Archives of Foundry Engineering

The article describes the optimization of the melting brass. Brasses, as one of the most popular alloys of copper, deserve special attention

in the context of the processes of melting, which in turn would provide not only products of better quality, but also reduce the cost of their

production or refining. For this purpose, several studies carried out deriatographic (DTA) and thermogravimetric (TG) using

derivatograph. The results were confronted with the program SLAG - PROP used to evaluate the physicochemical properties of the

coatings extraction. Based on the survey and analysis of the program can identify the most favorable physico - chemical properties, which

should be carried out treatments. This allows for slag mixtures referred configurations oxide matrix containing specific stimulators of the

reaction. Conducted empirical studies indicate a convergence of the areas proposed by the application. It should also be noted that the

program also indicates additional areas in which to carry out these processes would get even better, to optimize the melting process, the

results.

Air abrasion process is used for cleaning casting surface of prosthetic components, and to prepare the surface of these elements for the

application of veneering items. Its side effect, however, is that abrasive particles are embedded in the treated surface, which can be up to

30% of the surface and it constitutes the side effect of this procedure. Such a significant participation of foreign material can not be

indifferent to the properties of the surface. Embedded particles can be the place of stress concentration causing cracking of ceramics, and

may deteriorate corrosion resistance by forming corrosive microlinks. In the latter cases, it would be advisable to remove elements

embedded into the surface. The simplest method is chemical etching or electrochemical one. Nevertheless, these procedures should not

significantly change the parameters of the surface. Among many possible reagents only a few fulfills all the above conditions. In addition,

processing should not impair corrosion resistance of titanium, which is one of the most important factors determining its use as a prosthetic

restoration in the mouth. The study presented results of corrosion resistance of titanium used to make prosthetic components by means of

casting method, which were subjected to chemical processing designed to remove the embedded abrasive particles. The aim of the study

was to investigate whether etching with selected reagents affects the corrosion resistance of titanium castings. For etching the following

reagents were used: 30% HNO3 + 3% HF + H2O, HNO3+ HF+ glycerol (1:2:3), 4% HF in H2O2, 4% HF in H2O, with a control

sandblasted sample, not subjected to etching. Tests demonstrated that the etching affected corrosion properties of test samples, in each case

the reduction of the corrosion potential occurred - possibly due to the removal of particles of Al2O3 from the surface and activation of the

surface. None of the samples underwent pitting corrosion as a result of polarization to 9 V. Values of the polarization resistance, and

potentiodynamic characteristics indicated that the best corrosion resistance exhibited the samples after etching in a mixture of 4% solution

of HF in H2O2. They showed very good passivation of the surface.

The problem considered in the paper is motivated by production planning in a foundry equipped with the furnace and casting line, which

provides a variety of castings in various grades of cast iron/steel for a large number of customers. The quantity of molten metal does not

exceed the capacity of the furnace, the load is a particular type of metal from which the products are made. The goal is to create the order

of the melted metal loads to prevent delays in delivery of goods to customers. This problem is generally considered as a lot-sizing and

scheduling problem. The paper describes a mathematical programming model that formally defines the optimization problem and its

relaxed version that is based on the conception of rolling-horizon planning

This paper presents a study of the effect of the modification and cooling rate on the grain count α(Al) in the Al-5Cu alloy. Research was

performed on castings with walls thickness between 3 mm and 25 mm. Cooling curves were recorded to determine the cooling rate and the

degree of undercooling at the beginning of solidification. It has been shown that cooling rate increases exponentially as the wall thickness

of casting decreases. Moreover it has been demonstrated that the cooling rate of castings changes within a wide range (21ºC/s - 1ºC/s)

when the wall thickness changes from 3 up to 25 mm. Metallographic examinations revealed primary grains (primary α(Al) grains). The

paper show that the relationship between the grain count and the degree of undercooling (for non-modified and modified alloys) can be

represented by the equation N = Nv = np·exp(-b/ΔTα), based on the Weibull's distribution of the size of nucleation sites.

This research presents comprehensive assessment of the precision castings quality made in the Replicast CS process. The evaluation was

made based on quality of the surface layer, shape errors and the accuracy of the linear dimensions. Studies were carried out on the modern

equipment, among other things a Zeiss Calypso measuring machine and profilometer were used. Obtained results allowed comparing lost

wax process models and Replicast CS process.

