Nauki Techniczne

Archives of Foundry Engineering

Zawartość

Archives of Foundry Engineering | 2016 | No 3 |

Abstrakt

Sand samples with furan binder were prepared using Sand, Furfuryl Alcohol and Toluene Sulfonic Acid with ratio 100:0.85:0.30. To

identify and quantify gases releasing from furan binder various studies like FTIR, TGA and GC-MS were carried out. After analyzing our

materials using above mentioned characterizations the chemical formula of the Resin and Binder and amount of gases releasing from

composition were confirmed. After studying various reports on pyrolysis process of furan binder calculation of the % of various gases

emitting during pyrolysis process of furan was carried out. Sample of gas collected from mold was analyzed using GC-MS. Based on GCMS

measurement various gases emitting from furan sand mold were identified and their amount were calculate and compared with the

international standers of permissible gas emission limits in a foundry. The purpose of this paper is to assist foundries in pollution

prevention by devising clean technologies which maintain or improve the quality of ambient surrounding. This paper aimed at

minimization of pollution of air by using various techniques.

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The paper presents the results concerning impact of modification (volume and surface techniques), pouring temperature and mould

temperature on stereological parameters of macrostructure in IN713C castings made using post-production scrap. The ability to adjust the

grain size is one of the main issues in the manufacturing of different nickel superalloy castings used in aircraft engines. By increasing the

grain size one can increase the mechanical properties, like diffusion creep resistance, in higher temperatures. The fine grained castings. on

the other hand, have higher mechanical properties in lower temperatures and higher resistance to thermal fatigue. The test moulds used in

this study, supplied by Pratt and Whitney Rzeszow, are ordinarily used to cast the samples for tensile stress testing. Volume modification

was carried out using the patented filter containing cobalt aluminate. The macrostructure was described using the number of grains per

mm2

, mean grain surface area and shape index. Obtained results show strong relationship between the modification technique, pouring

temperature and grain size. There was no significant impact of mould temperature on macrostructure.

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The paper analyses specific defects of castings produced by semi-solid casting process, especially rheocasting method SEED, which uses

mechanical swirling for reaching proper structure in semisolid state with high content of solid fraction. Heat treated alloy AlSi7Mg0.3 was

applied for producing an Engine Bracket casting part. For observing structure, metallographic observation by light and SEM microscopy

was used. To analyse the process, software ProCAST was used to simulate the movements in shot chamber and filling of the mold.

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Trial series of cast alloy MO59 obtained from qualified scrap was investigated. SEM and TEM of resulting precipitates were conducted.

The SEM analysis demonstrated the dependence of silicon, phosphorus, iron, chromium and nickel in the composition of the so-called

hard precipitates. TEM analysis showed the formation of phase AlFeSi and AlCr. Made studies have shown the important role of the

composition of the batch melts brass CuZn39Pb2 type. The analysis of SEM and TEM resulting precipitates pointed to the formation of

various forms of divisions, only one of which was described in the literature character of the so-called hard inclusions. The SEM studies

demonstrated the dependence of the occurrence of inclusions rich in silicon, phosphorus, iron, chromium and nickel. In contrast, additional

TEM analysis indicated the formation of AlFeSi phase type and AlCr. The results of the analyses referred to the structure of the batch. Due

to the difficulty of obtaining recycled materials that do not contain these elements necessary to carry out further analyzes in the direction

of defining the role of phosphorus in the formation of the so-called hard inclusions.

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Issues connected with high quality casting alloys are important for responsible construction elements working in hard conditions.

Traditionally, the quality of aluminium casting alloy refers to such microstructure properties as the presence of inclusions and intermetallic

phases or porosity. At present, in most cases, Quality index refers to the level of mechanical properties – especially strength parameters,

e.g.: UTS, YS, HB, E (Young’s Modulus), K1c (stress intensity factor). Quality indexes are often presented as a function of density.

However, generally it is known, that operating durability of construction elements depends both on the strength and plastic of the material.

Therefore, for several years now, in specialist literature, the concept of quality index (QI) was present, combines these two important

qualities of construction material. The work presents the results of QI research for casting hypoeutectic silumin type EN AC-42100

(EN AC-AlSi7Mg0.3), depending on different variants of heat treatment, including jet cooling during solution treatment.

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This preliminary study characterizes the bronze metalworking on a defensive settlement of the Lusatian culture in former Kamieniec

(Chełmno land, Poland) as it is reflected through casting workshop recovered during recent excavations. Among ready products, the ones

giving evidence of local metallurgy (e.g. casting moulds and main runners) were also identified. With the shrinkage cavities and dendritic

microstructures revealed, the artifacts prove the implementing a casting method by the Lusatian culture metalworkers. The elemental

composition indicates application of two main types of bronzes: Cu-Sn and Cu-Pb. Aside these main alloying additions, some natural

impurities such as silver, arsenic, antimony and nickel were found which may be attributed to the origin of the ore and casting technology.

