Nauki Techniczne

Archives of Foundry Engineering

Zawartość

Archives of Foundry Engineering | 2017 | vol. 17 | No 1 |

Abstrakt

Casting covers major area of production all over the world. Resin bonded casting is widely used in today’s manufacturing industries. Furan

No bake casting is most widely accepted in indian foundries due to its excellent surface finish and dimensional stability. It is a self-setting

binder and it has a lower work and strip times. Though the casting process is also known as process of uncertainty, in the present study, an

attempt has been made to investigate the effect of Grain Fineness Number, Loss of Ignition, Potential of Hydrogen, % of Resin with

respect to sand, Sand Temperature and Compressive strength of the mould on Sand Inclusion defect – one of the most dominating defect in

the Krislur Castomech Pvt. Ltd. Industry situated at Bhavnagar, Gujarat, India. The experiments were conducted based on response surface

methodology (RSM) and sequential approach using face centered central composite design. The results show that quadratic model with

removal of some insignificant term is comparatively best fits for Sand Inclusion Defect.

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Paper presents the results of ATD and DSC analysis of two superalloys used in casting of aircraft engine parts. The main aim of the

research was to obtain the solidification parameters, especially Tsol and Tliq, knowledge of which is important for proper selection of

casting and heat treatment parameters. Assessment of the metallurgical quality (presence of impurities) of the feed ingots is also a very

important step in production of castings. It was found that some of the feed ingots delivered by the superalloy producers are contaminated

by oxides located in shrinkage defects. The ATD analysis allows for quite precise interpretation of first stages of solidification at which

solid phases with low values of latent heat of solidification are formed from the liquid. Using DSC analysis it is possible to measure

precisely the heat values accompanying the phase changes during cooling and heating which, with knowledge of phase composition,

permits to calculate the enthalpy of formation of specific phases like γ or γ′.

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This paper deals with computer modelling of the retention of a synthetic diamond particle in a metallic matrix produced by powder

metallurgy. The analyzed sintered powders can be used as matrices for diamond impregnated tools. First, the behaviour of sintered cobalt

powder was analyzed. The model of a diamond particle embedded in a metallic matrix was created using Abaqus software. The

preliminary analysis was performed to determine the mechanical parameters that are independent of the shape of the crystal. The

calculation results were compared with the experimental data. Next, sintered specimens obtained from two commercially available powder

mixtures were studied. The aim of the investigations was to determine the influence of the mechanical and thermal parameters of the

matrix materials on their retentive properties. The analysis indicated the mechanical parameters that are responsible for the retention of

diamond particles in a matrix. These mechanical variables have been: the elastic energy of particle, the elastic energy of matrix and the

radius of plastic zone around particle.

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The cumulative results of investigations of the possibility of using the reclaimed materials after the mechanical, thermal or

mechanical-thermal reclamation for making cores by means of the blowing method in the alkaline CO2 technology, are

presented in the paper. Three kinds of spent sands: with furfuryl resin, bentonite and alkaline phenolic resin, obtained from

the foundry, were subjected to three kinds of reclamation: mechanical, thermal and combined mechanical-thermal, applying

for this aim adequate experimental devices. The obtained reclaims were assessed with regard to the degree of the matrix

liberation from the determined binding material. Reclaims of moulding sands with binders of the form of resin were assessed

with regard to ignition loss values and pH reaction, while reclaims of moulding sands with bentonite with regard to the

residual clay content and pH value. In all cases the results of the performed sieve analyses were estimated and the average

characteristic diameter dl was determined. The reclaimed matrix was applied as a full substitute of the fresh high-silica sand in typical

procedures of preparing core sands used for making shaped samples for bending strength investigations, Rg

u

.

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The results of investigations of the influence of the matrix grain sizes on properties of cores made by the blowing method are presented in

the hereby paper. Five kinds of matrices, differing in grain size compositions, determined by the laser diffraction method in the Analysette

22NanoTec device, were applied in investigations. Individual kinds of matrices were used for making core sands in the Cordis technology.

From these sands the shaped elements, for determining the apparent density of compacted sands and their bending strength, were made by

the blowing method. The shaped elements (cores) were made at shooting pressures being 3, 4 and 5 atn. The bending strength of samples

were determined directly after their preparation and after the storing time of 1 hour.

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This paper focuses on mechanical properties of self hardening moulding sands with furfuryl and alkyd binders. Elasticity as a new

parameter of moulding sands is investigated. With the use of presented testing equipment, it is possible to determine force kinetics and

deformation of moulding sand in real time. The need for this kind of study comes from the modern casting industry. New foundries can be

characterized with high intensity of production which is correlated with high level of mechanization and automatization of foundry

processes. The increasingly common use of manipulators in production of moulds and cores can lead to generation of new types of flaws,

caused by breakage in moulds and cores which could occur during mould assembly. Hence it is required that moulds and cores have high

resistance to those kinds of factors, attributing it with the phenomenon of elasticity. The article describes the theoretical basis of this

property, presents methods of measuring and continues earlier research.

