The dry sliding wear behavior of heat-treated super duplex stainless steel AISI 2507 was examined by taking pin-on-disc type of wear-test

rig. Independent parameters, namely applied load, sliding distance, and sliding speed, influence mainly the wear rate of super duplex

stainless steel. The said material was heat treated to a temperature of 850°C for 1 hour followed by water quenching. The heat treatment

was carried out to precipitate the secondary sigma phase formation. Experiments were conducted to study the influence of independent

parameters set at three factor levels using the L27 orthogonal array of the Taguchi experimental design on the wear rate. Statistical

significance of both individual and combined factor effects was determined for specific wear rate. Surface plots were drawn to explain the

behavior of independent variables on the measured wear rate. Statistically, the models were validated using the analysis of variance test.

Multiple non-linear regression equations were derived for wear rate expressed as non-linear functions of independent variables. Further,

the prediction accuracy of the developed regression equation was tested with the actual experiments. The independent parameters

responsible for the desired minimum wear rate were determined by using the desirability function approach. The worn-out surface

characteristics obtained for the minimum wear rate was examined using the scanning electron microscope. The desired smooth surface was

obtained for the determined optimal condition by desirability function approach.

The scope of work included the launch of the process of refining slag suspension in a gas oven using a variety of technological additives.

After the refining process (in the context of copper recovery), an assessment of the effect of selected reagents at the level of the slag

refining suspension (in terms of copper recovery). Method sieve separated from the slag waste fraction of metallic, iron - silicate and

powdery waste. Comparison of these photographs macroscopic allowed us to evaluate the most advantageous method of separating

metallic fraction from the slag. After applying the sample A (with KF2 + NaCl) we note that in some parts of the slag are still large

amounts of metallic fraction. The fraction of slag in a large majority of the elements has the same size of 1 mm, and a larger portion of the

slag, the size of which is from 2 to 6 mm. Definitely the best way is to remove the copper by means of the component B (with NaCl ) and

D (with KF2

). However, as a result of removing the copper by means of component C (with CaO) were also obtained a relatively large

number of tiny droplets of copper, which was problematic during segregation. In both cases we were able to separate the two fractions in a

fast and simple manner.

The paper presents results of the possibility of adapting the Althoff-Radtke test for High Chromium Cast Iron. The Althoff-Radtke test is a

clump attempt used for steel. The Althoff-Radtke test has four different lengths of clamp which qualifies it as a test to quantitatively take

into account different kinds of shrinkage ΔL. The length of the slot of the cracked corner and the length of each staple (50 - 350 mm) are

the parameters tendency to cast cracks. Castings of white cast iron have a high tendency to hot cracking due to the large range of

solidification temperatures, unfavorable kinetics parameters of shrinkage, and especially a lack of expansion before shrinkage. Shrinkage

of high chromium white cast iron is similar to the shrinkage of cast steel, and is approximately 2%. Therefore it is important to test

susceptibility to hot cracks. Research was carried out under industrial conditions. Four melts were performed, one of the initial chemical

composition and the other three modified by different amounts of Fe-Ti, respectively, 0.25%, 0.5% and 0.75% Fe-Ti. The propensity for

hot cracking was based on the observation of the dark surface in the corner of the sample. The study shows that the Althoff-Radtke test can

be adapted to determine the tendency for hot cracking of high chromium cast iron. It should however be noted that the test results cannot be

compared with those for other alloys.

The presence of the chunky graphite is unwanted in the cast iron with the spheroidal graphite for this significantly lowers the properties of

the ductile iron. This shape of the graphite is formed as the result of the slow cooling rate of the castings with large thermal point and also

due to the presence of the elements which suppress the formation of the spheroidal graphite and support formation of the chunky graphite.

The spheroidal graphite present in the ductile iron assures the excellent mechanical properties, while the chunky graphite significantly

reduces those properties of the ductile iron. Therefore it is of importance to assume conditions under which prevented is the formation of

the chunky graphite. The casts were carried out under the conditions of the regular operation of the foundry and tested were various types

of modifiers and inoculators and also pre-inoculators containing the elements suppressing the formation of the chunky graphite (Al, Sb a

Ba). Applied were also the chromium breaker core to suppress the formation chunky graphite which was present in the structure in the

places after the feeders elimination. As whole, executed were eight casts with various types of the modifiers and inoculators.