The collection from Kamieniec was described in terms of its structure and composition. The investigations were made by means of the

energy dispersive X-ray fluorescence spectroscopy (ED-XRF), scanning electron microscopy (SEM) coupled with an energy dispersive Xray

analysis system (EDS) and optical microscopy (OM). In order to fingerprint either local or non-local profile of the alloys, the ED-XRF

data-set was statistically evaluated using a factor analysis (FA).

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The present research was conducted on thin-walled castings with 5 mm wall thicknesses. This study addresses the effect of the influence of

different master alloys, namely: (1) Al-5%Ti-1%B, (2) Al-5%Ti and (3) Al-3%B, respectively on the structure and the degree of

undercooling (ΔTα = Tα-Tmin, where Tα - the equilibrium solidification temperature, Tmin - the minimum temperature at the beginning of

α(Al) solidification) of an Al-Cu alloy. The process of fading has been investigated at different times spent on the refinement treatment ie.

from 3, 20, 45 and 90 minutes respectively, from the dissolution of master alloys. A thermal analysis was performed (using a type-S

thermocouple) to determine cooling curves. The degree of undercooling and recalescence were determined from cooling and solidification

curves, whereas macrostructure characteristics were conducted based on a metallographic examination. The fading effect of the refinement

of the primary structure is accompanied by a significant change in the number (dimension) of primary grains, which is strongly correlated

to solidification parameters, determined by thermal analysis. In addition to that, the analysis of grain refinement stability has been shown

with relation to different grain refinements and initial titanium concentration in Al-Cu base alloy. Finally, it has been shown that the

refinement process of the primary structure is unstable and requires strict metallurgical control.

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The welding technologies are widely used for design of protection layer against wear and corrosion. Hardfacing, which is destined for

obtaining coatings with high hardness, takes special place in these technologies. One of the most effective way of hardfacing is using self

shielded flux cored arc welding (FCAW-S). Chemical composition obtained in flux cored wire is much more rich in comparison to this

obtained in solid wire. The filling in flux cored wires can be enriched for example with the mixture of hard particles or phases with

specified ratio, which is not possible for solid wires. This is the reason why flux cored wires give various possibilities of application of this

kind of filler material for improving surface in mining industry, processing of minerals, energetic etc. In the present paper the high

chromium and niobium flux cored wire was used for hardfacing process with similar heat input. The work presents studies of

microstructures of obtained coatings and hardness and geometric properties of them. The structural studies were made with using optical

microscopy and X- ray diffraction that allowed for identification of carbides and other phases obtained in the structures of deposited

materials. Investigated samples exhibit differences in coating structures made with the same heat input 4,08 kJ/mm. There are differences

in size, shape and distribution of primary and eutectic carbides in structure. These differences cause significant changes in hardness of

investigated coatings.

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The paper presents the microstructure and selected properties of ausferritic nodular cast iron annealed at the temperature 520 and 550°C.

This choice was dictated by the temperatures used in the practice of nitriding. Nodular graphite in cast iron was obtained with use of

Inmold process. Cast iron containing molybdenum and copper ensuring obtaining an ausferrite in the cast iron matrix without the use of

heat treatment of castings was tested. The effect of annealing temperature on the microstructure and the kind of fracture of the ausferritic

nodular cast iron was presented. The effect of an annealing temperature on hardness, impact strength and the microhardness of ausferritic

nodular cast iron matrix was shown too. The lamellar structure of phases in the cast iron matrix after annealing has been ascertained. There

has been an increase in hardness of an annealed cast iron and microhardness of its matrix. The reduction in the impact strength of the cast

iron annealed at 520 and 550°C was approximately 10-30%. Both an increase in the hardness of cast iron as well as an decrease in its

impact strength is probably due to the separation of secondary carbides during the heat treatment.

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Ensuring the required quality of castings is an important part of the production process. The quality control should be carried out in a fast

and accurate way. These requirements can be met by the use of an optical measuring system installed on the arm of an industrial robot. In

the article a methodology for assessing the quality of robotic measurement system to control certain feature of the casting, based on the

analysis of repeatability and reproducibility is presented. It was shown that industrial robots equipped with optical measuring systems have

the accuracy allowing their use in the process of dimensional control of castings manufactured by lost-wax process, permanent-mould

casting, and pressure die-casting.