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The aim of presented studies was to develop a new geometry of the overflow part of standard ATD–C tester for derivative thermal analysis

in a way that it would allow to obtain samples for abrasion and mechanical properties tests in the same mould without the need of cutting

them from a block of material. The pattern of new ATD–P tester has parts reflecting implemented samples. Computer simulations

regarding initial verification of new tester were performed in NovaFlow software. Chromium cast iron melts were made for testing the

sampler in real conditions and TDA analysis for casting material were conducted. The sandmix was prepared on silica sand matrix per the

ALPHASET technology. This new solution greatly simplifies the preparations of materials difficult to machine.

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A novel approach for treating the uncertainty about the real levels of finished products during production planning and scheduling process

is presented in the paper. Interval arithmetic is used to describe uncertainty concerning the production that was planned to cover potential

defective products, but meets customer’s quality requirement and can be delivered as fully valuable products. Interval lot sizing and

scheduling model to solve this problem is proposed, then a dedicated version of genetic algorithm that is able to deal with interval

arithmetic is used to solve the test problems taken from a real-world example described in the literature. The achieved results are compared

with a standard approach in which no uncertainty about real production of valuable castings is considered. It has been shown that interval

arithmetic can be a valuable method for modeling uncertainty, and proposed approach can provide more accurate information to the

planners allowing them to take more tailored decisions.

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The article presents chosen aspects of foundry engineering of the settlement dwellers, including the archaeometric characteristics and

metal science analysis of the artefacts, as well as an attempted reconstruction of the production organization. Discovered in Szczepidło

(Greater Poland), the foundry workshop is unique in Central European Bronze Age.

This workshop foundry operated roughly XIV-XII Century BC. Its production is evidenced by the presence of markers of the whole

production cycle: semi-finished and finished products, production waste, fragments of crucibles and casting ladles with traces of usage,

and tools. On this basis, the alloys and foundry technologies used have been described.

The analysis of foundry technology of copper alloys in the settlement area was carried out by observing the surface and structure of the

products, semi-finished artefacts and fragments of crucibles by applying optical microscopy (OM), confocal microscopy (CLSM) and Xray

radiography (RT). The investigations of compositions were made by means of the energy dispersive X-ray fluorescence spectroscopy

(ED-XRF) and scanning electron microscopy (SEM) coupled with an energy dispersive X-ray analysis system (EDS).

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The paper presents the results of the research on the effect of copper on the crystallization process, microstructure and selected properties

of the compacted graphite iron. Compacted graphite in cast iron was obtained using Inmold process. The study involved the cast iron

containing copper at a concentration up to approximately 4%. The effect of copper on the temperature of the eutectic crystallization as well

as the temperature of start and finish of the austenite transformation was given. It has been shown that copper increases the maximum

temperature of the eutectic transformation approximately by 5C per 1% Cu, and the temperature of the this transformation finish

approximately by 8C per 1% Cu. This element decreases the temperature of the austenite transformation start approximately by 5C per

1% Cu, and the finish of this transformation approximately by 6C per 1% Cu. It was found that in the microstructure of the compacted

graphite iron containing about 3.8% Cu, there are still ferrite precipitations near the compacted graphite. The effect of copper on the

hardness of cast iron and the pearlite microhardness was given. This stems from the high propensity to direct ferritization of this type of

cast iron. It has been shown copper increases the hardness of compacted graphite iron both due to its pearlite forming action as well as

because of the increase in the pearlite microhardness (up to approx. 3% Cu). The conducted studies have shown copper increases the

hardness of the compacted graphite iron approximately by 35 HB per 1% Cu.

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The paper presents the results of experimental-simulation tests of expansion-shrinkage phenomena occurring in cast iron castings. The

tests were based on the standard test for inspecting the tendency of steel-carbon alloys to create compacted discontinuities of the pipe

shrinkage type. The cast alloy was a high-silicone ductile iron of GJS - 600 - 10 grade. The validation regarding correctness of prognoses

of the shrinkage defects was applied mostly to the simulation code (system) NovaFlow & Solid CV (NFS CV). The obtained results were

referred to the results obtained using the Procast system (macro- and micromodel). The analysis of sensitivity of the modules responsible

for predicting the shrinkage discontinuities on selected pre-processing parameters was performed, focusing mostly on critical fractions

concerning the feeding flows (mass and capillary) and variation of initial temperature of the alloy in the mould and heat transfer

coefficient (HTC) on the casting - chill interface.