In this paper an attempt to determine the relationship between the electrical resistivity and the tensile strength and hardness of cast iron of

carbon equivalent in the range from 3.93% to 4.48%. Tests were performed on the gray cast iron for 12 different melts with different

chemical composition. From one melt poured 6 samples. Based on the study of mechanical and electro-resistive determined variation

characteristics of tensile strength, hardness and resistivity as a function of the carbon equivalent. Then, regression equations were

developed as power functions describing the relationship between the resistivity of castings and their tensile strength and hardness. It was

found a high level of regression equations to measuring points, particularly with regard to the relationship Rm=f(ρ). The obtained

preliminary results indicate the possibility of application of the method of the resistance to rapid diagnostic casts on the production line,

when we are dealing with repeatable production, in this case non variable geometry of the product for which it has been determinated

before a regression equation.

The surfacing technologies are used for constitution of protection layer against wear and is destined for obtaining coating with high

hardness. Among many weldings methods currently used to obtain the hard surface layer one of the most effective way of hardfacing is

using flux cored arc welding. This additional material gives more possibilities to make expected hard surface layer.

Chemical composition, property and economic factors obtained in flux cored wire are much richer in comparison to these obtained with

other additional materials. This is the reason why flux cored wires give possibilities of application this kind of material for improving

surface in different sectors of industry.

In the present paper the imperfection in the layers was used for hardfacing process in different situations to show the possible application

in the surface layer. The work presents studies of imperfection of the welds, contains the picture of microstructures, macrostructures and

shows the results of checking by visual and penetrant testing methods.

This paper discusses the mechanical properties of a material fabricated from commercially available metal powder mixtures designed for

use as a metal matrix of diamond impregnated composites. The mixtures with the catalogue numbers CSA and CSA800 provided by a

Chinese producer are suitable for experimental laboratory testing. The specimens were fabricated in a graphite mould using hot pressing.

The material was tested for density, porosity, hardness, and tensile strength under static loading. A scanning electron microscope (SEM)

was used to analyze the microstructure and cleavage fracture of broken specimens. It was essential to determine how the chemical

composition and the fabrication process affected the microstructure and properties of the material. The properties of the sinters were

compared with those of hot pressed specimens fabricated from sub-micron size cobalt powder (Cobalt SMS). Although the as-consolidated

material is inferior to cobalt, it displays a favourable combination of hardness, yield strength and ductility, and seems to have a great

potential for moderate and general purpose applications.

The article presents research results of physico-chemical and environmental issues for the dust generated during dedusting of the

installation for the processing and preparation of moulding sand with bentonite. Particular attention was paid to the content of heavy

metals and emission of gases from the BTEX group, which is one of the determinants of the moulding sands harmfulness for the

environment. The analysis of heavy metals in the test samples indicate that there is an increase of the content of all metals in the dust

compared to the initial mixture of bentonite. The most significant (almost double) increase observed for zinc is probably related to the

adsorption of this element on the dust surface by contact with the liquid metal. The study showed, that dust contained more than 20% of

the amount of montmorillonite and had a loss on ignition at a similar level. The addition of 1% of dust to the used moulding sand results in

almost 30% increase in the total volume of gases generated in casting processes and nearly 30% increase of the benzene emission.

Development of open cellular metal foam technology based on investment casting applying the polyurethane pattern is discussed.

Technological process comprises preparing of the ceramic mold applying PUR foam as the pattern, firing of the mold, pouring of the

liquid Zn-Al alloy into the mold and washing out of the ceramic material from cellular casting. Critical parameters such as the temperature

of mold and poured metal, design of gating system affected by metalostatic pressure allowed to produce castings with cellular structure

characterized by the open porosity.

Metal cellular foams with the open porosity embedded in phase change material (PCM) enhance heat transfer and reduce time operations

in energy storage systems. Charging and discharging were performed at the laboratory accumulator by heating and cooling with flowing

water characterized by the temperatures of 97-100oC. Temperature measurements were collected from 7 different thermocouples located

in the accumulator. In relation to the tests with pure paraffin, embedding of the metal Zn-Al cellular foam in paraffin significantly

decreases temperature gradients and melting time of paraffin applied as PCM characterized by the low thermal conductivity. Similarly,

reduction of discharging time by this method improves the efficiency of thermal energy storage system applied in solar power plants or for

the systems of energy efficient buildings.

Heating process in the domain of thin metal film subjected to a strong laser pulse are discussed. The mathematical model of the process

considered is based on the dual-phase-lag equation (DPLE) which results from the generalized form of the Fourier law. This approach is,

first of all, used in the case of micro-scale heat transfer problems (the extremely short duration, extreme temperature gradients and very

small geometrical dimensions of the domain considered). The external heating (a laser action) is substituted by the introduction of internal

heat source to the DPLE. To model the melting process in domain of pure metal (chromium) the approach basing on the artificial mushy

zone introduction is used and the main goal of investigation is the verification of influence of the artificial mushy zone ‘width’ on the

results of melting modeling. At the stage of numerical modeling the author’s version of the Control Volume Method is used. In the final

part of the paper the examples of computations and conclusions are presented.

