Archives of Foundry Engineering

The production of thin-walled castings with wall thickness in the range of 1.5 to 3 mm and below requires the development of insulation

moulding sands and/or core materials. The test has been taken to develop these kind of materials. The study included a description of their

thermophysical properties. Authors described problems related to the heat flow in the casting-mould system, i.e. mathematically described

the main dependence of heat give-up during crystallization of the casting. The influence of the content of polyglicol on the thermophysical

properties of the mould with gypsum and cement binder was examined. Using the ATD method determined were the increments ΔT1 and

ΔT2 describing the temperature changes in the mould during crystallization of hypoeutectic alloy of AlSi6 and the temperature difference

between casting material and mould during the crystallization. In the considered range of technological parameters a description of the

heat flow kinetics was given.

Modern techniques of castings production, including moulding sands production, require a strict technological regime and high quality

materials. In the case of self-hardening moulding sands with synthetic binders those requirements apply mainly to sand, which adds to

more than 98% of the whole moulding sand mixture. The factors that affect the quality of the moulding sands are both chemical (SiO2

,

Fe2O3 and carbonates content) and physical. Among these factors somewhat less attention is paid to the granulometric composition of the

sands. As a part of this study, the effect of sand quality on bending strength Rgu

and thermal deformation of self-hardening moulding sands

with furfural and alkyd resin was assessed. Moulding sands with furfural resin are known [1] to be the most susceptible to the sand quality.

A negative effect on its properties has, among others, high content of clay binder and so-called subgrains (fraction smaller than 0,1mm),

which can lead to neutralization of acidic hardeners (in the case of moulding sands with furfuryl resin) and also increase the specific

surface, what forces greater amount of binding agents. The research used 5 different quartz sands originating from different sources and

characterized with different grain composition and different clay binder content.

Grey cast iron belongs to materials for casting production, which have wide application for different industry branches. Wide spectrum of

properties of these materials is given by the structure of base metal matrix, which can be influenced with heat treatment. Processes of

annealing can be applied for grey cast iron without problems. During heat treatment processes, where higher cooling rates are used, the

thermal and structural strains become important. Usage and conditions of such heat treatment for grey cast iron castings of common

production are the subject of evaluation of this article.

The results of research on stereological parameters of carbides in modified hypoeutectic chromium cast iron were shown in the paper. The

effect of distance the casting heat centre of casting to the carbide phase morphology was examined. The samples for metallographic

examination were taken from various locations of the model casting prepared in a special tester. This model casting was designed to

simulate the solidification of heavy castings. Using the proposed methodology the relation of the distance from the model mould and the

size, perimeter, length, width and the shape factor of carbides was examined. During the analysis, the values of stereological parameters of

carbides changed on various sections of the model casting.

The paper describes existing requirements for tool materials. In the light of experience with these supplied materials, we have

demonstrated their considerable influence on the life of molds for die casting technology. From this research came the evaluation

methodology of these tool materials which has been used for directing the development of a new material. Based on the new regulation of

the chemical composition a sample was casted and forged after that. Then was determined the process of heat treatment and from a block

of this material a mold insert was produced. This insert is now being tested in production.

A number of technologies is developed that substitute simple metal cores in the high-pressure casting technology. Soluble cores, namely

on the salt basis, represent the highest prospect. The contribution gives the results of the production of salt cores by high-pressure

squeezing and shooting with using a binder. Special attention is paid to the shape of NaCl salt crystals with additives and the influence on

strength properties of cores. A technology of bonding the salt cores is developing. Salinity of circulating water is studied and it is checked

with the aid of electrical conductance.

The results of the modification of austenitic matrix in cast high-manganese steel containing 11÷19% Mn with additions of Cr, Ni and Ti

were discussed. The introduction of carbide-forming alloying elements to this cast steel leads to the formation in matrix of stable complex

carbide phases, which effectively increase the abrasive wear resistance in a mixture of SiC and water. The starting material used in tests

was a cast Hadfield steel containing 11% Mn and 1.34% C. The results presented in the article show significant improvement in abrasive

wear resistance and hardness owing to the structure modification with additions of Cr and Ti.

The problem of materials selection in terms of their mechanical properties during the design of new products is a key issue of design. The

complexity of this process is mainly due to a multitude of variants in the previously produced materials and the possibility of their further

processing improving the properties. In everyday practice, the problem is solved basing on expert or designer knowledge. The paper is the

proposition of a solution using computer-aided analysis of material experimental data, which may be acquired from external data sources.

