The aging granulate is to activate the blowing agent during the manufacturing process to granulate models can re-expand and shape the
model of well-sintered granules, smooth surface and a suitable mechanical strength.
The article presents the results of studies which aim was to determine the optimum time for aging pre-foamed granules for pre-selected
raw materials.
The testing samples were shaped in an autoclave, with constant parameters sintering time and temperature. Samples were made at 30
minute intervals. Models have been subjected to flexural strength and hardness.
The article presents the results of the research on the influence of the shape of reaction chamber on spheroidisation of cast iron produced with use of the inmold method. The amounts of nodular graphite precipitates in castings produced with the use of different reaction chambers have been compared.
The article presents analysis of the influence of ingate size on the Lost Foam casting process. In particular, analysis of simulation tests has been carried out to determine the ingate size influence on the rate of filling of the mould cavity, pressure in the gas gap and size of the gas gap. A specially prepared mathematical model of the process and an original calculation algorithm were used in simulation tests of full-mould casting. The tests have indicated that the increase of the ingate size results in the increase of filling rate and increase of pressure of gases in the gas gap. However, significant influence on mould cavity filling occurs only when the ingate size is less than ~1 cm2.
.
This work presents the analysis of the final shaping process of the patterns aimed at determining the influence of the pressure and the time of sintering on the resistance to bending. The analysis of the research results proved that when the pressure of the sintering rises and reaches Ps=2.1 bar the resistance to bending increases, above this level of the pressure the resistance value starts decreasing. The time of styrofoam sintering at which the highest bending resistance values were obtained is ts=90 s. When the sintering pressure is less than 2 bar prolongation of the time of sintering over 90 s causes a slight increase in the resistance, however, at higher pressures prolongation of the time of sintering causes submelting of the styrofoam pattern.
The paper presents the results of the crystallization process of silumin by the TDA thermographic method and the results of the cast
microstructure obtained in the sampler ATD-10, that was cooling down in ambient air. The study was conducted for silumins AlSi8 and
AlSi11 unmodified. The work demonstrated that the use of thermal imaging camera allows for the measurement and recording the
solidification process of silumin. Thermal curve was registered with the infrared camera and derivative curve that was calculated on the
base of thermal curve have both a very similar shape to adequate them TDA curves obtained from measurements using a thermocouple.
Test results by TDA thermographic method enable quantitative analysis of the kinetics of the cooling and solidification process of hypoand
neareutectic silumins.
This work presents the technology of making foam plastics patterns used in casting as well as the final shaping stand. The analysis of the sintering process was carried out aiming at determining the influence of the pressure and the time of sintering on the flexural strength properties. The analysis of the research results confirmed that when the sintering pressure grows to the value of Pa =1,7 bar the flexural strength also increases, when the pressure value is higher than that, the degradation of the material takes place and the strength properties decrease.
The work is a part of research into the reduction of energy consumption in the production of EPSthrough the modernization
of technological equipment used. This paper presents the results of research and analysis of heat transfer process between the water vapor
that was provided to machine, the mold, the product and the environment. The paper shows the calculation of the heat balance of the
production cycle for two types of mold: standard and modernized. The performance tests used an infrared imaging camera.
The results were used to develop a computer image analysis and statistical analysis. This paper presents the main stages of the production
process and the construction of technological equipment used, changing the mold surface temperature field during the production cycle
and the structure of the heat balance for the mold and its instrumentation. It has been shown that the modernization of construction
of technological equipment has reduced the temperature field and as a consequence of decreased of demand for process steam production
cycle.
The work is a continuation of research concerning the influence of intensive cooling of permanent mold in order to increase the casting
efficiency of aluminium alloys using the multipoint water mist cooling system. The paper presents results of investigation of crystallization
process and microstructure of synthetic hypereutectic alloys: AlSi15 and AlSi19. Casts were made in permanent mold cooled with water
mist stream. The study was conducted for unmodified silumins on the research station allowing the cooling of the special permanent probe
using a program of computer control. Furthermore the study used a thermal imaging camera to analyze the solidification process of
hypereutectic silumins. The study demonstrated that the use of mold cooled with water mist stream allows in wide range the formation of
the microstructure of hypereutectic silumins. It leads to higher homogeneity of microstructure and refinement of crystallizing phases and
also it increases subsequently the mechanical properties of casting.