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The paper is focused on properties testing of materials used in form of iso-exo sleeves for risers in ferrous alloys foundry. They are grainyfibrous

materials, containing components which initiate and upkeep exothermic reaction. Thermo-physical parameters characterizing such

sleeves are necessary also to fill in reliable databases for computer simulation of processes in the casting-mould layout. Studies with use of

a liquid alloy, especially regarding different sleeves bring valuable results, but are also relatively expensive and require longer test

preparation time. A simplified method of study in laboratory conditions was proposed, in a furnace heated to a temperature above ignition

temperature of sleeve material (initiation of exothermic reaction). This method allows to determine the basic parameters of each new

sleeve supplied to foundries and assures relatively quick evaluation of sleeve quality, by comparison with previous sleeve supplies or with

sleeves brought by new providers.

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Measurements of the hardening process of the selected self-setting sands are presented in the hereby paper. Moulding sands were prepared

on the matrix of „Szczakowa” sand of the Sibelco Company. Two resins: phenol-formaldehyde-furfuryl (FF/AF) and urea-formaldehydefurfuryl

(MF/AF) were used for making moulding sands. – Methylbenzene-sulphonic acid was applied as a hardener for the moulding sand

on FF/AF resin, while paratoluene-sulphonic acid for the moulding sand on MF/AF resin. Both hardeners were used in two concentrations:

low – the so-called ‘slow’ hardener and high - ‘fast’ hardener. During investigations, the courses of the hardening process were

determined, more accurately changes of the velocity of the ultrasound wave passage through the moulding sand cL = f(t) and changes of

the moulding sand hardening degree versus time, Sx = f(t). In addition, the kinetics of the hardening process was determined.

Measurements were performed on the research stand for ultrasound investigations.

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Emission of gases under high temperature after pouring molten metal into moulds, which contain the organic binder or other additives

(solvents or curing agent), may be an important factor influencing both on the quality of the produced castings, and on the state of

environment. Therefore, a comprehensive study of the emitted gases would allow to determine restrictions on the use of the moulding

sands in foundry technologies, eg. the probability of occurrence of casting defects, and identify the gaseous pollutants emitted to the

environment. The aim of the research presented in this paper was to determine the amount of gases that are released at high temperatures

from moulding sands bonded by biopolymer binder and the quantitative assessment of the emitted pollutants with particular emphasis on

chemical compounds: benzene, toluene, ethylbenzene and xylenes (BTEX). The water-soluble modified potato starch as a sodium

carboxymethyl starch with low (CMS-NaL) or high (CMS-NaH) degree of substitution was a binder in the tested moulding sands.

A tests of gases emission level were conducted per the procedure developed at the Faculty of Foundry Engineering (AGH University of

Science and Technology) involving gas chromatography method (GC). The obtained results of the determination of amount of BTEX

compounds generated during the decomposition process of starch binders showed lower emission of aromatic hydrocarbons in comparison

with binder based on resin Kaltharz U404 with the acidic curing agent commonly used in the foundries.

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This article presents data on the anthropogenic air emissions of selected substances (CO2, SO2, total suspended particles (TSP), dioxins

and furans (PCDD/F), Pb and Cd) subject to reporting under the Climate Convention (UNFCCC) or the Convention on Long-range

Transboundary Air Pollution (UNECE CLRTAP). It also presents the national emissions of these substances in 2014 by the major source

categories and defines the share of metal production in these emissions. Analysis is based on national emission inventory reports. Most

important source of air emission in case of CO2 and SO2 is 1.A.1 Energy industries category. TSP and PCDD/F are emitted mainly from

fuel combustion in small sources (i.a. households). Emission of heavy metals (Pb and Cd) is connected mostly with 1.A.2. Manufacturing

industries and construction category. Metallurgy is significant source of emission only for lead and cadmium from among all considered

substances. The shares of particular sectors in the national emissions of given pollutants are important, in view of the possible reduction

measures and the determination in which industries they could bring about tangible results.

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The results of researches of sorption processes of surface layers of components of sand moulds covered by protective coatings are

presented in the hereby paper. Investigations comprised various types of sand grains of moulding sands with furan resin: silica sand,

reclaimed sand and calcined in temperature of 700oC silica sand. Two kinds of alcoholic protective coatings were used – zirconium and

zirconium – graphite. Tests were performed under condition of a constant temperature within the range 30 – 35oC and high relative air

humidity 75 - 80%. To analyze the role of sand grains in sorption processes quantitavie moisture sorption with use of gravimetric method

and ultrasonic method were used in measurements. The tendency to moisture sorption of surface layers of sand moulds according to the

different kinds of sand grains was specified. The effectiveness of protective action of coatings from moisture sorption was analyzed as

well.

Knowledge of the role of sand grains from the viewpoint of capacity for moisture sorption is important due to the surface casting defects

occurrence. In particular, that are defects of a gaseous origin caused by too high moisture content of moulds, especially in surface layers.

