Archives of Foundry Engineering

The paper undertakes an important topic of evaluation of effectiveness of SCADA (Supervisory Control and Data Acquisition) systems,

used for monitoring and control of selected processing parameters of classic green sands used in foundry. Main focus was put on process

studies of properties of so-called 1st generation molding sands in the respect of their preparation process. Possible methods of control of

this processing are presented, with consideration of application of fresh raw materials, return sand (regenerate) and water. The studies

conducted in one of European foundries were aimed at pointing out how much application of new, automated plant of sand processing

incorporating the SCADA systems allows stabilizing results of measurement of selected sand parameters after its mixing. The studies

concerned two comparative periods of time, before an implementation of the automated devices for green sands processing (ASMS -

Automatic Sand Measurement System and MCM – Main Control Module) and after the implementation. Results of measurement of

selected sand properties after implementation of the ASMS were also evaluated and compared with testing studies conducted periodically

in laboratory.

In this study, modification of the AZ91 magnesium alloy surface layer with a CO2 continuous wave operation laser has been taken on. The

extent and character of structural changes generated in the surface layer of the material was being assessed on the basis of both macro- and

microscopy investigations, and the EDX analysis. Considerable changes in the structure of the AZ91 alloy surface layer and the

morphology of phases have been found. The remelting processing was accompanied by a strong refinement of the structure and a more

uniform distribution of individual phases. The conducted investigations showed that the remelting zone dimensions are a result of the

process parameters, and that they can be controlled by an appropriate combination of basic remelting parameters, i.e. the laser power, the

distance from the sample surface, and the scanning rate. The investigations and the obtained results revealed the possibility of an effective

modification of the AZ91 magnesium alloy surface layer in the process of remelting carried out with a CO2 laser beam.

The main reason of a cavitational destruction is the mechanical action of cavitation pulses onto the material’s surface. The course

of cavitation destruction process is very complex and depends on the physicochemical and structural features of a material. A resistance

to cavitation destruction of the material increases with the increase of its mechanical strength, fatigue resistance as well as hardness.

Nevertheless, the effect of structural features on the material’s cavitational resistance has been not fully clarified. In the present paper,

the cavitation destruction of ZnAl4 as cast alloy was investigated on three laboratory stands: vibration, jet-impact and flow stands.

The destruction mechanism of ZnAl4 as cast alloy subjected to cavitational erosion using various laboratory stands is shown in the present

paper.

The paper presents the results of investigations of the growth of protective coating on the surface of ductile iron casting during the hot-dip

galvanizing treatment. Ductile iron of the EN-GJS-600-3 grade was melted and two moulds made by different technologies were poured to

obtain castings with different surface roughness parameters. After the determination of surface roughness, the hot-dip galvanizing

treatment was carried out. Based on the results of investigations, the effect of casting surface roughness on the kinetics of the zinc coating

growth was evaluated. It was found that surface roughness exerts an important effect on the thickness of produced zinc coating

The paper presents results of measuring heat diffusivity and thermal conductivity coefficients of used green foundry sand in temperature

range ambient – 600 o

C. During the experiments a technical purity Cu plate was cast into the green-sand moulds. Basing on measurements

of the mould temperature field during the solidification of the casting, the temperature relationships of the measured properties were

evaluated. It was confirmed that the obtained relationships are complex and that water vaporization strongly influences thermal

conductivity of the moulding sand in the first period of the mould heating by the poured and solidified casting

Cu–4.7 wt. % Sn alloy wire with Ø10 mm was prepared by two-phase zone continuous casting technology, and the temperature field, heat

and fluid flow were investigated by the numerical simulated method. As the melting temperature, mold temperature, continuous casting

speed and cooling water temperature is 1200 °C, 1040 °C, 20 mm/min and 18 °C, respectively, the alloy temperature in the mold is in the

range of 720 °C–1081 °C, and the solid/liquid interface is in the mold. In the center of the mold, the heat flow direction is vertically

downward. At the upper wall of the mold, the heat flow direction is obliquely downward and deflects toward the mold, and at the lower

wall of the mold, the heat flow deflects toward the alloy. There is a complex circular flow in the mold. Liquid alloy flows downward along

the wall of the mold and flows upward in the center.