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.
The work is a continuation of research concerning the influence of intensive cooling of permanent mold in order to increase the casting
efficiency of aluminium alloys using the multipoint water mist cooling system. The paper presents results of investigation of crystallization
process and microstructure of multicomponent synthetic hypereutectic alloy AlSi20CuNiCoMg. The study was conducted for unmodified
silumin on the research station allowing the cooling of the special permanent sampler using a program of computer control. Furthermore,
the study used a thermal imaging camera to analyze the solidification process of multicomponent alloy. The study demonstrated that the
use of mold cooled with water mist stream allows in wide range to form the microstructure of hypereutectic multicomponent silumin. It
leads to higher homogeneity of microstructure and refinement of crystallizing phases of casting.
The article presents the investigations of 7xxx aluminium alloys performed by the method of thermal and derivational analysis. The studies made it possible to identify the effect of the changes in the Cu concentration, the total Zn and Mg weight concentrations and the Zn/Mg weight concentration ratio on their crystallization process: the cooling as well as the kinetics and dynamics of the thermal process of cooling and crystallization. Metallographic studies were performed on the microstructure of the examined alloys and their HB hardness was measured. The evaluation of the changes was presented in reference to the model alloys EN AW-7003 and EN AW-7010, whose microstructure under the conditions of thermodynamic equilibrium are described by the phase diagrams: Al-Zn-Mg and Al-Zn-Mg-Cu. The performed investigations confirmed that the hardness HB of the examined alloys is mainly determined by the reinforcement of the matrix αAl by the introduced alloy additions and the presence of phases Θ(Al2Cu) and S(Al2CuMg) rich in copper, as well as η(MgZn2), in the examined alloys' microstructure. The increase of the amount of intermetallic phases precipitated in the microstructure of the examined alloys is caused, beside Cu, by the characteristic change of Zn wt. concentration and Mg. It was proposed that the process of one-stage thermal treatment of the examined alloys be introduced at a temperature of up to tJ-20 °C, which will prevent the exceedance of the solidus temperature.
The work presents the results of the investigations of the effect of the nitrogen (N2) refining time „τraf” and the gas output on the course of
the crystallization process, the microstructure and the gassing degree of silumin 226 used for pressure casting. The refinement of the
examined silumin was performed with the use of a device with a rotating head. The crystallization process was examined by way of
thermal analysis and derivative analysis TDA. The performed examinations showed that the prolongation of the N2 refining time causes
a significant rise of the temperature of the crystallization end of the silumin, „tL”, as well as a decrease of its gassing degree, „Z”. An
increase of the nitrogen output initially causes an increase of the temperature „tL” and a drop of the gassing degree „Z”, which reach their
maximal values with the output of 20 dm3
/min. Further increase of the output causes a decrease of the value „tL” and an increase of „Z”.
The examined technological factors of the refining process did not cause any significant changes in the microstructure of silumin 226.
The study discusses the issues connected with the production of thin-walled ceramic slurry in the replicast cs technology. In the ceramic mould production process, a special role is played by the liquid ceramic slurry used to produce the first layer of the mould. The study examines selected technological properties of liquid ceramic slurries used to produce moulds in the replicas cs technology. The ceramic slurries for the tests were prepared based on the binders Ludox Px30 and Sizol 030, enriched with Refracourse flour. The wettability of the pattern's surface by the liquid ceramic slurry and the dependence of the apparent viscosity on the ceramic flour content in the mixture were determined. The wettability of the pattern surface by the liquid ceramic slurry was determined based on the measurement of the wetting angle. The angle was determined by means of an analysis of the computer image obtained with the use of a CDC camera.