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The paper presents a practical example of improvement of foundry production systems in terms of post-finishing of nodular iron castings

produced in the conditions of bulk production for automotive industry. The attention was paid to high labour-intensive efforts, which

are difficult to be subjected to mechanization and automation. The times of actions related to grinding processing of castings in three

grinding positions connected with a belt conveyor were estimated with the use of a time study method. A bottleneck as well as limiting

factors were specified in a system. A number of improvements were proposed, aimed at improving work organization on the castings postfinishing

line. An analysis of work ergonomics at the workplace was made in order to eliminate unnecessary and onerous for the employee

actions. A model of production system using the Arena software, on which a simulation experiment was conducted, was drawn up in order

to visualize the analysed phenomena. The effects of the project were shown on graphs comparing times, costs, work ergonomics and

overall efficiency of production equipment indicator.

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In the paper, a relationship between chemical composition of Ni-Mn-Cu cast iron and its structure, hardness and corrosion resistance is

determined. The examinations showed a decrease of thermodynamic stability of austenite together with decreasing nickel equivalent value,

in cast iron solidifying according to both the stable and the metastable systems. As a result of increasing degree of austenite

transformation, the created martensite caused a significant hardness increase, accompanied by small decline of corrosion resistance. It was

found at the same time that solidification way of the alloy and its matrix structure affect corrosion resista

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Within the presented work, the effect of austenite transformation on abrasive wear as well as on rate and nature of corrosive destruction

of spheroidal Ni-Mn-Cu cast iron was determined. Cast iron contained: 3.1÷3.4 %C, 2.1÷2.3 %Si, 2.3÷3.3 %Mn, 2.3÷2.5 %Cu and

4.8÷9.3 %Ni. At a higher degree of austenite transformation in the alloys with nickel equivalent below 16.0%, abrasive wear resistance

was significantly higher. Examinations of the corrosion resistance were carried out with the use of gravimetric and potentiodynamic

method. It was shown that higher degree of austenite transformation results in significantly higher abrasive wear resistance and slightly

higher corrosion rate, as determined by the gravimetric method. However, results of potentiodynamic examinations showed creation

of a smaller number of deep pinholes, which is a favourable phenomenon from the viewpoint of corrosion resistance.

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In the paper the reasons for steam pipeline’s elbow material rupture, made of steel 13CrMo4-5 (15HM) that is being used in the energetics.

Based on the mechanical properties in the ambient temperature (Rm, Rp0,2 and elongation A5) and in the increased temperature (Rp0,2t

) it

was found, that the pipeline elbow’s material sampled from the ruptured area has lower Rp0,2 i Rp0,2t by around 2% than it is a requirement

for 13CrMo4-5 steel in it’s base state. The damage appeared as a result of complex stress state, that substantially exceeded the admissible

tensions, what was the consequence of considerable structure degradation level. As a result of the microstructure tests on HITACHI S4200

microscope, the considerable development of the creeping process associates were found. Also the advances progress of the microstructure

degradation was observed, which is substantial decomposition of bainite and multiple, with varied secretion size, and in most cases

forming the micro cracks chains. With the use of lateral micro sections the creeping voids were observed, that creates at some places the

shrinkage porosities clusters and micro pores.

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Moulding properties of Isasa River Sand bonded with Ipetumodu clay (Ife-North Local Government Area, Osun State, Nigeria) were

investigated. American Foundry men Society (AFS) standard cylindrical specimens 50mm diameter and 50mm in height were prepared

from various sand and clay ratios (between 18% and 32%) with 15% water content. The stress-strain curves were generated from a

universal strength testing machine. A flow factor was calculated from the inclination of the falling slope beyond the maximum

compressive strength. The result shows that the flowability of the samples increases from 18% to 26% clay content, its maximum value

was attained at 26% and then it decreases from 30% to 32% clay content. The green compressive strength, dry compressive strength and

air permeability values obtained from the mould samples were in accordance with standard values used in foundry practice. The x-ray

diffraction test shows that the sand contains silicon oxide (SiO2), Aluminium oxide (Al2O3), and Aluminium silicate (Al6Si2O13). The

mould samples were heated to a temperature of 1200 o

C to determine the sintering temperature; fussion did not take place at this

temperature. The results showed that the sand and clay mixture can be used to cast ferrous and non-ferrous alloys.

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Refinement is one of the most energy consuming technological process, aimed at obtaining mineral raw materials of the proper grain size.

