast steel base

alloy and one and a half times increase in comparison to the white chromium cast iron 20 % Cr. Finally ball-on-disc wear rate of the

composite zone was five times lower than chromium white cast iron containing 20 % Cr.

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NC11 steel, in view of the specificity of its manufacturing process, is characterised with band-like orientation of carbides. Depending

on the direction of cutting the material for the inserts out of commercially available steel products, carbide bands can be oriented

in parallel or perpendicularly to the direction in which aggregate grains move in the process of pressing stampings. It has been found that

in case of scratches made in direction perpendicular to carbide bands, depth of the scratches is less than this observed when scratches are

made in direction coinciding with prevailing orientation of carbide precipitates.

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One of the methods to prevent unsuitable lubrication of moving components of devices and machinery is using bi-metal and three-metal

bearings. Centrifugal casting process is one of the manufacturing methods that is used for such bearings. In this study, the purpose is

microstructure evaluation of the bonding location and length determination of diffusion bond in structural steel-bronze. A mold made of

structural steel with inner diameter of 240mm, length of 300mm and thickness of 10mm was coated by a 6mm film of bronze under

centrifugal casting process. At first, a bronze ingot with dimension of 5mm×10mm×20mm is located inside of the hollow cylindrical mold

and then the two ends of it will be sealed. During mold rotation with the rate of 800 rpm, two high power flames are used for heating the

mold under Ar gas atmosphere to melt the bronze ingot at 1000˚C. After 15minutes, the system is cooled rapidly. Results showed that the

diffusion bonding of bronze in structural steel to depth of 1.2µm from the bonding line was obtained. In this bonding, copper element was

diffused to 50% of its initial concentration.

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Metal pieces wear out due to variable loading, because cracks formed on their surface of them. In order to increase useful life of metal

pieces with the help of different methods of welding, surface cracks are repaired. In this research, performance of the diffusion welding of

pure iron powder through magnetic induction evaluated for repairing structural steel surface cracks. First, four specimens prepared

including one control specimen and other three specimens grooved specimens in length of 6.25mm and in depth of 1mm and groove

width in the sizes of 0.5, 0.75 and 1mm. Then by a coil, the induced current created in the piece surface. After crossing the current, the

powder melted and the groove repaired due to diffusion welding. To prevent oxidation, the atmosphere inside the coil filled with argon

gas. The results show that after repairing surface groove, tensile strength of the repaired specimens reached to the tensile strength of

control specimen with the margin of 7.5%.

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The material selected for this investigation was low alloy steel weld metal deposit (WMD) after MAG welding with micro-jet cooling. The

present investigation was aimed as the following tasks: analyze impact toughness of WMD in terms of micro-jet cooling parameters. Weld

metal deposit (WMD) was first time carried out for MAG welding with micro-jet cooling of compressed air and gas mixture of argon and

air. Until that moment only argon, helium and nitrogen and its gas mixture were tested for micro-jet cooling

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Magnesium alloy with 5 wt% Al, 0.35 wt% Mn and 5 wt% rare earth elements (RE) was prepared and gravity cast into a sand mould.

Microstructure investigations were conducted. Analyses of the Mg-Al-RE alloy microstructure were carried out by light microscopy,

scanning electron microscopy and the XRD technique. In the as-cast condition, the alloy was composed of α-Mg, Al11RE3 and

Al10RE2Mn7 intermetallic phases. Additionally, due to non-equilibrium solidification conditions, an Al2RE intermetallic phase was

revealed.

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The article contains basic information associated with the impact of the FSW process parameters on the forming of a weld while friction

welding of aluminium casting alloys. Research was conducted using specially made samples containing a rod of casting alloy mounted in

the wrought alloy in the selected area of FSW tool acting. Research has thrown light on the process of joining materials of significantly

dissimilar physical properties, such as casting alloys and wrought alloys. Metallographic testing of a weld area has revealed the big impact

of welding conditions, especially tool rotational speed, on the degree of metal stirring, grain refinement and shape factor of a weld. As the

result of research it has been stated that at the high tool rotational speed, the metals stirring in a weld is significantly greater than in case of

welding at low rotational speeds, however this fails to influence the strength of a weld. Plastic strain occurring while welding causes very

high refinement of particles in the tested area and changing of their shape towards particles being more equiaxial. In the properly selected

welding conditions it is possible to obtain joints of correct and repeatable structure, however in the case of the accumulation of cavities in

the casting alloy the FSW process not always eliminates them.