In both cases, taking into account the rapid growth of data, additional tools become increasingly important, mainly those which offer

support for adding, viewing, and simple comparison of different experiments. In this paper, the use of formal knowledge representation in

the form of an ontology is proposed as a bridge between physical repositories of data in the form of files and user queries, which are

usually formulated in natural language. The number and the sophisticated internal structure of attributes or parameters that could be the

criteria of the search for the user are an important issue in the traditional data search tools. Ontology, as a formal representation of

knowledge, enables taking into account the known relationships between concepts in the field of cast iron, materials used and processing

techniques. This allows the user to receive support by searching the results of experiments that relate to a specific material or processing

treatment. Automatic presentation of the results which relate to similar materials or similar processing treatments is also possible, which

should make the conducted analysis of the selection of materials or processing treatments more comprehensive by including a wider range

of possible solutions.

The article presents the method to assess the diffusion coefficient D in the sub-layer of intermetallic phases formed during hot-dip

galvanizing “Armco” iron and ductile cast iron EN-GJS-500-7. Hot-dip galvanizing is one of the most popular forms of long-term

protection of Fe-C alloys against corrosion. The process for producing a protective layer of sufficient quality is closely related to diffusion

of atoms of zinc and iron. The simulation consist in performed a hot-dip galvanizing in laboratory condition above Fe-C alloys, in the

Department of Engineering of Cast Alloys and Composites. Galvanizing time ranged from 15 to 300 seconds. Then metallographic

specimens were prepared, intermetallic layers were measured and diffusion coefficient (D) were calculated. It was found that the diffusion

coefficient obtained during hot-dip galvanizing “Armco” iron and zinc is about two orders of magnitude less than the coefficient obtained

on ductile cast iron EN-GJS-500-7.

The paper presents results of measuring thermal conductivity and heat capacity of bentonite foundry sand in temperature range ambient –

900 OC. 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 water vaporization strongly influences thermal conductivity of the moulding sand in the first period of the mould heating by

the poured casting.

The paper presents results of measuring attenuation coefficient of the Al-20 wt.% Zn alloy (AlZn20) inoculated with different grain

refiners. During experiments the melted alloys were doped with Al-Ti3-C0.15 refining master alloy. Basing on measurements performed

by Krautkramer USLT2000 device with 1MHz ultrasound wave frequency it was stated that grain refinement reduces the attenuation

coefficient by about 20-25%. However, the examined alloys can be still classified as the high-damping ones of attenuation greater than 150

dB/m.

Metallic foams are materials of which the research is still on-going, with the broad applicability in many different areas (e.g. automotive

industry, building industry, medicine, etc.). These metallic materials have specific properties, such as large rigidity at low density, high

thermal conductivity, capability to absorb energy, etc. The work is focused on the preparation of these materials using conventional casting

technology (infiltration method), which ensures rapid and economically feasible method for production of shaped components. In the

experimental part we studied conditions of casting of metallic foams with open pores and irregular cell structure made of ferrous and nonferrous

alloys by use of various types of filler material (precursors).

Currently there is a constant development in the field of aluminium alloys engineering. This results from, i.a., better understanding of the

mechanisms that direct strengthening of these alloys and the role of microalloying. Now it is microalloying in aluminum alloys that is

receiving a lot of attention. It affects substantially the macro- and microstructure and kinetics of phase transformation influencing the

properties during production and its exploitation. 7xxx series aluminum alloys, based on the Al-Zn-Mg-Cu system, are high-strength

alloys, moreover, the presence of Zr and Sr further increases their strength and improves resistance to cracking.

This study aims to present the changes of the properties, depending on the alloy chemical composition and the macro- and microstructure.

Therefore, the characteristics in the field of hardness, tensile strength, yield strength and elongation are shown on selected examples.

Observations were made on ingot samples obtained by semi-continuous casting, in the homogenized state.

Samples were prepared from aluminum alloys in accordance with PN-EN 573-3: 2013. The advantage of Al-Zn-Mg-Cu alloys are

undoubtedly good strength, Light-weight and resistance to corrosion. As widening of the already published studies it is sought to

demonstrate the repeatability of the physical parameters in the whole volume of the sample.