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The nanocomposites based on water glass matrix were attempted in the study. Nanoparticles of ZnO, Al2O3 or MgO in organic solutions

were applied into water glass matrix in the amounts of: 1.5; 3; 4 or 5 mas. %. Wettability of the quartz sad by the nanocomposites based on

water glass matrix was determined by testing changes of the wetting angle θ in time τ for the system: quartz – binder in non-stationary

state, by means of the device for measuring wetting angles. Wettability measurements were carried out under isothermal conditions at an

ambient temperature (20 – 25 oC). The modification improves wettability of quartz matrix by water glass, which is effective in improving

strength properties of hardened moulding sands. Out of the considered modifiers in colloidal solution of propyl alcohol water glass

modified by MgO nanoparticles indicated the smallest values of the equilibrium wetting angle θr. This value was equal app. 11 degrees and

was smaller no less than 40 degrees than θr value determined for not modified water glass. Viscosity η of nanocomposites based on water

glass matrix was determined from the flow curve, it means from the empirically determined dependence of the shearing stress τ on shear

rate γ: τ = f (γ) (1), by means of the rotational rheometer. Measurements were carried out at a constant temperature of 20 oC. The

modification influences the binder viscosity. This influence is conditioned by: amount of the introduced modifier as well as dimensions and

kinds of nanoparticles and organic solvents. The viscosity increase of the modified binder does not negatively influence its functional

properties.

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The work presents the results of examinations concerning the influence of various amounts of home scrap additions on the porosity of

castings made of MgAl9Zn1 alloy. The fraction of home scrap in the metal charge ranged from 0 to 100%. Castings were pressure cast by

means of the hot-chamber pressure die casting machine under the industrial conditions in one of the domestic foundries. Additionally, for

the purpose of comparison, the porosity of specimens cut out directly of the MgAl9Zn1 ingot alloy was also determined. The examinations

consisted in the qualitative assessment of porosity by means of the optical microscopy and its quantitative determination by the method of

weighting specimens in air and in water. It was found during the examination that the porosity of castings decreases with an increase in the

home scrap fraction in the metal charge. The qualitative examinations confirmed the beneficial influence of the increased home scrap

fraction on the porosity of castings. It was concluded that the reusing of home scrap in a foundry can be a good way of reduction of costs

related to the production of pressure castings.

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The paper presents results of bend tests at elevated temperatures of aluminium alloy EN AC-44200 (AlSi12) based composite materials

reinforced with aluminium oxide particles. The examined materials were manufactured by squeeze casting. Preforms made of Al2O3

particles, with volumetric fraction 10, 20, 30 and 40 vol.% of particles joined with sodium silicate bridges were used as reinforcement. The

preforms were characterised by open porosity ensuring proper infiltration with the EN AC-44200 (AlSi12) liquid alloy. The largest

bending strength was found for the materials containing 40 vol.% of reinforcing ceramic particles, tested at ambient temperature. At

increased test temperature, bending strength Rg of composites decreased in average by 30 to 50 MPa per 100°C of temperature increase.

Temperature increase did not significantly affect cracking of the materials. Cracks propagated mainly along the interfaces particle/matrix,

with no effect of the particles falling-out from fracture surfaces. Direction of cracking can be affected by a small number of

agglomerations of particles or of non-reacted binder. In the composites, the particles strongly restrict plastic deformation of the alloy,

which leads to creation of brittle fractures. At elevated temperatures, however mainly at 200 and 300°C, larger numbers of broken,

fragmented particles was observed in the vicinity of cracks. Fragmentation of particles occurred mainly at tensioned side of the bended

specimens, in the materials with smaller fraction of Al2O3 reinforcement, i.e. 10 and 20 vol.%.

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An innovative method for determining the structural zones in the large static steel ingots has been described. It is based on the

mathematical interpretation of some functions obtained due to simulation of temperature field and thermal gradient field for solidifying

massive ingot. The method is associated with the extrema of an analyzed function and with its points of inflection. Particularly, the CET

transformation is predicted as a time-consuming transition from the columnar- into equiaxed structure. The equations dealing with heat

transfer balance for the continuous casting are presented and used for the simulation of temperature field in the solidifying virtual static

brass ingot. The developed method for the prediction of structural zones formation is applied to determine these zones in the solidifying

brass static ingot. Some differences / similarities between structure formation during solidification of the steel static ingot and virtual brass

static ingot are studied. The developed method allows to predict the following structural zones: fine columnar grains zone, (FC), columnar

grains zone, (C), equiaxed grains zone, (E). The FCCT-transformation and CET-transformation are forecast as sharp transitions of the

analyzed structures. Similarities between steel static ingot morphology and that predicted for the virtual brass static ingot are described.

