The paper present the examination results concerning mechanical properties of castings made of AlSi7MG alloy in correlation both with the most significant squeeze casting parameters and with the modification treatment. Experiments were planned and held according to the 2 3 factorial design. The regression equations describing the influence of the squeeze pressure, the mould temperature, and the quantity of strontium modifier on the strength and elongation of the examined alloy were obtained. It was found that the main factor controlling the strength increase is the squeeze pressure, while the plasticity (A5 ) of the alloy is affected most advantageously by modification. The application of modification treatment in squeeze casting technology enables for production of the slab-type castings made of AlSi7Mg alloy exhibiting strength at the level of 230 MPa and elongation exceeding 14%.

The Mg-RE alloys are attractive, constructional materials, especially for aircraft and automotive industry, thanks to combination of low density, good mechanical properties, also at elevated temperature, and good castability and machinability. Present paper contains results of fatigue resistance test carried out on Elektron 21 magnesium alloy, followed by microstructural and fractographical investigation of material after test. The as-cast material has been heat treated according to two different procedures. The fatigue resistance test has been conducted with 106 cycles of uniaxial, sine wave form stress between 9 MPa and 90 MPa. Fractures of specimens, which ruptured during the test, have been investigated with scanning electron microscope. The microstructure of specimens has been investigated with light microscopy. Detrimental effect of casting defects, as inclusions and porosity, on fatigue resistance has been proved. Also the influence of heat treatment's parameters has been described.

The new investigation method of a permeability of ceramic moulds applied in the investment casting technology, is presented in the paper. Some concepts of performing permeability measurements are shown. Investigations in which the influence of the solid phase fraction in the liquid ceramic moulding sand (LCMS) on a permeability of a multi-layer ceramic mould were performed and discussed. The permeability was estimated during two the most important stages of the technological process: in the first – after wax melting and in the second – after mould annealing. Also an influence of the matrix grain sizes (material for sprinkling) on a ceramic mould permeability was estimated.

Bending strength, thermal and electric conductivity and microstructure examinations of Cu based composite materials reinforced with Saffil alumina fibres are presented. Materials were produced by squeeze casting method applying the designed device and specially elaborated production parameters. Applying infiltration pressure of 90MPa and suitable temperature parameters provided manufacturing of copper based composite materials strengthened with Saffil alumina fibres characterized by the low rest porosity and good fibre-matrix interface. Three point bending tests at temperatures of 25, 100 and 300ºC were performed on specimens reinforced with 10, 15 and 20% of Saffil fibres. Introduced reinforcement effected on the relatively high bending strengths at elevated temperatures. In relation to unreinforced Cu casting strength of composite material Cu – 15vol.% Saffil fibres increase by about 25%, whereas at the highest applied test temperature of 300o C the improvement was almost 100%. Fibres by strengthening of the copper matrix and by transferring loads from the matrix reduce its plastic deformation and hinder the micro-crack developed during bending tests. Decreasing of thermal and electrical conductivity of Cu after incorporating fibres in the matrix are relatively small and these properties can be acceptable for electric and thermal applications.

A technology of sands with water glass hardened by liquid esters is a cheap and ecologic method of producing moulding sands. Due to these advantages, this technology is still very important in several foundry plants for production of heavy iron and steel castings. Reclamation of the mixed moulding and core sands generates significant amounts of dusts, which require further treatments for their reuse. The results of investigations of a pressureless granulation of dusts generated in the dry mechanical reclamation process of the mixture consisting in app. 90 % of moulding sands from the Floster S technology and in 10 % of core sands with phenolic resin resol type, are presented in the hereby paper. Investigations were aimed at obtaining granulates of the determined dimensional and strength parameters. Granules were formed from the mixture of dusts consisting of 75 mass% of dusts after the reclamation of sands mixture and of 25 mass% of dusts from bentonite sands processing plant. Wetted dusts from bentonite sands were used as a binding agent allowing the granulation of after reclamation dusts originated from the mixed sands technology.

The possibility of controlling the solidification and cooling time of castings creates prospects of improving their structure and by the same their properties. Thermal properties of the mould constitute therefore an important factor which is necessary to consider while seeking for the mentioned improvement. The presented work illustrates the method of determining some basic thermal coefficients of moulding material, i.e. the coefficient of temperature equalisation a2, known also as the temperature diffusivity, and the heat accumulation coefficient b2, which characterises the ability of moulding material to draw away the heat from a casting. The method consists in experimental determining the temperature field within the mould during the processes of pouring, solidification and cooling of the casting. The performed measurements allow for convenient and exact calculations of the sought-after coefficients. Examinations were performed for the oil bonded moulding sand of trade name OBB SAND ‘E’. The experiment showed that the obtained value of b2 coefficient differs from the value calculated on the basis of theoretical considerations available in publications. Therefore it can be stated that theoretical calculations of the heat accumulation coefficient are thus far not sufficient and not quite reliable, so that these calculations should be verified experimentally.