Extremely intense development of civilization requires from foundry casting technologies very high quality and not expensive castings. In

the foundries, there are many treatments that allow increasing of the final properties of produced castings such as refining, modification,

heat treatment, etc. One of the methods of increasing the quality of the casting by removing inclusions from the liquid alloy is filtration.

The use of ceramic-carbon foam filters in filtration process is still analysed phenomenon that allows improving the final properties of

castings. A modern method of research, testing and synthesis of innovative chemical compositions allows improving the properties of such

filters. In the paper the evaluation of application properties of developed ceramic-carbon bonded foam filters is presented. The quality of

the foam filters is evaluated by Computer Tomography and foundry trials in pouring of liquid metal in test molds. Additionally computer

simulations were made to visualize the flow characteristics in the foam filter. The analysed filters are the result of the research work of

Foundry Research Institute and the Institute of Ceramics and Building Materials, Refractory Materials Department in Gliwice.

The cast alloys crystallizing in Fe-C-V system are classified as white cast iron, because all the carbon is bound in vanadium carbides. High

vanadium cast iron has a very high abrasion resistance due to hard VC vanadium carbides. However, as opposed to ordinary white cast

iron, this material can be treated using conventional machining tools. This article contains the results of the group of Fe-C-V alloys of

various microstructure which are been tested metallographic, mechanical using an INSTRON machine and machinability with the method

of drilling. The study shows that controlling the proper chemical composition can influence on the type and shape of the crystallized

matrix and vanadium carbides. This makes it possible to obtain a high-vanadium cast iron with very high wear resistance while

maintaining a good workability.

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 article presents results of heat treatment on the high chromium cast iron. The study was carrying out on samples cut from the casting

made from chromium cast iron. Those were hardened at different temperatures, then tempered and soft annealed. The heat treatment was

performed in a laboratory chamber furnace in the Department of Engineering Alloys and Composites at Faculty of Foundry Engineering

AGH. At each stage of the heat treatment the hardness was measured by Vickers and Rockwell methods, and the microscope images were

done. Additionally based on images from the optical microscope the microstructure was assessed. Based on these results, the effect of

hardening, tempering and soft annealing on the microstructure and hardness of high chromium cast iron was studied. Next the effects of

different hardening temperatures on the properties of high chromium cast iron were compared. The study led to systemize the literature

data of the parameters of heat treatment of high chromium cast iron, and optimal conditions for heat treatment was proposed for casts of

similar properties and parameters.

The paper presents the issue of production processes improvement in foundries in the area of finishing treatment of iron casts

manufactured on automated foundry lines with vertical or horizontal mould division. Due to numerous factors which influence

the efficiency of the processes, multi-criterion assessment tools were proposed in order to select the optimal solution for the assumed

criteria. After determining the criteria weight using the Saaty method, a simulation experiment was designed and carried out which

presents possible scenarios of casts finishing treatment operations. Basing on experiment reports from a computer model, particular

solutions were evaluated using the Yager’s method. The evaluation of the experiment results was performed by experts who assessed

different options according to each of the criteria adopted. After the establishment of the total standardized ratings by averaging the scores

given by individual experts, the final decision was generated. Using the presented method, the best solution was chosen from among

the analyzed scenarios.

The presented work deals with the influence of the addition of soft graphite particles on the abrasive wear of composite reinforced with

hard SiC particles. The discussed hybrid composites were produced by stirring the liquid alloy and simultaneous adding the mixture of

particles. The adequately prepared suspension was gravity cast into a metal die. Both the composite castings obtained in this way and the

comparative castings produced of the pure matrix alloy were examined for the abrasive wear behaviour. Photomacrographs of the sliding

surfaces of the examined composites were taken, and also the hardness measurements were carried out. It was found that even a small

addition of Cgr particles influences positively the tribological properties of the examined composite materials, protecting the abraded

surface from the destructive action of silicon carbide particles. The work presents also the results of hardness measurements which confirm

that the composite material hardness increases with an increase in the volume fraction of hard reinforcing particles.