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Preliminary tests aimed at obtaining a cellular SiC/iron alloy composite with a spatial structure of mutually intersecting skeletons, using a

porous ceramic preform have been conducted. The possibility of obtaining such a composite joint using a SiC material with an oxynitride

bonding and grey cast iron with flake graphite has been confirmed. Porous ceramic preforms were made by pouring the gelling ceramic

suspension over a foamed polymer base which was next fired. The obtained samples of materials were subjected to macroscopic and

microscopic observations as well as investigations into the chemical composition in microareas. It was found that the minimum width of a

channel in the preform, which in the case of pressureless infiltration enables molten cast iron penetration, ranges from 0.10 to 0.17 mm. It

was also found that the ceramic material applied was characterized by good metal wettability. The ceramics/metal contact area always has

a transition zone (when the channel width is big enough), where mixing of the components of both composite elements takes place.

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The paper presents influence of soaking parameters (temperature and time) on structure and mechanical properties of spheroidal graphite

nickel-manganese-copper cast iron, containing: 7.2% Ni, 2.6% Mn and 2.4% Cu. Raw castings showed austenitic structure and relatively

low hardness (150 HBW) guaranteeing their good machinability. Heat treatment consisted in soaking the castings within 400 to 600°C for

2 to 10 hours followed by air-cooling. In most cases, soaking caused changes in structure and, in consequence, an increase of hardness in

comparison to raw castings. The highest hardness and tensile strength was obtained after soaking at 550°C for 6 hours. At the same time,

decrease of the parameters related to plasticity of cast iron (elongation and impact strength) was observed. This resulted from the fact that,

in these conditions, the largest fraction of fine-acicular ferrite with relatively high hardness (490 HV0.1) was created in the matrix. At

lower temperatures and after shorter soaking times, hardness and tensile strength were lower because of smaller degree of austenite

transformation. At higher temperatures and after longer soaking times, fine-dispersive ferrite was produced. That resulted in slightly lower

material hardness.

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High-tin bronzes are used for church bells and concert bells (carillons). Therefore, beside their decorative value, they should also offer

other functional properties, including their permanence and good quality of sound. The latter is highly influenced by the structure of bell

material, i.e. mostly by the presence of internal porosity which interferes with vibration of the bell waist and rim, and therefore should be

eliminated. The presented investigations concerning the influence of tin content ranging from 20 to 24 wt% on mechanical properties of

high-tin bronzes allowed to prove the increase in hardness of these alloys with simultaneous decrease in the tensile and the impact

strengths (Rm and KV, respectively) for the increased tin content. Fractures of examined specimens, their porosity and microstructures

were also assessed to explain the observed regularities. A reason of the change in the values of mechanical properties was revealed to be

the change in the shape of α-phase crystals from dendritic to acicular one, and generation of grain structure related to the increased Sn

content in the alloy.

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The study includes the results of research conducted on selected lead-free binary solder alloys designed for operation at high temperatures.

The results of qualitative and quantitative metallographic examinations of SnZn alloys with various Zn content are presented. The

quantitative microstructure analysis was carried out using a combinatorial method based on phase quanta theory, per which any

microstructure can be treated as an array of elements disposed in the matrix material. Fatigue tests were also performed using the

capabilities of a modified version of the LCF method hereinafter referred to in short as MLCF, which is particularly useful in the

estimation of mechanical parameters when there are difficulties in obtaining many samples normally required for the LCF test. The fatigue

life of alloys was analyzed in the context of their microstructure. It has been shown that the mechanical properties are improved with the

Zn content increasing in the alloy. However, the best properties were obtained in the alloy with a chemical composition close to the

eutectic system, when the Zn-rich precipitates showed the most preferred morphological characteristics. At higher content of Zn, a strong

structural notch was formed in the alloy because of the formation in the microstructure of a large amount of the needle-like Zn-rich

precipitates deteriorating the mechanical characteristics. Thus, the results obtained during previous own studies, which in the field of

mechanical testing were based on static tensile test only, have been confirmed. It is interesting to note that during fatigue testing, both

significant strengthening and weakening of the examined material can be expected. The results of fatigue tests performed on SnZn alloys

have proved that in this case the material was softened.

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The study presents the results of the investigations of the effect of Cu, Ni, Cr, V, Mo and W alloy additions on the microstructure and

mechanical properties of the AlSi7Mg0.3 alloy. The examinations were performed within a project the aim of which is to elaborate an

experimental and industrial technology of producing elements of machines and devices complex in their construction, made of aluminium

alloys by the method of precision investment casting. It was demonstrated that a proper combination of alloy additions causes the

crystallization of complex intermetallic phases in the silumin, shortens the SDAS and improves the strength properties: Rm, Rp0.2,HB

hardness. Elevating these properties reduces At, which, in consequence, lowers the quality index Q of the alloy of the obtained casts.

Experimental casts were made in ceramic moulds preliminarily heated to 160 °C, into which the AlSi7Mg0.3 alloy with the additions was

cast, followed by its cooling at ambient temperature. With the purpose of increasing the value of the quality index Q, it is recommended

that the process of alloy cooling in the ceramic mould be intensified and/or a thermal treatment of the casts be performed (ageing)(T6).

