The paper presents the method of preparing a composite slurry composed of AlSi11 alloy matrix and 10 vol.% of SiC particles, as well as
the method of its high-pressure die casting and the measurement results concerning the castability of the obtained composite. Composite
castings were produced at various values of the piston velocity in the second stage of injection, diverse intensification pressure values, and
various injection gate width values. There were found the regression equations describing the change of castability of the examined
composite as a function of pressure die casting process parameters. The conclusion gives the analysis and the interpretation of the obtained
results.
The measurement results concerning the abrasive wear of AlSi11-SiC particles composites are presented in paper. The method of
preparing a composite slurry composed of AlSi11 alloy matrix and 10, 20% vol.% of SiC particles, as well as the method of its highpressure
die casting was described. Composite slurry was injected into metal mould of cold chamber pressure die cast machine and
castings were produced at various values of the piston velocity in the second stage of injection, diverse intensification pressure values, and
various injection gate width values. Very good uniform arrangement of SiC particles in volume composite matrix was observed and these
results were publicated early in this journal. The kinetics of abrasive wear and correlation with SiC particles arrangement in composite
matrix were presented. Better wear resistance of composite was observed in comparison with aluminium alloy. Very strong linear
correlation between abrasive wear and particle arrangement was observed. The conclusion gives the analysis and the interpretation of the
obtained results.
The paper presents the method of preparing a composite slurry composed of AlSi11 alloy matrix and 10 vol.% of SiC particles, as well as
the method of its high-pressure die casting and the measurement results concerning the tensile strength, the yield point, the elongation and
hardness of the obtained composite. Composite castings were produced at various values of the piston velocity in the second stage of
injection, diverse intensification pressure values, and various injection gate width values. There were found the regression equations
describing the change of mechanical properties of the examined composite as a function of pressure die casting process parameters. The
conclusion gives the analysis and the interpretation of the obtained results.
Final quality of casts produced in a die casting process represents a correlation of setting of technological parameters of die casting cycle, properties of alloy, construction of a die and structure of gating and of bleeding systems. Suitable structure of a gating system with an appertaining bleeding system of the die can significantly influence mechanical and structural properties of a cast. The submitted paper focuses on influence of position of outfall of an gate into the cast on its selected quality properties. Layout of the test casts in the die was designed to provide filling of a shaping cavity by the melt with diverse character of flowing. Setting of input technological parameters during experiment remained on a constant level. The only variable was the position of the gate. Homogeneity represented by porosity f and ultimate strength Rm were selected to be the assessed representative quality properties of the cast. The tests of the influence upon monitored parameters were realized in two stages. The test gating system was primarily subjected to numerical tests with the utilization of a simulation program NovaFlow&Solid. Consequently, the results were verified by the experimental tests carried out with the physical casts produced during operation. It was proved that diverse placement of the gate in relation to the cast influences the mode of the melt flowing through the shaping cavity which is reflected in the porosity of the casts. The experimental test proved correlation of porosity f of the cast with its ultimate strength Rm. At the end of the paper, the interaction dependencies between the gate position, the mode of filling the die cavity, porosity f and ultimate strength Rm.
The paper reports the results of a physical modelling study of the production of a hypereutectic aluminium alloy to be used for making an alloy vapour source for operation in the magnetron. Within the study, targets from a hypereutectic aluminium-silicon alloy were made in laboratory conditions. Thus obtained material was subjected to heat treatment, porosity analysis, and the assessment of the microstructure and fitness for being used in the magnetron. The process of melting the hypereutectic Al-Si alloy was carried out at the Department of Foundry of the Czestochowa University of Technology. The investigation into the production of the alloy vapour source for the synthesis of the dielectric material from the hypereutectic aluminium alloy has confirmed.
In contemporary high-pressure die casting foundries, the mastery of each sequence in the production cycle is more and more important. In the paper, an example of virtual analysis of gearbox casting from Al alloy will be presented. It includes a large variety of parameters, as follows: choosing of appropriate foundry technology, calculation of computer simulation of casting process which takes into account the filling process of cold chamber and filling of cavity, model description of three phases in high-pressure die casting, flow of molten metal, solidification, formation of stress and deformations. Additionally, the optimization of cooling and heating systems will be compared with calculated volume defects, dimensions of castings and their deformations with experimentally obtained values.