Cast structural elements such as jaws or hammers in crushing machines operate under conditions of an intensive wear. The data indicate

that 80 % of failures of machines and devices is caused by wearing of rubbing surfaces. This problem became the subject of several

scientific and industrial investigations carried out in the whole world in order to produce materials ultra- wear resistant. Methods allowing

to obtain wear resistant composite castings are discussed in the hereby paper. Within the performed research microstructures of the

produced composite zones were presented and the comparative analysis with regard to mechanical and functional properties of local

composite reinforcements in relation to the commercial alloys of increased wear resistance was performed. The results show almost twenty

five times increase in wear resistance compared to manganese cast steel containing 18 % Mn.

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The influence of the refractory coating which is a mixture of silica flour and kaolin on the surface roughness of the plate castings produced

using evaporative patterns had been considered in this work. The kaolin was used as a binder and ratio method was employed to form basis

for the factorial design of experiment which led to nine runs of experiments. Methyl alcohol at 99% concentration was used as the carrier

for the transfer of the coating to the surface of the patterns. Pouring temperature was observed as a process parameter alongside the mix

ratios of the coating. Attempts were made to characterize the refractory coating by using two methods; differential thermal analysis (DTA)

and X-ray diffraction. Attempt was also made to characterize the casting material. Gating system design was done for the plate casting to

determine the correct proportions of the gating parameters in order to construct the gating system properly to avoid turbulence during

pouring of liquid metal. A digital profilometer was used to take the measurements of the surface roughness. It was observed that the mix

ratio 90% silica flour-10% kaolin produced the lowest value of the surface roughness of the plate castings and had the lowest material loss

in the DTA test. The pouring temperature of 650o

C produced best casting.

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Heat treatment of a casting elements poured from silumins belongs to technological processes aimed mainly at change of their mechanical

properties in solid state, inducing predetermined structural changes, which are based on precipitation processes (structural strengthening of

the material), being a derivative of temperature and duration of solutioning and ageing operations. The subject-matter of this paper is the

issue concerning implementation of a heat treatment process, basing on selection of dispersion hardening parameters to assure

improvement of technological quality in terms of mechanical properties of a clamping element of energy network suspension, poured from

hypoeutectic silumin of the LM25 brand; performed on the basis of experimental research program with use of the ATD method, serving

to determination of temperature range of solutioning and ageing treatments. The heat treatment performed in laboratory conditions on a

component of energy network suspension has enabled increase of the tensile strength Rm and the hardness HB with about 60-70%

comparing to the casting without the heat treatment, when the casting was solutioned at temperature 520 o

C for 1 hour and aged at

temperature 165 o

C during 3 hours.

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The paper presents tribological properties of A390.0 (AlSi17Cu5Mg) alloy coupled in abrasive action with EN-GJL-350 grey cast-iron.

The silumin was prepared with the use of two different technologies which differed in terms of cooling speed. In the first case the alloy

was modified with foundry alloy CuP10 and cast to a standard tester ATD and in case of second option the modified alloy was cast into

steel casting die. Due to different speed of heat removal the silumins varied in structure, particularly with size of primary crystals of silicon

and their distribution in matrix which had a significant influence of friction coefficient in conditions of dry friction.

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The paper presents the use of rapid prototyping technology of three dimensional printing (3DP) to make a prototype shell casting mold. In

the first step, for identification purposes, a mold was prepared to enable different alloys to be cast. All molds being cast were designed in a

universal CAD environment and printed with the zp151 composite material (Calcium sulfate hemihydrate) with a zb63 binder (2-

pyrrolidone). It is designated to be used to prepare colourful models presenting prototypes or casting models and molds. The usefulness of

3DP technology for use with copper alloys, aluminum and zinc was analyzed. The strength of the mold during casting was assumed as a

characteristic comparative feature in the material resistance to high temperature, the quality of the resulting casting and its surface

roughness. Casting tests were carried out in vacuum – pressure casting. The casting programs applied, significantly increased the quality of

castings and enabled precise mold submergence. Significant improvement was noted in the quality compared to the same castings obtained

by gravity casting.

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In the paper, presented is a research on effectiveness of absorbing electromagnetic waves at frequency 2.45 GHz by unhardened moulding

sands prepared of three kinds of high-silica base and a selected grade of sodium silicate. Measurements of power loss of microwave

radiation (Pin) expressed by a total of absorbed power (Pabs), output power (Pout) and reflected power (Pref) were carried-out on a stand of

semiautomatic microwave slot line. Values of microwave power loss in the rectangular waveguide filled with unhardened moulding sands

served for determining effectiveness of microwave heating. Balance of microwave power loss is of technological and economical

importance for manufacture of high-quality casting moulds and cores of various shapes and sizes. It was found that relative density

influences parameters of power output and power reflected from samples of moulding sand placed in a waveguide. Absorption expressed

by the parameter Pabs is not related to granularity of high-silica base: fine, medium and coarse. It was found that the semiautomatic

microwave slot line supports evaluation of effectiveness of microwave absorption on the grounds of power loss measurements and enables

statistic description of influence of relative density of the sandmix on penetration of electromagnetic waves in unhardened moulding sands.