Presented are results of a preliminary research on determining a possibility to use microwave radiation for drying casting protective

coatings applied on patterns used in the lost foam technology. Taken were measurements of permittivity εr and loss factor tgδ at 2.45 GHz,

as well as attempts were made of microwave drying of a protective coating based on aluminium silicates, applied on shapes of foamed

polystyrene and rigid polymeric foam. Time and results of microwave drying were compared with the results obtained by drying at 50 °C

by the traditional method commonly used for removing water from protective coatings. Analysis of the obtained drying kinetics curves

demonstrated that selection of proper operation parameters of microwave equipment permits the drying time to be significantly shortened.

Depending on kind of the pattern material, drying process of a protective coating runs in a different way, resulting in obtaining different

quality of the dried coating.

The paper deals with problems related to application of aluminum-silicon alloys for combustion engine cylinder liners

Elaborated shapes of many car components are the reason for which the use of casting techniques to fabricate them is a solution wellfounded

from the economical point of view. Currently applicable regulatory requirements concerning emissions of exhaust fumes force the

carmakers to reduce the overall weight of their products, as this is a basic precondition for reducing fuel consumption. As a result, newly

launched car models contain a continuously increasing share of thin-walled castings made of materials which ensure a satisfactory level of

service properties. At the same time, developing new technological processes allowing to extend the service life of individual components

by means of surface improving becomes more and more important.

The paper presents an analysis of factors affecting the wear of cylinder liners. The effect of the graphite precipitation morphology on the

cylinder liner wear mechanism is presented. Materials used to cast cylinder liners mounted in a number of engines have been examined for

their conformity with requirements set out in applicable Polish industrial standard. A casting for a prototype cylinder liner has been made

with a microstructure guaranteeing good service properties of the part.

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 work deals with technology Patternless process that combines 3 manufacturing process mold by using rapid prototyping technology,

conventional sand formation and 3D milling. It's unconventional technology that has been developed to produce large-sized and heavyduty

castings weighing up to several tons. It is used mainly in prototype and small batch production, because eliminating production of

models. The work deals with the production of blocks for making molds of gypsum and gypsum drying process technology Thermomold.

Into blocks, where were made cavities by milling were casted test castings from AlSi10MgMn alloy by gravity casting. At machining of

the mold cavity was varied feed rate of tool of cemented carbide. Evaluated was the surface roughness of test castings, that was to 5

micrometers with feed from 900 to 1300 mm/min. The dimensional accuracy of castings was high at feed rate of 1000 and 1500 mm/min

did not exceed 0.025 mm.

This paper deals with influence on segregation of iron based phases on the secondary alloy AlSi7Mg0.3 microstructure by nickel. Iron is

the most common and harmful impurity in aluminum casting alloys and has long been associated with an increase of casting defects. In

generally, iron is associated with the formation of Fe-rich intermetallic phases. It is impossible to remove iron from melt by standard

operations. Some elements eliminates iron by changing iron intermetallic phase morphology, decreasing its extent and by improving alloy

properties. Realization of experiments and results of analysis show new view on solubility of iron based phases during melt preparation

with higher iron content and influence of nickel as iron corrector of iron based phases.

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.

Deoxidation of steel with carbon under reduced pressure is often used for increasing the steel purity. Suitable units for this purpose in

foundries are vacuum induction furnaces. Possibilities of increasing the steel purity by deoxidation with carbon in the vacuum induction

furnace were studied for the steel for the petrochemistry of specific composition 25Cr/35Ni. The charge composed of the return material

only was melted in the air. During melting the charge oxidized and the oxidizing slag formed. Chemical composition of steel, morphology,

chemical composition of inclusions in the steel and chemical composition of slag after vacuuming were studied on the basis of samples

taken before and after vacuuming. Temperature and oxygen activity were measured before and after vacuuming. Globular inclusions with

dominant content of silicon and manganese were observed in steel before and after vacuuming. Contents of total oxygen in steel didn’t

change significantly during vacuuming. On the basis of composition of inclusions and measured oxygen activity the activity of Cr2O3

in

inclusions was calculated. A slag sample was taken after vacuuming and equilibrium oxygen activity in steel with regard to the Cr2O3

content in the slag was estimated from the slag composition. Equilibrium oxygen activity in relation to the Cr2O3 content in the slag was

higher than equilibrium activity measured in the steel. For this reason it is not possible, under the studied conditions, to decrease oxygen

content in steel during vacuuming.