Magnesium alloys are one of the lightest of all the structural materials. Because of their excellent physical and mechanical properties the
alloys have been used more and more often in various branches of industry. They are cast mainly (over 90%) on cold and hot chamber die
casting machines. One of the byproducts of casting processes is process scrap which amounts to about 40 to 60% of the total weight of a
casting. The process scrap incorporates all the elements of gating systems and fault castings. Proper management of the process scrap is
one of the necessities in term of economic and environmental aspects.
Most foundries use the process scrap, which involves adding it to a melting furnace, in a haphazard way, without any control of its content
in the melt. It can lead to many disadvantageous effects, e.g. the formation of a hard buildup at the bottom of the crucible, which in time
makes casting impossible due to the loss of the alloy rheological properties. The research was undertaken to determine the effect of an
addition of the process scrap on the mechanical properties of AZ91 and AM50 alloys. It has been ascertained that the addition of a specific
amount of process scrap to the melt increases the mechanical properties of the elements cast from AZ91 and AM50 alloys.
The increase in the mechanical properties is caused mainly by compounds which can work as nuclei of crystallization and are introduced
into the scrap from lubricants and anti-adhesive agents. Furthermore carbon, which was detected in the process scrap by means of SEM
examination, is a potent grain modifier in Mg alloys [1-3].
The optimal addition of the process scrap to the melt was determined based on the statistical analysis of the results of studies of the effect
of different process scrap additions on the mean grain size and mechanical properties of the cast parts.
Experimental Mg-Al-RE type magnesium alloys for high-pressure die-casting are presented. Alloys based on the commercial AM50
magnesium alloy with 1, 3 and 5 mass % of rare earth elements were fabricated in a foundry and cast in cold chamber die-casting
machines. The obtained experimental casts have good quality surfaces and microstructure consisting of an α(Mg)-phase, Al11RE3,
Al10RE2Mn7 intermetallic compound and small amount of α+γ eutectic and Al2RE phases.
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.
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.
Homogeneity of die castings is influenced by wide range of technological parameters as piston velocity in filling chamber of die casting machine, filling time of mould cavity, temperature of cast alloy, temperature of the mould, temperature of filling chamber, surface pressure on alloy during mould filling, final pressure and others. Based on stated parameters it is clear, that main parameters of die casting are filling time of die mould cavity and velocity of the melt in the ingates. Filling time must ensure the complete filling of the mould cavity before solidification process can negatively influence it. Among technological parameters also belong the returning material, which ratio in charge must be constrained according to requirement on final homogeneity of die castings. With the ratio of returning material influenced are the mechanical properties of castings, inner homogeneity and chemical composition.
Recently, aluminum matrix syntactic foams (AMSFs) have become notably attractive for many different industrial areas like automotive, aerospace, construction and defense. Owing to their low density, good compression response and perfect energy absorption capacity, these advanced composite materials are also considered as strong alternatives to traditional particle reinforced composites and metal foams. This paper presents a promising probability of AMSF fabrication by means of industrial cold chamber die casting method. In this investigation, contrary to other literature studies restricted in laboratory scale, fully equipped custom-build cold chamber die casting machine was used first time and all fabrication steps were designed just as carried out in the real industrial high pressure casting applications. Main casting parameters (casting temperature, injection pressure, piston speed, filler pre-temperature and piston waiting time) were optimized in order to obtain flawless AMSF samples. The density alterations of the syntactic foams were analyzed depending upon increasing process values of injection pressure, piston speed and piston waiting time. In addition, macroscopic and microscopic investigations were performed to comprehend physical properties of fabricated foams. All these efforts showed almost perfect infiltration between filler particles at the optimized injection parameters.
The results of the Charpy impact test of AE-type magnesium alloys produced by the high pressure die casting method are presented. Three alloys with different weight fractions of rare earth elements (RE; e.g. 1, 3 and 5 wt%) and the same mass fraction of aluminium (5 wt%) were prepared. The casts were fabricated using a typical cold chamber high pressure die casting machine with a 3.8 MN locking force. Microstructural analyses were performed by means of a scanning electron microscope (SEM). The impact strength (IS) was determined using a Charpy V hammer with an impact energy equal to 150 J. The microstructure of the experimental alloys consisted of an -Mg solid solution and Al11RE3, Al10Ce2Mn7 and Al2RE intermetallic compounds. The obtained results show the significant influence of the rare earth elements to aluminium ratio on the impact strength of the investigated materials. Lower the RE/Al ratio in the chemical composition of the alloy results in a higher impact strength of the material.