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This article presents the results of studies in the hypoeutectic silumin destined for pressure die casting with the simultaneous addition of

chromium and tungsten. The study involved the derivative and thermal analysis of the crystallization process, metallographic analysis and

mechanical properties testing. Silumin 226 grade was destined for studies. It is a typical silumin to pressure die casting. AlCr15 and AlW8

preliminary alloys were added to silumin. Its quantity allowed to obtain 0.1, 0.2, 0.3 and 0.4% of Cr and W in the tested alloy. Studies of

the crystallization process as well as the microstructure of the silumin poured into DTA sampler allowed to state the presence of additional

phase containing 0.2% or more Cr and W. It has not occurred in silumin without the addition of above mentioned elements. It is probably

the intermetallic phase containing Cr and W. DTA studies have shown this phase crystallizes at a higher temperature range than α (Al)

solid solution. In the microstructure of each pressure die casting containing Cr and W the new phases formed. Mechanical properties tests

have shown Cr and W additives in silumin in an appropriate amount may increase its tensile strength Rm (about 11%), the yield strength

Rp0.2 (about 21%) and to a small extent elongation A.

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Conducting reliable and credible evaluation and statistical interpretation of empirical results related to the operation of production systems

in foundries is for most managers complicated and labour-intensive. Additionally, in many cases, statistical evaluation is either ignored

and considered a necessary evil, or is completely useless because of improper selection of methods and subsequent misinterpretation of the

results. In this article, after discussing the key elements necessary for the proper selection of statistical methods, a wide spectrum of these

methods has been presented, including regression analysis, uni- and multivariate correlation, one-way analysis of variance for factorial

designs, and selected forecasting methods. Each statistical method has been illustrated with numerous examples related to the foundry

practice.

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This paper presents results of experimental research concerning the impact of an innovative method of micro-jet cooling on the padding

weld performed with MIG welding. Micro-jet cooling is a novel method patented in 2011. It enables to steer the parameters of weld

cooling in a precise manner. In addition, various elements which may e.g. enhance hardness or alter tribological properties can be entered

into its top surface, depending on the applied cooling gas. The material under study was steel 20MnCr5, which was subject to the welding

process with micro-jet cooling and without cooling. Nitrogen was used as a cooling gas. The main parameter of weld assessment was wear

intensity. The tests were conducted in a tribological pin-on-disc type position. The following results exhibit growth at approximately 5% in

wear resistance of padding welds with micro-jet cooling.

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The cooling rate is one of the main tools available to the process engineer by means of which it is possible to influence the crystallisation

process. Imposing a desired microstructure on a casting as early as in the casting solidification phase widens significantly the scope of

technological options at disposal in the process of aluminium-silicon alloy parts design and application. By changing the cooling rate it is

possible to influence the course of the crystallisation process and thus also the material properties of individual microstructure

components. In the study reported in this paper it has been found that the increase of cooling rate within the range of solidification

temperatures of a complex aluminium-silicon alloy resulted in a decrease of values of the instrumented indentation hardness (HIT) and the

instrumented indentation elastic modulus (EIT) characterising the intermetallic phase occurring in the form of polygons, rich in aluminium,

iron, silicon, manganese, and chromium, containing also copper, nickel, and vanadium. Increased cooling rate resulted in supersaturation

of the matrix with alloying elements.

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The paper deals with the effect of microstructure diversified by means of variable cooling rate on service properties of AlSi7Mg cast alloy

refined traditionally with Dursalit EG 281, grain refining with titanium-boron and modified with sodium and a variant of the same alloy

barbotage-refined with argon and simultaneously grain refining with titanium-boron and modified with strontium. For both alloy variants,

the castings were subject to T6 thermal treatment (solution heat treatment and artificial aging). It turned out that AlSi7Mg alloy after

simultaneous barbotage refining with argon and grain refining with titanium-boron and modified with strontium was characterised with

lower values of representative microstructure parameters (SDAS – secondary dendrite arm spacing, λE, lmax) and lower value of the

porosity ratio compared to the alloy refined traditionally with Dursalit EG 281 and grain refining with titanium-boron and modified with

sodium. The higher values of mechanical properties and fatigue strength parameters were obtained for the alloy simultaneously barbotagerefined

with argon and grain refining with titanium-boron and modified with strontium.