The article presents two modules operating in a hybrid CAPCAST system implemented in the Department of Applied Computer Science

and Modelling, AGH University of Science and Technology, Cracow. These are the modules: CAPCAST-base of producers and

CAPCAST-base of materials. Registered producers may benefit from other modules of the system, the base can also be an independent

source of knowledge about Polish foundries and their production capacity, and can serve as a kind of platform for the implementation of

the basic functions of e-business. The base of materials can also be a source of knowledge about materials, and it allows searching and

filtering the lists of materials in terms of user-selected attributes using a multi-level search engine. This module is integrated with the rest

of the system and can be used by other modules. The system has been developed at the AGH Department of Applied Computer Science

and Modelling in Cracow.

With the increase in wall thickness of the casting of iron-nickel-aluminium-bronze, by the reduction of the cooling rate the size of κII phase

precipitates increases. This process, in the case of complex aluminium bronzes with additions of Cr, Mo and W is increased. Crystallization

of big κII phase, during slow cooling of the casting, reduces the concentration of additives introduced to the bronze matrix and hardness.

Undertaken research to develop technology of thick-walled products (g> 6 mm) of complex aluminium bronzes. Particular attention

was paid to the metallurgy of granules. As a result, a large cooling speed of the alloy, and also high-speed solidification casting a light

weight of the granules allows: to avoid micro-and macrosegregation, decreasing the particle size, increase the dispersion of phases in

multiphase alloys. Depending on the size granules as possible is to provide finished products with a wall thickness greater than 6 mm by

infiltration of liquid alloy of granules (composites). Preliminary studies was conducted using drip method granulate of CuAl10Fe5Ni5

bronze melted in a INDUTHERM-VC 500 D Vacuum Pressure Casting Machine. This bronze is a starting alloy for the preparation of the

complex aluminium bronzes with additions of Cr, Mo, W and C or Si. Optimizations of granulation process was carried out. As the process

control parameters taken a casting temperature t (°C) and the path h (mm) of free-fall of the metal droplets in the surrounding atmosphere

before it is intensively cooled in a container of water. The granulate was subjected to a sieve analysis. For the objective function was

assume maximize of the product of Um*n, the percentage weight "Um" and the quantity of granules 'n' in the mesh fraction. The maximum

value of the ratio obtained for mesh fraction a sieve with a mesh aperture of 6.3 mm. In the intensively cooled granule of bronze was

identified microstructure composed of phases: β and fine bainite (α+β'+β'1) and a small quantity of small precipitates κII phase. Get high

microhardness bronze at the level of 323±27,9 HV0,1.

Paper presents the results of evaluation of heat resistance and specific heat capacity of MAR-M-200, MAR-M-247 and Rene 80 nickel

superalloys. Heat resistance was evaluated using cyclic method. Every cycle included heating in 1100°C for 23 hours and cooling for 1

hour in air. Microstructure of the scale was observed using electron microscope. Specific heat capacity was measured using DSC

calorimeter. It was found that under conditions of cyclically changing temperature alloy MAR-M-247 exhibits highest heat resistance.

Formed oxide scale is heterophasic mixture of alloying elements, under which an internal oxidation zone was present. MAR-M-200 alloy

has higher specific heat capacity compared to MAR-M-247. For tested alloys in the temperature range from 550°C to 800°C precipitation

processes (γ′, γ′′) are probably occurring, resulting in a sudden increase in the observed heat capacity.

Of great importance in the selection of materials for cast structures is keeping a proper balance between the mechanical and plastic properties,

while preserving the relevant casting properties. This study has been devoted to an analysis of the choice and application of highstrength

aluminium-based alloys maintaining sufficient level of casting properties. The high level of tensile strength (Rm > 500 MPa)

matched with satisfactory elongation (A > 3%) is important because materials of this type are used for cast parts operating in the aerospace,

automotive, and military industries. These beneficial relationships between the high tensile strength and toughness are relatively easy to

obtain in the Al-Zn-Mg-Cu alloys subjected to plastic forming and proper heat treatment. In gravity cast products, on the other hand,

whether poured into sand moulds or metal moulds (dies), obtaining this favourable combination of properties poses a number of research

problems (mostly resulting from the alloy chemical composition) as well as technical and technological difficulties.