Thermal processes in domain of thin metal film subjected to a strong laser pulse are discussed. The heating of domain considered causes

the melting and next (after the end of beam impact) the resolidification of metal superficial layer. The laser action (a time dependent belltype

function) is taken into account by the introduction of internal heat source in the energy equation describing the heat transfer in domain

of metal film. Taking into account the extremely short duration, extreme temperature gradients and very small geometrical dimensions of

the domain considered, the mathematical model of the process is based on the dual phase lag equation supplemented by the suitable

boundary-initial conditions. To model the phase transitions the artificial mushy zone is introduced. At the stage of numerical modeling the

Control Volume Method is used. The examples of computations are also presented.

The paper presents the influence of modification with phosphorus (CuP10) on the tribological properties of the alloy AlSi17Cu5Mg coupled

abrasively with cast-iron EN GJL-350. Tests of coefficient of friction and wear of mass were conducted on tribological tester T-01. An

important aspect in the assessment of the tribological properties is the analysis of initial material microstructure in reference to silumin which

underwent modification with phosphorus. It was found that the difference in structure of tested materials, mainly sizes of primary silicon

crystals significantly influences the tribological properties whereas the speed change of the friction knot does not have such big influence.

A new Computer-Aided Design approach is introduced for design of steel castings taking into account the feeding ability in sand moulds.

This approach uses the geometrical modeling by a CAD-program, in which the modul “Castdesigner” is implemented, which includes the

feeding models of steel castings. Furthermore, the feeding ability is guaranteed immediately during the design by an interactive geometry

change of the casting cross section, so that a directional feeding of the solidifying casting from the installed risers is assured.

The article presents the analysis of properties of the high-strength AlZnMgCu (abbr AlZn) aluminium alloy and estimates possibilities of

its application for responsible structures with reduced weight as an alternative to iron alloy castings. The aim of the conducted studies was

to develop and select the best heat treatment regime for a 7xx casting alloy based on high-strength materials for plastic working from the

7xxx series. For analysis, wrought AlZnMgCu alloy (7075) was selected. Its potential of the estimated as-cast mechanical properties

indicates a broad spectrum of possible applications for automotive parts and in the armaments industry. The resulting tensile and fatigue

properties support the thesis adopted, while the design works further confirm these assumptions.

US A356 and US 413 cast aluminium alloys shrinkage characteristic have been discussed in the present study. Specific volume reduction

leads to shrinkage in castings and it can be envisaged as a casting defect. Finite difference based casting process simulation software has

been used to study the shrinkage characteristic and it is quantified using mathematical formulae. The three dimensional model of the

shrinkage defect has been constructed using CAD application software. Shrinkage characteristic has also been quantified through

experimental validation studies and compared well with casting process simulation. Shrinkage characteristic study and control is essential

for producing defect free castings. Influence of casting shape on the shrinkage characteristic has been studied in this paper.

The investigation results of the reclamation of spent moulding sands with furfuryl resin are presented in this paper. The reclamation

process was performed in the secondary reclamation chamber of the REGMAS 1.5 vibratory reclaimer. 70 kg portions of moulding sands,

previously subjected to the primary reclamation and dedusting, were used. The secondary reclamation was performed in two stages: the

first consisted of determining the reclaimer intensity at various reclamation times (5 min, 10 min and 15 min) and various electrovibrator

frequencies (40 Hz, 50 Hz and 60 Hz), the second consisted of determining the influence of additional crushing elements on the intensity

of processes.

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, 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.

The size and complexity of decision problems in production systems and their impact on the economic results of companies make it

necessary to develop new methods of solving these problems. One of the latest methods of decision support is business rules management.

This approach can be used for the quantitative and qualitative decision, among them to production management. Our study has shown that

the concept of business rules BR can play at most a supporting role in manufacturing management, but alone cannot form a complete

solution for production management in foundries.

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.

The suspension of copper droplets in the slag is considered. The copper/slug suspension is delivered as the product from the direct-toblister

process which is applied in the KGHM – Polska Miedź (Polish Copper) S.A. factory. The droplets / slag suspension was treated by

a special set of reagents (patented by the authors) to improve the coagulation process. On the other hand, the observations are made to

estimate if the melting / reduction process in the furnace is sufficiently effective to avoid a remaining of carbon in the copper droplets.