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The paper is a presentation of a study on issues concerning degradation of protective paint coat having an adverse impact on aesthetic

qualities of thin-walled cast-iron castings fabricated in furan resin sand. Microscopic examination and microanalyses of chemistry

indicated that under the coat of paint covering the surface of a thin-walled casting, layers of oxides could be found presence of which can

be most probably attributed to careless cleaning of the casting surface before the paint application process, as well as corrosion pits

evidencing existence of damp residues under the paint layers contributing to creation of corrosion micro-cells

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Automation of machining operations, being result of mass volume production of components, imposes more restrictive requirements

concerning mechanical properties of starting materials, inclusive of machinability mainly. In stage of preparation of material, the

machinability is influenced by such factors as chemical composition, structure, mechanical properties, plastic working and heat treatment,

as well as a factors present during machining operations, as machining type, cutting parameters, material and geometry of cutting tools,

stiffness of the system: workpiece – machine tool – fixture and cutting tool.

In the paper are presented investigations concerning machinability of the EN AC-AlSi9Cu3(Fe) silumin put to refining, modification and

heat treatment. As the parameter to describe starting condition of the alloy was used its tensile strength Rm. Measurement of the machining

properties of the investigated alloy was performed using a reboring method with measurement of cutting force, cutting torque and cutting

power. It has been determined an effect of the starting condition of the alloy on its machining properties in terms of the cutting power,

being indication of machinability of the investigated alloy. The best machining properties (minimal cutting power - Pc=48,3W) were

obtained for the refined alloy, without heat treatment, for which the tensile strength Rm=250 MPa. The worst machinability (maximal

cutting power Pc=89,0W) was obtained for the alloy after refining, solutioning at temperature 510 o

C for 1,5 hour and aged for 5 hours at

temperature 175 o

C. A further investigations should be connected with selection of optimal parameters of solutioning and ageing

treatments, and with their effect on the starting condition of the alloy in terms of improvement of both mechanical properties of the alloy

and its machining properties, taking into consideration obtained surface roughness.

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Some metallographic studies performed on the basis of the massive forging steel static ingot, on its cross-section, allowed to reveal the

following morphological zones: a/ columnar grains (treated as the austenite single crystals), b/ columnar into equiaxed grains

transformation, c/ equiaxed grains at the ingot axis. These zones are reproduced theoretically by the numerical simulation. The simulation

was based on the calculation of both temperature field in the solidifying large steel ingot and thermal gradient field obtained for the same

boundary conditions. The detailed analysis of the velocity of the liquidus isotherm movement shows that the zone of columnar grains

begins to disappear at the first point of inflection and the equiaxed grains are formed exclusively at the second point of inflection of the

analyzed curve. In the case of the continuously cast brass ingots three different morphologies are revealed: a/ columnar structure, b/

columnar and equiaxed structure with the CET, and c/ columnar structure with the single crystal formation at the ingot axis. Some

forecasts of the temperature field are proposed for these three revealed morphologies. An analysis / forecast of the behavior of the

operating point in the mold is delivered for the continuously cast ingot. A characteristic delay between some points of breakage of the

temperature profile recorded at the operating point and analogous phenomena in the solidifying alloy is postulated.

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The suspension of the copper droplets in the post-processing slag taken directly from the KGHM-Polska Miedź S.A. Factory (from the

direct-to-blister technology as performed in the flash furnace) was subjected to the special treatment with the use of the one of the typical

industrial reagent and with the complex reagent newly patented by the authors. This treatment was performed in the BOLMET S.A.

Company in the semi-industrial conditions. The result of the CaCO3, and Na2CO3 chemicals influence on the coagulation and subsequent

sedimentation of copper droplets on the crucible bottom were subjected to comparison with the sedimentation forced by the mentioned

complex reagent. The industrial chemicals promoted the agglomeration of copper droplets but the coagulation was arrested / blocked by

the formation of the lead envelope. Therefore, buoyancy force forced the motion of the partially coagulated copper droplets towards the

liquid slag surface rather than sedimentation on the crucible bottom. On the other hand, the complex reagent was able to influence the

mechanical equilibrium between copper droplets and some particles of the liquid slag as well as improve the slag viscosity. Finally, the

copper droplets coagulated successfully and generally, were subjected to a settlement on the crucible bottom as desired / requested.

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A356 is one of the widely used aluminium casting alloy that has been used in both sand and die casting processes. Large amounts of scrap

metal can be generated from the runner systems and feeders. In addition, chips are generated in the machined parts. The surface area with

regard to weight of chips is so high that it makes these scraps difficult to melt. Although there are several techniques evolved to remedy

this problem, yet the problem lies in the quality of the recycled raw material. Since recycling of these scrap is quite important due to the

advantages like energy saving and cost reduction in the final product, in this work, the recycling efficiency and casting quality were

investigated. Three types of charges were prepared for casting: %100 primary ingot, %100 scrap aluminium and fifty-fifty scrap

aluminium and primary ingot mixture were used. Melt quality was determined by calculating bifilm index by using reduced pressure test.