The paper presents the issue of synthetic cast iron production in the electric induction furnace exclusively on the steel scrap base. Silicon

carbide and synthetic graphite were used as carburizers. The carburizers were introduced with solid charge or added on the liquid metal

surface. The chemical analysis of the produced cast iron, the carburization efficiency and microstructure features were presented in the

paper. It was stated that ferrosilicon can be replaced by silicon carbide during the synthetic cast iron melting process. However, due to its

chemical composition (30% C and 70% Si) which causes significant silicon content in iron increase, the carbon deficit can be partly

compensated by the carburizer introduction. Moreover it was shown that the best carbon and silicon assimilation rate is obtained where the

silicon carbide is being introduced together with solid charge. When it is thrown onto liquid alloy surface the efficiency of the process is

almost two times less and the melting process lasts dozen minutes long. The microstructure of the cast iron produced with the silicon

carbide shows more bulky graphite flakes than inside the microstructure of cast iron produced on the pig iron base.

The paper presents the results of research on the microstructure of GX2CrNiMoCuN25-6-3-3 and GX2CrNiMoCuN25-6-3 cast steels with

a varying carbon content. The cause for undertaking the research were technological problems with hot cracking in bulk castings of duplex

cast steel with a carbon content of approx. 0.06% and with 23% Cr, 8.5% Ni, 3% Mo and 2.4% Cu. The research has shown

a significant effect of increased carbon content on the ferrite and austenite microstructure morphology, while exceeding the carbon content

of 0.06% results in a change of the shape of primary grains from equiaxial to columnar.

One type of spheroidal cast iron, with additions of 0.51% Cu and 0.72% Ni, was subjected to precipitation hardening. Assuming that the

greatest increase in hardness after the shortest time of ageing is facilitated by chemical homogenisation and fragmentation of cast iron

grain matrix, precipitation hardening after pre-normalisation was executed. Hardness (HB), microhardness (HV), qualitative and

quantitative metalographic (LM, SEM) and X-ray structural (XRD) tests were performed. The acquired result of 13.2% increase in

hardness after ca. 5-hour ageing of pre-normalised cast iron confirmed the assumption.

This scientific paper presents the research on influence of austenitizing temperature on kinetics and evolution of the spheroidal plain cast

iron during eutectoid reaction in isothermal conditions. The cast iron has been austenitized in temperatures of 900, 960 or 1020°C. There

were two temperature values of isothermal holding taken into consideration: 760 or 820°C. The order of creation of reaction products and

their morphology have been analyzed. The particular attention has been paid to the initial stage of transformation. The qualitative research

has been executed using the transmission electron microscope (TEM), as well as quantitative research (LM). The influence of austenitizing

temperature has also been determined on transformation kinetics and structural composition. It was found that the increase of austenitizing

temperature is conductive to the initial release of structures by metastable system. A reduction of time was observed of the initial stage of

transformation at temperature close to Ar12 with its simultaneous elongation at temperature close to Ar11, with an increase of austenitizing

temperature. The dependences obtained by the metallographic method confirm the prior results of dilatometric research of eutectoid

reaction.

The work presents the results of the investigations of the effect of the nitrogen (N2) refining time „τraf” and the gas output on the course of

the crystallization process, the microstructure and the gassing degree of silumin 226 used for pressure casting. The refinement of the

examined silumin was performed with the use of a device with a rotating head. The crystallization process was examined by way of

thermal analysis and derivative analysis TDA. The performed examinations showed that the prolongation of the N2 refining time causes

a significant rise of the temperature of the crystallization end of the silumin, „tL”, as well as a decrease of its gassing degree, „Z”. An

increase of the nitrogen output initially causes an increase of the temperature „tL” and a drop of the gassing degree „Z”, which reach their

maximal values with the output of 20 dm3

/min. Further increase of the output causes a decrease of the value „tL” and an increase of „Z”.

The examined technological factors of the refining process did not cause any significant changes in the microstructure of silumin 226.