Organic binders applied in foundry plants based on synthetic resins, from the one side influence obtaining the required technological properties by the moulding sand and – in consequence – obtaining good quality castings, and on the other side are the source of volatile organic compounds (VOC). Together with synthetic resins their hardeners, which although added in very small amounts emit during their thermal decomposition substances negatively influencing the natural environment, are also used. Both, resins and hardeners only at the influence of high temperatures accompanying moulds pouring with liquid metal generate harmful volatile organic compounds including compounds from the BTEX group. Investigations of the temperature influence on the kind and amount of organic compounds formed during the thermal decomposition of selected binders and hardeners and their mixtures allow to determine temperature ranges the most favourable for emitting harmful substances as well as to compare their emission from the selected materials. The aim of this study was the determination the temperature influence on formation substances from the BTEX group, during thermal decomposition of the selected binder, its hardener and their mixture. The BTEX group emission constitutes one of the basic criteria in assessing the harmfulness of materials applied for moulding and core sands and it can undergo changes in dependence of the applied system resin-hardener. Investigations were carried out on the specially developed system for the thermal decomposition of organic substances in the temperature range: 5000 C – 13000 C, at the laboratory scale. The investigations subject was the furan resin, its hardener and hardened furan resin. The assessment of the emission degree of the BTEX group in dependence of the system subjected to the temperature influence was performed, within the studies. The temperature range, in which maximal amounts of benzene, toluene, ethylbenzene and xylenes were emitted from tested materials – was defined. The qualitative and quantitative analysis of the BTEX group were carried out with using the gas chromatography technique coupled with the mass spectrometry (GC/MS).

Substituting of ethyl silicate with ecologic sols of colloidal silica in the investment casting technology, resulting from the increased demands concerning environmental protection, caused the prolongation of production cycle for precision castings produced in multi-layer thin-walled ceramic shell moulds. Modification of Sizol 030 binder with benzoyl peroxide, proposed in the paper, was aimed at restriction of time needed for realization of a single layer of the shell mould, and by the same, of such a mould as a whole. Examination of kinetics of the drying process were held for the layers made of prepared moulding material and the influence of binder modification on the mould curing time was determined.

The paper summarises results of measurements of remelting area geometry, thermal efficiency and melting efficiency characterising the surface remelting process applied to castings of MAR-M-509 cobalt alloy. The remelting process was carried out with the use of GTAW (Gas Tungsten Arc Welding) method in protective atmosphere of helium, at the electric current intensity in the range from 100 A to 300 A, and the electric arc scanning velocity vs in the range from 200 mm/min to 800 mm/min. The effect of current intensity and electric arc scanning velocity on geometrical parameters of remeltings, thermal efficiency, and melting efficiency characterising the remelting process has been determined.

The study presents the results of research aimed at the construction of a model of the relationship between the physical properties of metal and the types of toughening treatment and modifiers used in the modification of BA1044 alloy. Samples of melts were subjected to four variants of the heat treatment and to five types of modification. Studies of the samples consisted in measurements of five physical parameters. Consequently, it was necessary to seek a relationship between the nine input parameters and five output parameters. With this number of the variables and a limited number of samples, searching for the relationships by way of statistical methods was obviously impossible, so it was decided to create an approximate model through the use of fuzzy logic. This study describes the process of creating a model and presents the results of some simulation experiments that confirm the validity of the correct approach.

The purpose of the presented experiment was to develop an effective water glass modifier. In the conducted research, an attempt was made to determine the effect of modifier addition on the wettability of quartz grains, viscosity and cohesion of binder and strength Rm U of the sand mixture. Water glass modification was carried out with, obtained in electrochemical process [1], colloidal suspension of ZnO nanoparticles in methanol (modifier I) or propanol (modifier II), characterised by a constant molar concentration of c = 0.3 M. It was demonstrated that the addition of a colloidal suspension of ZnO nanoparticles in propanol (modifier II) had a significant effect on wettability of quartz grains improvement without the accompanying increase in binder viscosity. Testing the mechanical properties Rm U of sand mixtures containing modified binder (modifier II) hardened at ambient conditions showed an approximately 28% increase in strength compared with the Rm U of the sand bonded with an unmodified binder.

High-vanadium cast iron is the white cast iron in which the regular fibrous γ + VC eutectic with the volume fraction of vanadium carbide amounting to about 20% crystallises. This paper presents the results of studies on high-vanadium cast iron subjected to the inoculation treatment with magnesium master alloy. The aim of this operation is to change the morphology of the crystallising VC carbides from the fibrous shape into a spheroidal one. The study also examines the effect of the amount of the introduced inoculant on changes in the morphology of the crystallising VC carbides. To achieve the goals once set, metallographic studies were performed on high-vanadium cast iron of eutectic composition in base state and after the introduction of a variable content of the inoculant. The introduction of magnesium-based master alloy resulted in the expected changes of microstructure. The most beneficial effect was obtained with the introduction of 1.5% of magnesium master alloy, since nearly half of the crystallised vanadium carbides have acquired a spheroidal shape.