Statistical Process Control (SPC) based on the Shewhart’s type control charts, is widely used in contemporary manufacturing industry,

including many foundries. The main steps include process monitoring, detection the out-of-control signals, identification and removal of

their causes. Finding the root causes of the process faults is often a difficult task and can be supported by various tools, including datadriven

mathematical models. In the present paper a novel approach to statistical control of ductile iron melting process is proposed. It is

aimed at development of methodologies suitable for effective finding the causes of the out-of-control signals in the process outputs,

defined as ultimate tensile strength (Rm) and elongation (A5), based mainly on chemical composition of the alloy. The methodologies are

tested and presented using several real foundry data sets. First, correlations between standard abnormal output patterns (i.e. out-of-control

signals) and corresponding inputs patterns are found, basing on the detection of similar patterns and similar shapes of the run charts of the

chemical elements contents. It was found that in a significant number of cases there was no clear indication of the correlation, which can

be attributed either to the complex, simultaneous action of several chemical elements or to the causes related to other process variables,

including melting, inoculation, spheroidization and pouring parameters as well as the human errors. A conception of the methodology

based on simulation of the process using advanced input - output regression modelling is presented. The preliminary tests have showed

that it can be a useful tool in the process control and is worth further development. The results obtained in the present study may not only

be applied to the ductile iron process but they can be also utilized in statistical quality control of a wide range of different discrete

processes.

Very well-known advantages of aluminum alloys, such as low mass, good mechanical properties, corrosion resistance, machining-ability,

high recycling potential and low cost are considered as a driving force for their development, i.e. implementation in new applications as

early as in stage of structural design, as well as in development of new technological solutions. Mechanical and technological properties of

the castings made from the 3xx.x group of alloys depend mainly on correctly performed processes of melting and casting, design of a

mould and cast element, and a possible heat treatment.

The subject-matter of this paper is elaboration of a diagrams and dependencies between parameters of dispersion hardening (temperatures

and times of solutioning and ageing treatments) and mechanical properties obtained after heat treatment of the 356.0 (EN AC AlSi7Mg)

alloy, enabling full control of dispersion hardening process to programming and obtaining a certain technological quality of the alloy in

terms of its mechanical properties after performed heat treatments. Obtained results of the investigations have enabled obtainment of a

dependencies depicting effect of parameters of the solutioning and ageing treatments on the mechanical properties (Rm, A5 and KC impact

strength) of the investigated alloy. Spatial diagrams elaborated on the basis of these dependencies enable us to determine tendencies of

changes of the mechanical properties of the 356.0 alloy in complete analyzed range of temperature and duration of the solutioning and

ageing operations.

The results of investigations of spent moulding sands taken from the mould at various distances from the surface of the produced casting,

are presented in the paper. The casting mould was made with an application of the cooling system of the metal core in order to increase the

cooling rate of the ladle casting. As temperature measurements in the mould indicated the heat flow from the metal did not create

conditions for the complete burning of a moulding sand. The analysis was performed to find out changes of spent moulding sands caused

by degradation and destruction processes of organic binders. Conditions occurring in the casting mould were discussed on the bases of

testing: ignition losses, dusts contents, pH reactions and the surface morphology of the moulding sand samples. Factors limiting the

effective mould degassing were pointed out. Operations, possible for realization, which can limit the reasons of a periodical occurrence of

increased amounts of casting defects due to changing gas evolution rates being the result of the technological process, were also indicated.

The publication presents the results of examination of selected carburizers used for cast iron production with respect to their electric

resistance. Both the synthetic graphite carburizers and petroleum coke (petcoke) carburizers of various chemical composition were

compared. The relationships between electrical resistance of tested carburizers and their quality were found. The graphite carburizers

exhibited much better conductivity than the petcoke ones. Resistance characteristics were different for the different types of carburizers.

The measurements were performed according to the authors’ own method based on recording the electric current flow through the

compressed samples. The samples of the specified diameter were put under pressure of the gradually increased value (10, 20, 50, 60, and

finally 70 bar), each time the corresponding value of electric resistance being measured with a gauge of high accuracy, equal to 0.1μΩ.

The higher pressure values resulted in the lower values of resistance. The relation between both the thermal conductance and the electrical

conductance (or the resistance) is well known and mentioned in the professional literature. The results were analysed and presented both in

tabular and, additionally, in graphic form.