Metallographic investigations and a computer simulation of stresses in a gravity die-casting bushing were performed. Simulation of the casting process, solidification of the thick-walled bushing and calculations of the stress was performed using MAGMA5.3 software. The size variability of phases κIIaffecting the formation of phase stresses σf, depending on the location of the metallographic test area, was identified. The distribution of thermal σtand shrinkage stresses σs, depending on the location of the control point SC in the bushing's volume, was estimated. Probably the nature of these stresses will change slightly even after machining. This can cause variations in operating characteristics (friction coefficient, wear). Due to the strong inhomogeneity of the stress distribution in the bushing's casting, it is necessary to perform further tests of the possibility to conduct thermal treatment guaranteeing homogenization of the internal stresses in the casting, as well as to introduce changes in the bushing's construction and the casting technology. The paper presents the continuation of the results of research aimed at identifying the causes of defects in the thick-walled bushing, die-casting made of CuAl10Fe5Ni5Cr aluminium bronze.
This paper presents the effect of the temperature and hold time in the holding furnace of 226 silumin on the characteristic quantities of
TDA curves. The temperature of phase transformations and the cooling rate were tested.It has been shown that increasing both the hold
time and the temperature in the holdingfurnace cause the decreasethe end ofα+Al9Fe3Si2+β and α+Al2Cu+βternary eutectics
crystallizationtemperature in the tested silumin. This is due to the fact an increase in amounts of impurities as a result of reacting theliquid
alloy with the gases contained in the air.It has been shown, however, that examined technological factors ofthe metal preparation do not
cause systematic changes in the cooling rate.
The work presents the effect of strontium and antimony modification on the microstructure and mechanical properties of 226 silumin casts.
The performed research demonstrated that strontium causes high refinement of silicon precipitations in the eutectic present in the microstructure
of the examined silumin and it significantly affects the morphology of eutectic silicon from the lamellar to the fibrous one. Sr
modification also causes an increase of: the tensile strength „Rm” by 12%; the proof stress „Rp0,2” by 5%; the unit elongation „A” by 36%
and the hardness HB by 13%. Antimony did not cause a change in the microstructure of the silumin, yet it caused an increase in Rm and
HB by 5%, in Rp0,2 by 7% and in A by 4%.
The paper presents the results of hypoeutectic silumin 226 grade and silumin produced on its basis through the addition of V and Mo.
Vanadium and molybdenum were added as the preliminary alloy AlV10 and AlMo8 in an amount providing the concentration of 0.1; 0.2;
0.3 and 0.4% V and Mo. TDA curves of tested silumins were presented; regardless of the chemical composition there were similar thermal
effects. Pressure castings microstructure research revealed the presence in silumins with the addition of V and Mo phases do not occur in
silumin without these additives. These phases have a morphology similar to the walled, and their size increases with increasing
concentration of V and Mo. The size of the precipitates of these phases silumin containing 0.1% V and Mo does not exceed 10 microns,
while 0.4% of the content of these elements increases to about 80 microns. Tests of basic mechanical properties of silumins were carried
out. It has been shown that the highest values of tensile strength Rm = 295 MPa and elongation A = 4.2% have silumin containing
approximately 0.1% V and Mo. Increasing concentrations of these elements causes a gradual lowering of the Rm and A values.
The paper presents the technology and organization of the artistic cast production. On the basis of the actual cast production system, the
manufacturing process was shown, in particular sand–piece moulding, which is a very important process and a time-consuming part of the
entire manufacture of the casts. The current state of the production process as well as the organization of the work and production
technology were analysed with the use of methods and techniques of production improvement, the Lean Manufacturing concept and
computer systems. The results of the analysis and studies were shown with use of schemes and graphs of the layout of the production
resources, a flow chart of the production process, value stream mapping, and a costs table for the production and modernization of the
moulding stage. The work has shown that there are possibilities to improve the artistic cast production system. This improvement leads to
increased productivity, lower production costs of artistic casts and increased competitiveness of the foundry.