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Wear resistance of TiC-cast steel metal matrix composite has been investigated. Composites were obtained with SHSB method known as

SHS synthesis during casting. It has been shown the differences in wear between composite and base cast steel. The Miller slurry

machine test were used to determine wear loss of the specimens. The slurry was composed of SiC and water. The worn surface of

specimens after test, were studied by SEM. Experimental observation has shown that surface of composite zone is not homogenous and

consist the matrix lakes. Microscopic observations revealed the long grooves with SiC particles indented in the base alloy area, and

spalling pits in the composite area. Due to the presence of TiC carbides on composite layer, specimens with TiC reinforced cast steel

exhibited higher abrasion resistance. The wear of TiC reinforced cast steel mechanism was initially by wearing of soft matrix and in

second stage by polishing and spalling of TiC. Summary weight loss after 16hr test was 0,14÷0,23 g for composite specimens and 0,90 g

for base steel

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The article presents crystallization process of silicon molybdenum ductile cast iron (SiMo). The alloy with 5% silicon content and with

variable amounts of Mo in a range of 0-1% was chosen for the research. The carbon content in the analysed alloys did not exceed 3,1%.

The studies of crystallization process were based on thermal – derivative analysis (TDA). Chemical composition of all examined samples

was analysed with the use of LECO spectrometer. Additionally, the carbon and the sulphur content was determined basing on carbon and

sulphur LECO analyser. For metallographic examination, the scanning electron microscopy (SEM) with EDS analyser was used. Disclosed

phases have been also tested with the use of X-ray diffraction. The results allowed the description of crystallization processes of silicon

molybdenum ductile cast iron using thermal – derivative analysis (TDA). Conducted studies did not allow for the clear identification of all

complex phases containing molybdenum, occurring at the grain boundaries. Therefore, the further stages of the research could include the

use of a transmission electron microscope to specify the description of complex compounds present in the alloy.

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This paper presents the results of hypoeutectic 226 grade alloy as well as prepared on its basis Al-Si alloy containing Cr, V and Mo. The

additives tested were added as AlCr15, AlV10 and AlMo8 master alloys. Alloys tested were poured into DTA sampler as well as using

pressure die casting. An amount of Cr, V and Mo additives in alloy poured into DTA sampler comprised within the range approximately

0.05-0.35%. Alloys to pressure die casting contained 0.05-0.20% Cr, V and Mo. The crystallization process was examined using the derivative

thermal analysis (DTA). The microstructure of castings made in the DTA sampler as well as castings made with use of pressure die

casting were examined. The basic mechanical properties of castings made using pressure die casting were defined too. It has been shown

in the DTA curves of Al-Si alloy containing approximately 0.30 and 0.35% Cr, Mo, and V there is an additional thermal effect probably

caused by a peritectic crystallization of intermetallic phases containing the aforementioned additives. These phases have a morphology

similar to the walled and a relatively large size. The analogous phases also occur in pressure die casting alloys containing 0.10% or more

additions of Cr, V and Mo. The appearance of these phases in pressure die casting Al-Si alloys coincides with a decrease in the value of

the tensile strength Rm and the elongation A. It has been shown die castings made of Al-Si alloys containing the aforementioned additives

have a higher Rm and A than 226 alloy.

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It is well-known that the better the control of the liquid aluminium allows obtaining of better properties. One of the most important defects

that is held responsible for lower properties has been the presence of porosity. Porosity has always been associated with the amount of

dissolved hydrogen in the liquid. However, it was shown that hydrogen was not the major source but only a contributor the porosity. The

most important defect that causes porosity is the presence of bifilms. These defects are surface entrained mainly due to turbulence and

uncontrolled melt transfer. In this work, a cylindrical mould was designed (Ø30 x 300 mm) both from sand and die. Moulds were produced

both from sand and die. Water cooled copper chill was placed at the bottom of the mould in order to generate a directional solidification.

After the melt was prepared, prior to casting of the DC cast samples, reduced pressure test sample was taken to measure the melt quality

(i.e. bifilm index). The cast parts were then sectioned into regions and longitudinal and transverse areas were investigated

metallographically. Pore size, shape and distribution was measured by image analysis. The formation of porosity was evaluated by means

of bifilm content, size and distribution in A356 alloy.

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The paper presents the possibility of application of the developed computer script which allows the assessment of non-equilibrium

solidification of binary alloys in the ThermoCalc program. The script makes use of databases and calculation procedures of the POLY-3

module. A solidification model including diffusion in the solid state, developed by Wołczyński, is used to describe the non-equilibrium

solidification. The model takes into account the influence of the degree of solute segregation on the solidification process by applying the

so-called back-diffusion parameter. The core of the script is the iteration procedure with implemented model equation. The possibility of

application of the presented calculation method is illustrated on the example of the Cr-30% Ni alloy. Computer simulations carried out

with use of the developed script allow to determine the influence of the back-diffusion parameter on the course of solidification curves,

solidus temperature, phase composition of the alloy and the fraction of each phase after the solidification completion, the profile of solute

concentration in liquid during solidification process, the average solute concentration in solid phase at the eutectic temperature and many

other quantities which are usually calculated in the ThermoCalc program.