The new investigation method of the kinetics of the gas emission from moulding sands used for moulds and cores is presented in this

paper. The gas evolution rate is presented not only as a function of heating time but also as a function of instantaneous temperatures. In

relation to the time and heating temperature the oxygen and hydrogen contents in evolving gases was also measured. This method was

developed in the Laboratory of Foundry Moulds Technology, Faculty of Foundry Engineering, AGH. Gas amounts which are emitted from

the moulding sand at the given temperature recalculated to the time unit (kinetics) are obtained in investigations. Results of investigations

of moulding sand with furan resin are presented - as an example - in the paper.

Growing emission requirements are forcing the foundry industry to seek new, more environmentally friendly solutions. One of the

solutions may be the technologies of preparing moulding and core sands using organic biodegradable materials

as binders. However, not only environmental requirements grow but also those related to the technological properties

of moulding sand. Advancing automation and mechanization of the foundry industry brings new challenges related to the moulding sands.

Low elasticity may cause defects during assembly of cores or moulds by the manipulators.

The paper presents the study of flexibility in the room temperature according to new method and resistance to thermal deformation of selfhardening

moulding sands with furfuryl resin, containing biodegradable material PCL. The task of the new additive is to reduce the

moulding sands harmfulness to the environment and increase its flexibility in the room temperature. The impact of the additive and the

effect of the amount of binder on the properties of mentioned moulding sands were analysed. Studies have shown that the use of 5% of

PCL does not change the nature of the thermal deformation curve, improves the bending strength of tested moulding mixtures and

increases their flexibility at room temperature.

The most important feature of bells is their sound. Its clarity and beauty depend, first of all, on the bell’s geometry - particularly the shape

of its profile, but also on the quality of alloy used to its cast. Hence, if the melting and pouring parameters could influence the alloy’s

properties, what influence they would have on the frequencies of bell’s tone. In the article authors present their own approaches to find

answers on that and more questions.

The purpose of this study was to establish a relationship between the type of wall connection used in the cast grates, which are part of the

equipment operating in furnaces for heat treatment and thermal-chemical treatment, and stresses generated in these grates during the

process of rapid cooling. The places where the grate walls are connected to each other are usually characterized by the thickness larger

than the remaining parts of walls. Temperature variations in those places are responsible for the formation of hot spots, and in the hot spots

temperature changes much more slowly. The type of wall connection shapes the temperature gradient in the joint cross-section, and hence

also the value of thermal stresses generated during cooling. In this study, five different designs of the grates were compared; the difference

in them was the type of the designed wall connection. The following design variants were adopted in the studies: X connections with and

without holes, T connections with and without technological recesses, and R (ring) connection. Numerical analysis was performed to

examine how the distribution of temperature changes in the initial phases of the cooling process. The obtained results served next as a tool

in studies of the stress distribution in individual structures. The analysis were carried out by FEM in Midas NFX 2014 software. Based on

the results obtained, the conclusions were drawn about the impact of different types of wall connections on the formation of thermal

stresses in cast grates.

The paper presents results of metallographic examination of faults occurring in the course of founding thin-walled cast-iron castings in

furan resin sand molds. A non-conformance of the scab type was Observed on surface of the casting as well as sand buckles and cold

shots. Studied the chemical composition by means of a scanning electron microscope in a region of casting defects: microanalysis point

and microanalysis surface. Around the observed defects discloses high concentration of oxides of iron, manganese and silicon.

A computer simulation of the casting process has been carried out with the objective to establish the cause of occurrence of cold shots on

casting surface. The simulation was carried out with the use of NovaFlow & Solid program. We analyzed the flowing metal in the mold

cavity. The main reason for the occurrence of casting defects on the surface of the casting was gating system, which caused turbulent flow

of metal with a distinctive splash stream of liquid alloy.

The article presents the results of a comparative analysis of the metal substructure for dental prosthesis made from a Co-Cr-Mo-W alloy by

two techniques, i.e. precision investment casting and selective laser melting (SLM). It was found that the roughness of the raw surface of

the SLM sinter is higher than the roughness of the cast surface, which is compensated by the process of blast cleaning during metal

preparation for the application of a layer of porcelain. Castings have a dendritic structure, while SLM sinters are characterized by a

compact, fine-grain microstructure of the hardness higher by about 100 HV units. High performance and high costs of implementation the

SLM technology are the cause to use it for the purpose of many dental manufacturers under outsourcing rules. The result is a reduction in

manufacturing costs of the product associated with dental work time necessary to scan, designing and treatment of sinter compared with

the time needed to develop a substructure in wax, absorption in the refractory mass, casting, sand blasting and finishing. As a result of

market competition and low cost of materials, sinter costs decrease which brings the total costs related to the construction unit making

using the traditional method of casting, at far less commitment of time and greater predictability and consistent sinter quality.