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Redakcja

CHIEF EDITORS
Editor
J. Szajnar
Deputy Editor
J. Jezierski

SUBJECT EDITORS
Theoretical Aspects of Casting Processes
K. Eigenfeld – Freiberg, Germany
E. Guzik – Kraków, Poland
T. G. Mathia - Lyon, France
W. Wołczyński – Kraków, Poland
Innovative Foundry Technologies and Materials
T. Elbel – Ostrava, Czech Republic
Z. Ignaszak – Poznań, Poland
O. P. Pandey – Punjab, India
A. Pereira - Vigo, Spain
Foundry Processes Computer Aiding
B. Mochnacki – Częstochowa, Poland
J. Roučka – Brno, Czech Republic
J.S. Suchy – Kraków, Poland
Mechanization, Automation and Robotics in Foundry
J. Bast – Freiberg, Germany
R. Wrona – Kraków, Poland
Transport Systems in Foundry
J. Dańko – Kraków, Poland
Z. Li – Shijiazhuang, China
Castings Quality Management
D. Bolibruchova– Żilina, Slovak Republic
J. D. B. de Mello - Santa Monica, Brazil
M. Perzyk – Warszawa, Poland
Environment Protection
M. Holtzer – Kraków, Poland
H. Polzin – Freiberg, Germany
J. Sobczak – Kraków, Poland
I. Volchok – Zaporizhzhya, Ukraine

EDITORIAL ADVISORY BOARD
J. Braszczyński – Częstochowa, Poland
B. K. Dhindaw – Rupnagar, India
L. A. Dobrzański – Gliwice, Poland
W. A. Hufenbach – Dresden, Germany
P. Jelínek – Ostrava, Czech Republic
L. Jeziorski – Częstochowa, Poland
J. Lacaze – Toulouse, France
V. L. Naydek – Kiev, Ukraine
A. Passerone – Genova, Italy
I. Riposan – Bucharest, Romania
F. Romankiewicz – Zielona Góra, Poland
A. Sládek – Żilina, Slovak Republic

INTERNATIONAL SCIENTIFIC REVIEW COMMITTEE
S. A. Argyropoulos – Toronto, Canada
M. Azadi – Tehran, Iran
Y. Babaskin – Kiev, Ukraine
K. Bako – Miskolc, Hungary
E. Bayraktar – Paris, France
L. Bechný – Zilina, Slovak Republic
V. Bednarova - Ostrava, Czech Republic
F. Bińczyk – Katowice, Poland
A. Bokota – Częstochowa, Poland
G.P. Borisov – Kiev, Ukraine
A. Bydałek – Kraków, Poland
C. H. Cáceres – Brisbane, Australia
J. Čech – Brno, Czech Republic
L. Q. Chen – Shenyang, China
A. Chojecki – Kraków, Poland
M. Cholewa – Gliwice, Poland
I. A. Dibrov – Moscow, Russia
D. Dispinar – Istanbul, Turkey
S. M. Dobosz – Kraków, Poland
V. I. Dubodelov – Kiev, Ukraine
A. Fedoryszyn – Krakow, Poland
J. Głownia – Kraków, Poland
K. Granat – Wrocław, Poland
J. Hampl – Ostrava, Czech Republic
J. Helber – Düsseldorf, Germany
M. Hetmańczyk – Katowice, Poland
M. Horáček – Brno, Czech Republic
M. Kaczorowski – Warszawa, Poland
W. Kapturkiewicz – Kraków, Poland
R. Kawalla – Freiberg, Germany
Z. Konopka – Czestochowa, Poland
D. Kopyciński – Kraków, Poland
W. K. Krajewski – Kraków, Poland
Z. Libo – Beijing, China
P. Lichy – Ostrava, Czech Republic
Y. P. Lim – Setapak, Malaysia
T. Lipiński – Olsztyn, Poland
E. Majchrzak – Gliwice, Poland
A. Mityayev - Zaporizhzhya, Ukraine
M. Murgaš – Trnava, Slovak Republic
I. Nová – Liberec, Czech Republic
W. Orłowicz – Rzeszów, Poland
T. Pacyniak – Łódź, Poland
B. Piekarski – Szczecin, Poland
A. Rimmer – West Bromwich, United Kingdom
S. Samavedam – Hyderabad, India
P. Schumacher – Leoben, Austria
N. Sczygiol – Częstochowa, Poland
P. Skočovský – Żilina, Slovak Republic
M.S. Soiński – Częstochowa, Poland
J. Sokolowski – Ottawa, Kanada
K. V. Sudhakar – Butte, USA
B. G. Thomas - Champaign, USA
M. Trbižan – Ljubljana, Slovenia
J. Vuorinen – Tampere, Finland
E. Ziółkowski – Kraków, Poland
J. Zych – Kraków, Poland

ASSOCIATE EDITORS
D. Bartocha – Gliwice, Poland, - editorial secretary
J. Suchoń – Gliwice, Poland - editorial secretary
J. Szymszal – Katowice, Poland, Statistic Editor
A. Dulska – Gliwice, Poland
M. Kondracki – Gliwice, Poland
C. Borek –Chicago, USA, Language Editor

 

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