Tensile test samples were produced by casting both from sand and die moulds. Relationship between bifilm index and tensile strength were

determined as an indication of correlation of melt quality. It was found that untreated chips decrease the casting quality significantly.

Therefore, prior to charging the chips into the furnace for melting, a series of cleaning processes has to be used in order to achieve good

quality products.

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The main bulk density representation in the molding material is opening material, refractory granular material with a particle size of 0.02

mm. It forms a shell molds and cores, and therefore in addition to activating the surface of the grain is one of the most important features

angularity and particle size of grains. These last two features specify the porosity and therefore the permeability of the mixture, and

thermal dilatation of tension from braking dilation, the thermal conductivity of the mixture and even largely affect the strength of molds

and cores, and thus the surface quality of castings. [1]

Today foundries, which use the cast iron for produce of casts, are struggling with surface defects on the casts. One of these defects are

veining. They can be eliminated in several ways. Veining are foundry defects, which arise as a result of tensions generated at the interface

of the mold and metal. This tension also arises due to abrupt thermal expansion of silica sand and is therefore in the development of

veining on the surface of casts deal primarily influences and characteristics of the filler material – opening material in the production of

iron castings.

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Abstrakt

The paper presents an original method of measuring the actual chromite content in the circulating moulding sand of foundry. This type of

material is applied for production of moulds. This is the case of foundry which most frequently perform heavy casting in which for the

construction of chemical hardening mould is used, both the quartz sand and chromite sand. After the dry reclamation of used moulding

sand, both types of sands are mixed in various ratios resulting that in reclaimed sand silos, the layers of varying content of chromite in

mixture are observed. For chromite recuperation from the circulating moulding sand there are applied the appropriate installations

equipped with separate elements generating locally strong magnetic field. The knowledge of the current ratio of chromite and quartz sand

allows to optimize the settings of installation and control of the separation efficiency. The arduous and time-consuming method of

determining the content of chromite using bromoform liquid requires operational powers and precautions during using this toxic liquid.

It was developed and tested the new, uncomplicated gravimetric laboratory method using powerful permanent magnets (neodymium).

The method is used in the production conditions of casting for current inspection of chromite quantity in used sand in reclamation plant.

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To improve mechanical properties and increasing useful life of metal pieces, different methods of welding are used for repairing surface

crack of metal pieces. In this research, performance of flame welding method by spraying pure iron powder evaluated for repairing surface

grooves of structural steel. First, four specimens including one control specimen and other three specimens grooved specimens in depth of

1mm and in length of 12.5mm and groove width in the sizes of 0.5, 0.75 and 1mm.were prepared then, powder melted using oxyacetylene

reducing flame and spraying iron powder in the flame path and attached to the inner surface of the groove and finally, the specimen

repaired. Results showed that after repairing surface groove, tensile strength of the repaired specimens were reached to the tensile strength

of control specimen with the margin of 2.5%.

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Abstrakt

The near net shaped manufacturing ability of squeeze casting process requiresto set the process variable combinations at their optimal

levels to obtain both aesthetic appearance and internal soundness of the cast parts. The aesthetic and internal soundness of cast parts deal

with surface roughness and tensile strength those can readily put the part in service without the requirement of costly secondary

manufacturing processes (like polishing, shot blasting, plating, hear treatment etc.). It is difficult to determine the levels of the process

variable (that is, pressure duration, squeeze pressure, pouring temperature and die temperature) combinations for extreme values of the

responses (that is, surface roughness, yield strength and ultimate tensile strength) due to conflicting requirements. In the present

manuscript, three population based search and optimization methods, namely genetic algorithm (GA), particle swarm optimization (PSO)

and multi-objective particle swarm optimization based on crowding distance (MOPSO-CD) methods have been used to optimize multiple

outputs simultaneously. Further, validation test has been conducted for the optimal casting conditions suggested by GA, PSO and

MOPSO-CD. The results showed that PSO outperformed GA with regard to computation time.