This work presents the results of the research of the effect of the inoculant Emgesal Flux 5 on the microstructure of the magnesium alloy AZ91. The concentration of the inoculant was increased in samples in the range from 0.1% to 0.6%. The thermal processes were examined with the use of Derivative and Thermal Analysis (DTA). During the examination, the DTA samplers were preheated up to 180 °C. A particular attention was paid to finding the optimum amount of inoculant, which would cause fragmentation of the microstructure. The concentration of each element was verified by means of a spark spectrometer. In addition, the microstructures of the samples were examined with the use of an optical microscope, and an image analysis with a statistical analysis using the NIS–Elements program were carried out. Those analyses aimed at examining the differences between the grain diameters of phase αMg and eutectic αMg+γ(Mg17Al12) in the prepared samples as well as the average size of each type of grain by way of measuring their perimeters. This paper is an introduction to a further research of grain refinement in magnesium alloys, especially AZ91. Another purpose of this research is to achieve better microstructure fragmentation of magnesium alloys without the related changes of the chemical composition, which should improve the mechanical properties.
The current work presents and describes the test bench for analyzing the lost foam process, especially measuring of the pressure of gases in the gas gap and continuous measuring of the rate of rise of the bath level when pouring the liquid metal into the mould. A series of preliminary research was carried out on the bench which was aimed at determining the influence of the basic parameters of the process, i.e. the density of the styrofoam pattern, thickness of the refractory coating applied on the pattern, kind of the alloy and the temperature of pouring on the mould cavity by the liquid metal and the pressure of gases in the gas gap.
For the die casting conditions of aluminium bronzes assumed based on the literature data, a thick-walled bush was cast, made of complex
aluminium bronze (Cu-Al-Fe-Ni-Cr). After the cast was removed from the mould, cracks were observed inside it. In order to identify the
stage in the technological production process at which, potentially, the formation of stresses damaging the continuity of the microstructure
created in the cast was possible (hot cracking and/or cold cracking), a computer simulation was performed. The article presents the results
of the computer simulation of the process of casting the material into the gravity die as well as solidifying and cooling of the cast in the
shape of a thick-walled bush. The simulation was performed with the use of the MAGMA5 program and by application of the
CuAl10Ni5,5Fe4,5 alloy from the MAGMA5 program database. The results were compared with the location of the defects identified in
the actual cast. As a result of the simulation of the die-casting process of this bush, potential regions were identified where significant
principal stresses accumulate, which can cause local hot and cold cracking. Until now, no research has been made of die-cast aluminium
bronzes with a Cr addition. Correlating the results of the computer simulation validated by the analysis of the actual cast made it possible
to clearly determine the critical regions in the cast exposed to cracking and point to the causes of its occurrence. Proposals of changes in
the bush die casting process were elaborated, in order to avoid hot tearing and cold cracking. The article discusses the results of
preliminary tests being a prologue to the optimization of the die-casting process parameters of complex aluminium bronze thick-walled
bushs.
This article presents the results of studies in the hypoeutectic silumin destined for pressure die casting with the simultaneous addition of
chromium and tungsten. The study involved the derivative and thermal analysis of the crystallization process, metallographic analysis and
mechanical properties testing. Silumin 226 grade was destined for studies. It is a typical silumin to pressure die casting. AlCr15 and AlW8
preliminary alloys were added to silumin. Its quantity allowed to obtain 0.1, 0.2, 0.3 and 0.4% of Cr and W in the tested alloy. Studies of
the crystallization process as well as the microstructure of the silumin poured into DTA sampler allowed to state the presence of additional
phase containing 0.2% or more Cr and W. It has not occurred in silumin without the addition of above mentioned elements. It is probably
the intermetallic phase containing Cr and W. DTA studies have shown this phase crystallizes at a higher temperature range than α (Al)
solid solution. In the microstructure of each pressure die casting containing Cr and W the new phases formed. Mechanical properties tests
have shown Cr and W additives in silumin in an appropriate amount may increase its tensile strength Rm (about 11%), the yield strength
Rp0.2 (about 21%) and to a small extent elongation A.