In the paper, an attempt is made to explain the previously observed increased effectiveness of utilising hydrated sodium water-glass grade

137 after hardening moulding sands with selected physical methods. In the modified process of preparing sandmixes, during stirring

components, water as a wetting additive was introduced to the sand-binder system. Presented are examination results of influence of faster

microwave heating and slower traditional drying of the so-prepared moulding sands on their tensile and bending strength, calculated per

weight fraction of the binder. The measurement results were confronted with SEM observations of linking bridges and with chemical

analyses of grain surfaces of high-silica base. On the grounds of comprehensive evaluation of hardened moulding sands, positive effects

were found of the applied physical process of binder dehydration and presence of the wetting additive. It was observed that introduction of

this additive during stirring, before adding the binder, improves flowing the binder to the places where durable linking bridges are created.

It was also found that the applied methods of hardening by dehydration enable creation of very durable linking bridges, strongly connected

with the sand base, which results in damages of high-silica grain surfaces, when the bridges are destroyed.

Presented are results of a research on the possibility of using artificial neural networks for forecasting mechanical and technological

parameters of moulding sands containing water-glass, hardened in the innovative microwave heating process. Trial predictions were

confronted with experimental results of examining sandmixes prepared on the base of high-silica sand, containing various grades of

sodium water-glass and additions of a wetting agent. It was found on the grounds of obtained values of tensile strength and permeability

that, with use of artificial neural networks, it is possible complex forecasting mechanical and technological properties of these materials

after microwave heating and the obtained data will be used in further research works on application of modern analytic methods for

designing production technology of high-quality casting cores and moulds.

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.

In the paper, an attempt was made to evaluate the effect of preliminary wetting of high-silica base during preparation of moulding sands

containing a selected grade of sodium water-glass, designed for hardening by traditional drying or by electromagnetic microwaves at 2.45

GHz. In the research, some water was dosed during stirring the sandmix before adding 1.5 wt% of the binder that was unmodified sodium

water-glass grade 137, characterised by high molar module within 3.2 to 3.4. Scope of the examinations included determining the effect of

wetting the base on mechanical parameters like compression, bending and tensile strength, as well as on technological parameters like

permeability, abrasion resistance and apparent density. The research revealed a significant positive effect of adding water to wet surfaces

of high-silica base grains on mechanical properties and quality of moulding sands hardened by physical methods, in particular by

microwave heating

In the paper, a research on effects of baking temperature on chromite sand base of moulding sands bonded with sodium silicate is

presented. Pure chromite sand and its chromite-based moulding sand prepared with use of sodium silicate were subjected to heating within

100 to 1200 °C. After cooling-down, changes of base grains under thermal action were determined. Chromite moulding sand was prepared

with use of 0.5 wt% of domestic made, unmodified sodium silicate (water-glass) grade 145. After baking at elevated temperatures, creation

of rough layer was observed on grain surfaces, of both pure chromite sand and that used as base of a moulding sand. Changes of sand

grains were evaluated by scanning microscopy and EDS analyses. It was found that changes on grain surfaces are of laminar nature. The

observed layer is composed of iron oxide (II) that is one of main structural components of chromite sand. In order to identify changes in

internal structure of chromite sand grains, polished sections were prepared of moulding sand hardened with microwaves and baked at

elevated temperatures. Microscopic observations revealed changes in grains structure in form of characteristically crystallised acicular

particles with limited magnesium content, intersecting at various angles. EDS analysis showed that these particles are composed mostly of

chromium oxide (III) and iron oxide (II). The temperature above that the a.m. changes are observed in both chromite-based moulding sand

and in pure chromite sand. The observed phenomena were linked with hardness values and mass of this sand.

In the paper, a research on effects of baking temperature on chromite sand base of moulding sands bonded with sodium silicate is

presented. Pure chromite sand and its chromite-based moulding sand prepared with use of sodium silicate were subjected to heating within

100 to 1200 °C. After cooling-down, changes of base grains under thermal action were determined. Chromite moulding sand was prepared

with use of 0.5 wt% of domestic made, unmodified sodium silicate (water-glass) grade 145. After baking at elevated temperatures, creation

of rough layer was observed on grain surfaces, of both pure chromite sand and that used as base of a moulding sand. Changes of sand

grains were evaluated by scanning microscopy and EDS analyses. It was found that changes on grain surfaces are of laminar nature. The

observed layer is composed of iron oxide (II) that is one of main structural components of chromite sand. In order to identify changes in

internal structure of chromite sand grains, polished sections were prepared of moulding sand hardened with microwaves and baked at

elevated temperatures. Microscopic observations revealed changes in grains structure in form of characteristically crystallised acicular

particles with limited magnesium content, intersecting at various angles. EDS analysis showed that these particles are composed mostly of

chromium oxide (III) and iron oxide (II). The temperature above that the a.m. changes are observed in both chromite-based moulding sand

and in pure chromite sand. The observed phenomena were linked with hardness values and mass of this sand.

The paper presents the results of preliminary research on the application of olivine moulding sands with hydrated sodium silicate containing 1.5 % wt. of binder to perform ecological casting cores in hot-box technology using a semi-automatic core shooter. The following parameters were used in the process of core shooting: initial shot pressure of 6 bar, shot time 3 s, the temperature of the corebox: 200, 250 and 300 °C and the core curing time: 30, 60, 90, 120 and 150 s. The matrix of the moulding mixture was olivine sand, and the binder of the sandmix was commercial, unmodified hydrated sodium silicate with molar module SiO2/Na2O of 2.5. In one shot of the automatic core-shooter were formed three longitudinal specimens (cores) with a dimensions 22.2×22.2×180 mm. The samples obtained in this way were subjected to the assessment of the influence of the shooting parameters, i.e. shooting time, temperature and curing time in core-box, using the following criteria: core box fill rate, mechanical strength to bending Rg U, apparent density, compaction degree and susceptibility to friability of sand grains after hardening. The results of trials on the use of olivine moulding sands with hydrated sodium silicate (olivine SSBS) in the process of core shooting made it possible to determine the conditions for further research on the improvement of inorganic hot-box process technology aimed at: reduction of the heating temperature and the curing time. It was found that correlation between the parameters of the shooting process and the bending strength of olivine moulding sands with sodium silicate is observed.