The coagulation process was carried out in the crucible (laboratory scale). However, conditions imposed to the coagulation / solidification

process in the laboratory scale were to some extent similar to those applied usually in the industry when the suspension is subjected to the

analogous treatment in the electric arc-furnace. Some suggestions are formulated how to improve the industrial direct-to-blister process.

A numerical model of binary alloy crystallization, based on the cellular automaton technique, is presented. The model allows to follow the

crystallization front movement and to generate the images of evolution of the dendritic structures during the solidification of a binary

alloy. The mathematic description of the model takes into account the proceeding thermal, diffusive, and surface phenomena. There are

presented the results of numerical simulations concerning the multi-dendritic growth of solid phase along with the accompanying changes

in the alloying element concentration field during the solidification of Al + 5% wt. Mg alloy. The model structure of the solidified casting

was achieved and compared with the actual structure of a die casting. The dendrite interaction was studied with respect to its influence on

the generation and growth of the primary and secondary dendrite arms and on the evolution of solute segregation both in the liquid and in

the solid state during the crystallization of the examined alloy. The morphology of a single, free-growing dendritic crystal was also

modelled. The performed investigations and analyses allowed to state e.g. that the developed numerical model correctly describes the

actual evolution of the dendritic structure under the non-equilibrium conditions and provides for obtaining the qualitatively correct results

of simulation of the crystallization process.

The furan resin offers advantages such as high intensity, low viscosity, good humidity resistance and is suitable for cast different casting

alloys: steel, cast iron and non-ferrous metal casting. For hardening furan resins are used different hardeners (acid catalysts). The acid

catalysts have significant effects on the properties of the cured binder (e,g. binding strength and thermal stability) [1 - 3]. Investigations of

the gases emission in the test foundry plant were performed according to the original method developed in the Faculty of Foundry

Engineering, AGH UST. The analysis is carried out by the gas chromatography method with the application of the flame-ionising detector

(FID) (TRACE GC Ultra THERMO SCIENTIFIC).

Al-enriched layer was formed on a magnesium substrate with use of casting. The magnesium melt was cast into a steel mould with an

aluminium insert placed inside. Different conditions of the casting process were applied. The reaction between the molten magnesium and

the aluminium piece during casting led to the formation of an Al-enriched surface layer on the magnesium substrate. The thickness of the

layer was dependent on the casting conditions. In all fabricated layers the following phases were detected: a solid solution of Mg in Al,

Al3Mg2, Mg17Al12 and a solid solution of Mg in Al. When the temperature of the melt and the mould was lower (variant 1 – 670o

C and 310 o

; variant 2 – 680o

C and 310o

C, respectively) the unreacted thin layer of aluminium was observed in the outer zone. Applying higher

temperatures of the melt (685o

C) and the mould (325o

C) resulted in deep penetration of aluminium into the magnesium substrate. Areas

enriched in aluminium were locally observed. The Al-enriched layers composed mainly of Mg-Al intermetallic phases have hardness from

187-256 HV0.1.

Paper presents the results of studies on primary crystallization and wear resistance of high chromium cast iron inoculated with

ferrotitanium intended for work in abrasive conditions. Primary crystallization was examined with use of TDA method, wear tests of the

samples were conducted using the modified pin-on-disk method.

Directional solidification of the Fe - 4,3 wt % C alloy was performed with the pulling rate equal to v=83 μm/s. Sample was frozen during

solidification to reveal the shape of the solid/liquid interface. Structures eutectic pyramid and spherolitic eutectic were observed. The

solidification front of ledeburite eutectic was revealed. The leading phase was identified and defined.

Horizontal centrifugal casting is an effective method for the production of hollow metal with good mechanical properties, low defect, cast

to size and relatively cheap. The ability of a metal to satisfy the above requirements highly depends on its microstructure. In this study, the

relationship between microstructural parameters such as grain size and the amount of phases with bulk hardness of SnCu4Pb3 is concerned

in three areas of the product. Consequently, to achieve the desired hardness of the product in a particular area, the interaction of two

factors of the microstructure including, grain size and particles amount of the hard intermetallic compositions (Cu6Sn5) should be noted.