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Abstrakt

The paper presents the production problems related to casting using precision casting methods. The essential adverse effect of the casting

process is the presence of burrs understood as oversize material necessary to remove the next finishing operations. In addition, the surfaces

of the cast often characterized by a porous structure. One of the methods to improve the smoothness of the area proposed by the authors is

the use of vibro-abrasive finishing. This type of treatment is widely used in the treatment of finishing small objects as well as complex

shapes. Objects in the form of casting in the first step was treated with aggressive deburring polyester matrix abrasive media. The second

stage was polishing, with using smoothing porcelain media. The study evaluated the effect of vibro-abrasive machining typical cast on the

basic parameters of the geometric structure of the surface. Observations using optical microscope Nicon Eclipse MA 200 compared

changes in surface microstructure and the effect of deburring. Clearly we can say that vibro-abrasive machining an effective way

of reducing the size of burrs, smoothing and lightening the surface of objects made by casting.

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Abstrakt

Metal casting process involves processes such as pattern making, moulding and melting etc. Casting defects occur due to combination of

various processes even though efforts are taken to control them. The first step in the defect analysis is to identify the major casting defect

among the many casting defects. Then the analysis is to be made to find the root cause of the particular defect. Moreover, it is especially

difficult to identify the root causes of the defect. Therefore, a systematic method is required to identify the root cause of the defect among

possible causes, consequently specific remedial measures have to be implemented to control them. This paper presents a systematic

procedure to identify the root cause of shrinkage defect in an automobile body casting (SG 500/7) and control it by the application of

Pareto chart and Ishikawa diagram. with quantitative Weightage. It was found that the root causes were larger volume section in the cope,

insufficient feeding of riser and insufficient poured metal in the riser. The necessary remedial measures were taken and castings were

reproduced. The shrinkage defect in the castings was completely eliminated.

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Abstrakt

Investigations were carried out to ensure the granulated blast furnace (GBF) slag as an alternative mould material in foundry industry by

assessing the cast products structure property correlations. Sodium silicate-CO2 process was adopted for preparing the moulds. Three

types of moulds were made with slag, silica sand individually and combination of these two with 10% sodium silicate and 20 seconds CO2

gassing time. A356 alloy castings were performed on these newly developed slag moulds. The cast products were investigated for its

metallography and mechanical properties. Results reveal that cast products with good surface finish and without any defects were

produced. Faster heat transfers in slag moulds enabled the cast products with fine and refined grain structured; and also, lower Secondary

Dendrite Arm Spacing (SDAS) values were observed than sand mould. Slag mould casting shows improved mechanical properties like

hardness, compression, tensile and impact strength compared to sand mould castings. Two types of tensile fracture modes, namely

cleavage pattern with flat surfaces representing Al−Si eutectic zone and the areas of broken Fe-rich intermetallic compounds which appear

as flower-like morphology was observed in sand mould castings. In contrast, GBF slag mould castings exhibit majority in dimple fracture

morphology with traces of cleavage fracture. Charpy impact fractured surfaces of sand mould castings shows both transgranular and

intergranular fracture modes. Only intergranular fracture mode was noticed in both GBF slag and mixed mould castings.

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Abstrakt

Cast stainless steel of the Cr-Ni duplex type is used, among others, for the cast parts of pumps and valves handling various chemically

aggressive media. Therefore, the main problem discussed in this article is the problem of abrasion wear resistance in a mixture of SiC and

water and resistance to electrochemical corrosion in a 3% NaCl- H2O solution of selected cast steel grades, i.e. typical duplex cast steel,

high silicon and manganese duplex cast steel, and Cr-Ni austenitic cast steel (type AISI 316L). The study shows that the best abrasion

wear resistance comparable to Ni-Hart cast iron was obtained in the cast duplex steel, where Ni was partially replaced with Mn and N.

This cast steel was also characterized by the highest hardness and matrix microhardness among all the tested cast steel grades. The best

resistance to electrochemical corrosion in 3% NaCl- H2O solution showed the cast duplex steel with high content of Cr, Mo and N. The

addition of Ni plays rather insignificant role in the improvement of corrosion resistance of the materials tested.

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Abstrakt

The results of investigations of the rheological properties of typical ceramic slurries used in the investment casting technology – the lost

wax technology are presented in the paper. Flow curves in the wide range of shear velocity were made. Moreover, viscosity of ceramic

slurries depending on shearing stresses was specified. Tests were performed under conditions of three different temperatures 25, 30 and

35oC, which are typical and important in the viewpoint of making ceramic slurries in the investment casting technology.