A comparative analysis involving the evaluation of the effectiveness of investment projects can be based on various rules indicating

selection of the most favorable decisions. The dynamic methods for assessment of investment projects discussed in this article, which

consider the possibility of modifying the predetermined investment options, are quite complex and difficult to implement. They are used

both in the construction phase of the new company, as well as in its subsequent modernization. The assessments should be characterized

by a high coefficient of the economic efficiency. The, observed in practice, high dynamic variability of both the external and internal

conditions under which the company operates is the reason why in the process of calculating the economic efficiency of investment

projects, there is a significant number of random parameters affected by high uncertainty and risk. Investments in the metallurgical

industry are characterized by a relatively long cycle of implementation and operation. These are capital-intensive projects and often

mistakenly taken investment decisions end in failure of the investment project and, consequently, in the collapse of the company. In

addition, the applied methods of risk assessment of investment projects, especially the dynamic ones, should be fully understood by

managerial staff and constitute an easy to use, yet accurate tool for improving the efficiency of the company.

This article presents a computer system for the identification of casting defects using the methodology of Case-Based Reasoning. The

system is a decision support tool in the diagnosis of defects in castings and is designed for small and medium-sized plants, where it is not

possible to take advantage of multi-criteria data. Without access to complete process data, the diagnosis of casting defects requires the use

of methods which process the information based on the experience and observations of a technologist responsible for the inspection of

ready castings. The problem, known and studied for a long time, was decided to be solved with a computer system using a CBR (CaseBased

Reasoning) methodology. The CBR methodology not only allows using expert knowledge accumulated in the implementation

phase, but also provides the system with an opportunity to "learn" by collecting new cases solved earlier by this system. The authors

present a solution to the system of inference based on the accumulated cases, in which the main principle of operation is searching for

similarities between the cases observed and cases stored in the knowledge base.

This article presents a practical solution in the form of implementation of agent-based platform for the management of contracts in

a network of foundries. The described implementation is a continuation of earlier scientific work in the field of design and theoretical

system specification for cooperating companies [1]. The implementation addresses key design assumptions - the system is implemented

using multi-agent technology, which offers the possibility of decentralisation and distributed processing of specified contracts and tenders.

The implemented system enables the joint management of orders for a network of small and medium-sized metallurgical plants, while

providing them with greater competitiveness and the ability to carry out large procurements. The article presents the functional aspects of

the system - the user interface and the principle of operation of individual agents that represent businesses seeking potential suppliers or

recipients of services and products. Additionally, the system is equipped with a bi-directional agent translating standards based on

ontologies, which aims to automate the decision-making process during tender specifications as a response to the request.

The work is a continuation of research on the use water mist cooling in order to increase efficiency of die-casting aluminum alloys using

multipoint water mist cooling system. The paper presents results of investigation of crystallization process and microstructure of synthetic

hypereutectic AlSi20 alloy. Casts were made in permanent mold cooled with water mist stream. The study was conducted for unmodified

AlSi20 alloy and modified with phosphorus, titanium and boron on the research station allowing sequential multipoint cooling using a

dedicated program of computer control. The study demonstrated that the use of mold cooled with water mist stream allows the formation

of the microstructure of hypereutectic silumins. A wide range of solidification temperature of hypereutectic silumins increases the

potential impact of changes in the cooling rate on a size, a number and a morphology of preeutectic silicon and eutectic α+β (Al+Si).

The herein paper contains the results of investigations on a new type of cellulose blend used for the manufacture of profiles applied in the

process of making gating systems in the foundry industry. A standard cellulose profile was subjected to an experiment. During the

experiment the profile was filled with a liquid cast iron and at the same time the temperatures of the liquid metal crystallizing inside the

profile were measured as well as the temperature of the outer layer of the profile was controlled. Further, the microstructure of the cast

iron, which crystallized out inside the cellulose profile, was analysed and the cellulose, thermally degraded after the experiment, was

verified with the use of the chemical analysis method. Moreover, a quality analysis of the original as well as the degraded cellulose profile

was run with the use of the FTIR infrared spectroscopy. The presented results revealed that the cellulose blend is aluminium silicate

enriched and contains organic binder additives. The cast iron, which crystallized out, tended to have an equilibrium pearlitic structure with

the release of graphite and carbides. The generation of disequilibrium ausferrite phases was also observed in the structure.