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.
Development of salt cores prepared by high-pressure squeezing and shooting with inorganic binders has shown a high potential of the
given technology even for high-pressure casting of castings. Strength, surface quality of achieved castings, and solubility in water become
a decisive criterion. The shape and quality of grain surface particularly of NaCl – cooking salts that can be well applied without anticaking
additives has shown to be an important criterion. Thus the salt cores technology can cover increasingly growing demands for casting
complexity especially for the automobile industry.
The work presents the investigation results concerning the structure of composite pressure die castings with AlSi11 alloy matrix reinforced
with SiC particles. Examination has been held for composites containing 10 and 20 volume percent of SiC particles. The arrangement of
the reinforcing particles within the matrix has been qualitatively assessed in specimens cut out of the castings. The index of distribution
was determined on the basis of particle count in elementary measuring fields. The tensile strength, the yield point and elongation of the
obtained composite were measured. Composite castings were produced at various values of the piston velocity in the second stage of
injection, diverse intensification pressure values, and various injection gate width values. The regression equation describing the change of
the considered arrangement particles index and mechanical properties were found as a function of the pressure die casting parameters. The
infuence of particle arrangement in composite matrix on mechanical properties these material was examined and the functions of
correlations between values were obtained. The conclusion gives the analysis and the interpretation of the obtained results.
The paper presents some aspects of a development project related to Industry 4.0 that was executed at Nemak, a leading manufacturer of the aluminium castings for the automotive industry, in its high pressure die casting foundry in Poland. The developed data analytics system aims at predicting the casting quality basing on the production data. The objective is to use these data for optimizing process parameters to raise the products’ quality as well as to improve the productivity. Characterization of the production data including the recorded process parameters and the role of mechanical properties of the castings as the process outputs is presented. The system incorporates advanced data analytics and computation tools based on the analysis of variance (ANOVA) and applying an MS Excel platform. It enables the foundry engineers and operators finding the most efficient process variables to ensure high mechanical properties of the aluminium engine block castings. The main features of the system are explained and illustrated by appropriate graphs. Chances and threats connected with applications of the data-driven modelling in die casting are discussed.
This paper presents the results on the effects of die-casting process on the strength parameters of castings of the aluminium AlSi9Cu3 alloy
belonging to the group of EN AB-46000, made on renovated high pressure die-casting machine. Specimens for quality testing were taken
from the places of the casting most loaded during the service. The aim of a research was to prove how the new die-casting process control
capabilities influence on the tensile strength of the cast material defined as a value of the breaking force of the specimens. It has been
found that it is possible to specify a set of recommended settings valves of second (II) and third (III) phase, which are responsible for
filling the metal mould on die-casting pressure machine. From the point of view of the finished cast element, it was noticed that exceeding
the prescribed values of valve settings does not bring further benefits and even causes unnecessary overload and reduce the durability of
the mold. Moreover, it was noticed that reduction of the predetermined setting of the second phase (II) valve leads to the formation of
casting defects again.
The paper presents the results of investigations concerning the influence of negative (relative) pressure in the die cavity of high pressure
die casting machine on the porosity of castings made of AlSi9Cu3 alloy. Examinations were carried out for the VertaCast cold chamber
vertical pressure die casting machine equipped with a vacuum system. Experiments were performed for three values of the applied gauge
pressure: -0.3 bar, -0.5 bar, and -0.7 bar, at constant values of other technological parameters, selected during the formerly carried initial
experiments. Porosity of castings was assessed on the basis of microstructure observation and the density measurements performed by the
method of hydrostatic weighing. The performed investigation allowed to find out that – for the examined pressure range – the porosity of
castings decreases linearly with an increase in the absolute value of negative pressure applied to the die cavity. The negative pressure value
of -0.7 bar allows to produce castings exhibiting porosity value less than 1%. Large blowholes arisen probably by occlusion of gaseous
phase during the injection of metal into the die cavity, were found in castings produced at the negative pressure value of -0.3 bar. These
blowholes are placed mostly in regions of local thermal centres and often accompanied by the discontinuities in the form of interdendritic
shrinkage micro-porosity. It was concluded that the high quality AlSi9Cu3 alloy castings able to work in elevated temperatures can be
achieved for the absolute value of the negative pressure applied to the die cavity greater than 0.5 bar at the applied set of other parameters
of pressure die casting machine work.