In the light of the performed investigations can be said that the belonging in group of Newtonian or Non – Newtonian fluid is dependent

on content of solid phase (addition of aluminum oxide) in the whole composition of liquid ceramic slurries.

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This paper discusses the joining of AZ91 magnesium alloy with AlSi17 aluminium alloy by compound casting. Molten AZ91 was cast at

650oC onto a solid AlSi17 insert placed in a steel mould under normal atmospheric conditions. Before casting, the mould with the insert

inside was heated up to about 370oC. The bonding zone forming between the two alloys because of diffusion had a multiphase structure

and a thickness of about 200 µm. The microstructure and composition of the bonding zone were analysed using optical microscopy,

scanning electron microscopy and energy dispersive X-ray spectroscopy. The results indicate that the bonding zone adjacent to the AlSi17

alloy was composed of an Al3Mg2 intermetallic phase with not fully consumed primary Si particles, surrounded by a rim of an Mg2Si

intermetallic phase and fine Mg2Si particles. The bonding zone near the AZ91 alloy was composed of a eutectic (an Mg17Al12 intermetallic

phase and a solid solution of Al and Si in Mg). It was also found that the compound casting process slightly affected the AZ91alloy

microstructure; a thin layer adjacent to the bonding zone of the alloy was enriched with aluminium.

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Abstrakt

In order for the working status of the aluminum alloyed hydraulic valve body to be controlled in actual conditions, a new friction and wear

design device was designed for the cast iron and aluminum alloyed valve bodies comparison under the same conditions. The results

displayed that: (1) The oil leakage of the aluminum alloyed hydraulic valve body was higher than the corresponding oil leakage of the iron

body during the initial running stage. Besides during a later running stage, the oil leakage of the aluminum alloyed body was lower than

corresponding oil leakage of the iron body; (2) The actual oil leakage of different materials consisted of two parts: the foundation leakage

that was the leakage of the valve without wear and wear leakage that was caused by the worn valve body; (3) The aluminum alloyed valve

could rely on the dust filling furrow and melting mechanism that led the body surface to retain dynamic balance, resulting in the valve

leakage preservation at a low level. The aluminum alloy modified valve body can meet the requirements of hydraulic leakage under

pressure, possibly constituting this alloy suitable for hydraulic valve body manufacturing.

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Abstrakt

Defects affect the properties and behavior of the casting during its service life. Since the defects can occur due to different reasons, they

must be correctly identified and categorized, to enable applying the appropriate remedial measures. several different approaches for

categorizing casting defects have been proposed in technical literature. They mainly rely on physical description, location, and formation

of defects. There is a need for a systematic approach for classifying investment casting defects, considering appropriate attributes such as

their size, location, identification stage, inspection method, consistency, appearance of defects. A systematic approach for categorization of

investment casting defects considering multiple attributes: detection stage, size, shape, appearance, location, consistency and severity of

occurrence. Information about the relevant attributes of major defects encountered in investment casting process has been collected from

an industrial foundry. This has been implemented in a cloud-based system to make the system freely and widely accessible.

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The article presents a study on the effectiveness of the foundries using Data Envelopment Analysis (DEA) method. The aim of the article

is to analyze the usefulness of DEA method in the study of the relative efficiency of the foundries. DEA is a benchmarking technique

based on linear programming to evaluate the effectiveness of the analyzed objects. The research was conducted in four Polish and two

foreign plants. Evaluated foundries work in similar markets and have similar production technology. We created a DEA model with two

inputs (fixed assets and employment) and one output (operating profit). The model was produced and solved using Microsoft Excel

together with its Solver add-in. Moreover, we wrote a short VBA script to perform automating calculations. The results of our study

include a benchmark and foundries’ ranking, and directions to improve the efficiency of inefficient units. Our research has shown that

DEA can be a very valuable method for evaluating the efficiency of foundries.

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Abstrakt

The paper presents an analysis of the effect of shape of primary silicon crystals on the sizes of stresses and deformations in a surface layer

of A390.0 alloy by Finite Elements Method (FEM). Analysis of stereological characteristics of the studied alloy, performed based on a

quantitative metallographic analysis in combination with a statistical analysis, was used for this purpose. The presented simulation tests

showed not only the deposition depth of maximum stresses and strains, but also allowed for determining the aforementioned values

depending on the shape of the silicon crystals. The studied material is intended for pistons of internal combustion engines, therefore the

analysis of the surface layer corresponded to conditions during friction in a piston-cylinder system of an internal combustion engine having

power of up to 100 kW. The obtained results showed important differences in the values of stresses and strains up to 15% between various

shape of the silicon crystals. Crystals with sharp edges caused higher stresses and deformation locally than those with rounded shapes.

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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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