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Redakcja

CHIEF EDITORS
Editor
J. Szajnar
Deputy Editor
J. Jezierski

SUBJECT EDITORS
Theoretical Aspects of Casting Processes
K. Eigenfeld – Freiberg, Germany
E. Guzik – Kraków, Poland
T. G. Mathia - Lyon, France
W. Wołczyński – Kraków, Poland
Innovative Foundry Technologies and Materials
T. Elbel – Ostrava, Czech Republic
Z. Ignaszak – Poznań, Poland
O. P. Pandey – Punjab, India
A. Pereira - Vigo, Spain
Foundry Processes Computer Aiding
B. Mochnacki – Częstochowa, Poland
J. Roučka – Brno, Czech Republic
J.S. Suchy – Kraków, Poland
Mechanization, Automation and Robotics in Foundry
J. Bast – Freiberg, Germany
R. Wrona – Kraków, Poland
Transport Systems in Foundry
J. Dańko – Kraków, Poland
Z. Li – Shijiazhuang, China
Castings Quality Management
D. Bolibruchova– Żilina, Slovak Republic
J. D. B. de Mello - Santa Monica, Brazil
M. Perzyk – Warszawa, Poland
Environment Protection
M. Holtzer – Kraków, Poland
H. Polzin – Freiberg, Germany
J. Sobczak – Kraków, Poland
I. Volchok – Zaporizhzhya, Ukraine

EDITORIAL ADVISORY BOARD
J. Braszczyński – Częstochowa, Poland
B. K. Dhindaw – Rupnagar, India
L. A. Dobrzański – Gliwice, Poland
W. A. Hufenbach – Dresden, Germany
P. Jelínek – Ostrava, Czech Republic
L. Jeziorski – Częstochowa, Poland
J. Lacaze – Toulouse, France
V. L. Naydek – Kiev, Ukraine
A. Passerone – Genova, Italy
I. Riposan – Bucharest, Romania
F. Romankiewicz – Zielona Góra, Poland
A. Sládek – Żilina, Slovak Republic

INTERNATIONAL SCIENTIFIC REVIEW COMMITTEE
S. A. Argyropoulos – Toronto, Canada
M. Azadi – Tehran, Iran
Y. Babaskin – Kiev, Ukraine
K. Bako – Miskolc, Hungary
E. Bayraktar – Paris, France
L. Bechný – Zilina, Slovak Republic
V. Bednarova - Ostrava, Czech Republic
F. Bińczyk – Katowice, Poland
A. Bokota – Częstochowa, Poland
G.P. Borisov – Kiev, Ukraine
A. Bydałek – Kraków, Poland
C. H. Cáceres – Brisbane, Australia
J. Čech – Brno, Czech Republic
L. Q. Chen – Shenyang, China
A. Chojecki – Kraków, Poland
M. Cholewa – Gliwice, Poland
I. A. Dibrov – Moscow, Russia
D. Dispinar – Istanbul, Turkey
S. M. Dobosz – Kraków, Poland
V. I. Dubodelov – Kiev, Ukraine
A. Fedoryszyn – Krakow, Poland
J. Głownia – Kraków, Poland
K. Granat – Wrocław, Poland
J. Hampl – Ostrava, Czech Republic
J. Helber – Düsseldorf, Germany
M. Hetmańczyk – Katowice, Poland
M. Horáček – Brno, Czech Republic
M. Kaczorowski – Warszawa, Poland
W. Kapturkiewicz – Kraków, Poland
R. Kawalla – Freiberg, Germany
Z. Konopka – Czestochowa, Poland
D. Kopyciński – Kraków, Poland
W. K. Krajewski – Kraków, Poland
Z. Libo – Beijing, China
P. Lichy – Ostrava, Czech Republic
Y. P. Lim – Setapak, Malaysia
T. Lipiński – Olsztyn, Poland
E. Majchrzak – Gliwice, Poland
A. Mityayev - Zaporizhzhya, Ukraine
M. Murgaš – Trnava, Slovak Republic
I. Nová – Liberec, Czech Republic
W. Orłowicz – Rzeszów, Poland
T. Pacyniak – Łódź, Poland
B. Piekarski – Szczecin, Poland
A. Rimmer – West Bromwich, United Kingdom
S. Samavedam – Hyderabad, India
P. Schumacher – Leoben, Austria
N. Sczygiol – Częstochowa, Poland
P. Skočovský – Żilina, Slovak Republic
M.S. Soiński – Częstochowa, Poland
J. Sokolowski – Ottawa, Kanada
K. V. Sudhakar – Butte, USA
B. G. Thomas - Champaign, USA
M. Trbižan – Ljubljana, Slovenia
J. Vuorinen – Tampere, Finland
E. Ziółkowski – Kraków, Poland
J. Zych – Kraków, Poland

ASSOCIATE EDITORS
D. Bartocha – Gliwice, Poland, - editorial secretary
J. Suchoń – Gliwice, Poland - editorial secretary
J. Szymszal – Katowice, Poland, Statistic Editor
A. Dulska – Gliwice, Poland
M. Kondracki – Gliwice, Poland
C. Borek –Chicago, USA, Language Editor

 

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