The paper concerns evaluation of the coefficient of friction characterising a friction couple comprising a commercial brake disc cast of

flake graphite grey iron and a typical brake pad for passenger motor car. For the applied interaction conditions, the brake pressure of

0.53 MPa and the linear velocity measured on the pad-disc trace axis equalling 15 km/h, evolution of the friction coefficient μ values were

observed. It turned out that after a period of 50 minutes, temperature reached the value 270°C and got stabilised. After this time interval,

the friction coefficient value also got stabilised on the level of μ = 0.38. In case of a block in its original state, stabilisation of the friction

coefficient value occurred after a stage in the course of which a continuous growth of its value was observed up to the level μ = 0.41 and

then a decrease to the value μ = 0.38. It can be assumed that occurrence of this stage was an effect of an initial running-in of the friction

couple. In consecutive abrasion tests on the same friction couple, the friction coefficient value stabilisation occurred after the stage of

a steady increase of its value. It can be stated that the stage corresponded to a secondary running-in of the friction couple. The observed

stages lasted for similar periods of time and ended with reaching the stabile level of temperature of the disc-pad contact surface.

Paper present a thermal analysis of laser heating and remelting of EN AC-48000 (EN AC-AlSi12CuNiMg) cast alloy used mainly for

casting pistons of internal combustion engines. Laser optics were arranged such that the impingement spot size on the material was a

circular with beam radius rb changes from 7 to 1500 m. The laser surface remelting was performed under argon flow. The resulting

temperature distribution, cooling rate distribution, temperature gradients and the depth of remelting are related to the laser power density

and scanning velocity. The formation of microstructure during solidification after laser surface remelting of tested alloy was explained.

Laser treatment of alloy tests were perform by changing the three parameters: the power of the laser beam, radius and crystallization rate.

The laser surface remelting needs the selection such selection of the parameters, which leads to a significant disintegration of the structure.

This method is able to increase surface hardness, for example in layered castings used for pistons in automotive engines.

Investigation of the tensile and fatigue properties of cast magnesium alloys, created by the heated mold continuous casting process (HMC),

was conducted. The mechanical properties of the Mg-HMC alloys were overall higher than those for the Mg alloys, made by the

conventional gravity casting process (GC), and especially excellent mechanical properties were obtained for the Mg97Y2Zn1

-HMC alloy.

This was because of the fine-grained structure composed of the -Mg phases with the interdendritic LPSO phase. Such mechanical

properties were similar levels to those for conventional cast aluminum alloy (Al84.7Si10.5Cu2.5Fe1.3Zn1 alloys: ADC12), made by the GC

process. Moreover, the tensile properties (UTS and f

) and fatigue properties of the Mg97Y2Zn1

-HMC alloy were about 1.5 times higher

than that for the commercial Mg90Al9Zn1

-GC alloy (AZ91). The high correlation rate between tensile properties and fatigue strength

(endurance limit: l

) was obtained. With newly proposed etching technique, the residual stress in the Mg97Y2Zn1 alloy could be revealed,

and it appeared that the high internal stress was severely accumulated in and around the long-period stacking-order phases (LPSO). This

was made during the solidification process due to the different shrinkage rate between α-Mg and LPSO. In this etching technique, microcracks

were observed on the sample surface, and amount of micro-cracks (density) could be a parameter to determine the severity of the

internal stress, i.e., a large amount to micro-cracks is caused by the high internal stress.

The lifetime of guide grates in pusher furnaces for heat treatment could be increased by raising the flexibility of their structure through, for

example, the replacement of straight ribs, parallel to the direction of grate movement, with more flexible segments. The deformability of

grates with flexible segments arranged in two orientations, i.e. crosswise (perpendicular to the direction of compression) and lengthwise

(parallel to the direction of compression), was examined. The compression process was simulated using SolidWorks Simulation program.

Relevant regression equations were also derived describing the dependence of force inducing the grate deformation by 0.25 mm ‒ modulus

of grate elasticity ‒ on the number of flexible segments in established orientations. These calculations were made in Statistica and Scilab

programs. It has been demonstrated that, with the same number of segments, the crosswise orientation of flexible segments increases the

grate structure flexibility in a more efficient way than the lengthwise orientation. It has also been proved that a crucial effect on the grate

flexibility has only the quantity and orientation of segments (crosswise / lengthwise), while the exact position of segments changes the

grate flexibility by less than 1%.