Archives of Foundry Engineering

Porosity is one of the major defects in aluminum castings, which results is a decrease of a mechanical properties. Porosity in aluminum alloys is caused by solidification shrinkage and gas segregation. The final amount of porosity in aluminium castings is mostly influenced by several factors, as amount of hydrogen in molten aluminium alloy, cooling rate, melt temperature, mold material, or solidification interval. This article deals with effect of chemical composition on porosity in Al-Si aluminum alloys. For experiment was used Pure aluminum and four alloys: AlSi6Cu4, AlSi7Mg0, 3, AlSi9Cu1, AlSi10MgCu1.

This paper deals with influence of chrome addition and heat treatment on segregation of iron based phases in the secondary alloy

AlSi7Mg0.3 microstructure by chrome and heat treatment. Iron is the most common and harmful impurity in aluminum casting alloys and

has long been associated with an increase of casting defects. In generally, iron is associated with the formation of Fe-rich intermetallic

phases. It is impossible to remove iron from melt by standard operations, but it is possible to eliminate its negative influence by addition

some other elements that affect the segregation of intermetallics in less harmful type or by heat treatment. Realization of experiments and

results of analysis show new view on solubility of iron based phases during melt preparation with higher iron content and influence of

chrome as iron corrector of iron based phases.

This paper deals with the evaluation of the corrosion resistance of the Al-Si alloys alloyed with the different amount of antimony.

Specifically it goes about the alloy AlSi7Mg0,3 which is antimony alloyed in the concentrations 0; 0,001; 0,005; 0,01 a 0,05 wt. % of

antimony. The introduction of the paper is dedicated to the theory of the aluminium alloys corrosion resistance, testing and evaluation of

the corrosion resistance. The influence of the antimony to the Al-Si alloys properties is described further in the introduction. The

experimental part describes the experimental samples which were prepared for the experiment and further they were exposed to the

loading in the atmospheric conditions for a period of the 3 months. The experimental samples were evaluated macroscopically and

microscopically. The results of the experiment were documented and the conclusions in terms of the antimony impact to the corrosion

resistance of the Al-Si alloy were concluded. There was compared the corrosion resistance of the Al-Si alloy antimony alloyed (with the

different antimony content) with the results of the Al-Si alloy without the alloying after the corrosion load in the atmospheric conditions in

the experiment.

The work deals with the influence of change in the filling conditions of the ceramic moulds with plaster binder on the presence of gaseous

porosity and the microstructure of the achieved test castings with graded wall thickness. Castings made of EN AC-44000 alloy, produced

either by gravity casting, or by gravity casting with negative pressure generated around the mould (according to the Vacumetal

technology), or by counter-gravity casting were compared. The results of examinations concerning the density of the produced castings

indicate that no significant change in porosity was found. The increased size of silicon crystals was found for the increased wall

thicknesses due to the slower cooling and solidification of castings.

The presented work is aimed to deal with the influence of changes in the value of negative (relative) pressure maintained in the die

cavity of pressure die casting machine on the surface quality of pressure castings. The examinations were held by means of the

modified Vertacast pressure die casting machine equipped with a vacuum system. Castings were produced for the parameters selected

on the basis of previous experiments, i.e. for the plunger velocity in the second stage of injection at the level of 4 m/s, the pouring

temperature of the alloy equal to 640°C, and the die temperature of 150°C. The examinations were carried on for three selected values

of negative gauge pressure: - 0.03, - 0.05, and - 0.07 MPa. The quality of casting was evaluated by comparing the results of the surface

roughness measurements performed for randomly selected castings. The surface roughness was measured by means of Hommel Tester

T1000. After a series of measurements it was found that the smoothest surface is exhibited by castings produced at negative gauge

pressure value of - 0.07 MPa.

Improvement of Al-Si alloys properties in scope of classic method is connected with change of Si precipitations morphology through:

using modification of the alloy, maintaining suitable temperature of overheating and pouring process, as well as perfection of heat

treatment methods. Growing requirements of the market make it necessary to search after such procedures, which would quickly deliver

positive results with simultaneous consideration of economic aspects. Presented in the paper shortened heat treatment with soaking of the

alloy at temperature near temperature of solidus could be assumed as the method in the above mentioned understanding of the problem.

Such treatment consists in soaking of the alloy to temperature of solutioning, keeping in such temperature, and next, quick quenching in

water (20 0

C) followed by artificial ageing. Temperature ranges of solutioning and ageing treatments implemented in the adopted testing

plan were based on analysis of recorded curves from the ATD method. Obtained results relate to dependencies and spatial diagrams

describing effect of parameters of the solutioning and ageing treatments on HB hardness of the investigated alloy and change of its

microstructure. Performed shortened heat treatment results in precipitation hardening of the investigated 320.0 alloy, what according to

expectations produces increased hardness of the material.

The work presents the investigation results concerning the structure of composite pressure die castings with AlSi11 alloy matrix reinforced

with SiC particles. Examination has been held for composites containing 10 and 20 volume percent of SiC particles. The arrangement of

the reinforcing particles within the matrix has been qualitatively assessed in specimens cut out of the castings. The index of distribution

was determined on the basis of particle count in elementary measuring fields. The tensile strength, the yield point and elongation of the

obtained composite were measured. Composite 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. The regression equation describing the change of

the considered arrangement particles index and mechanical properties were found as a function of the pressure die casting parameters. The

infuence of particle arrangement in composite matrix on mechanical properties these material was examined and the functions of

correlations between values were obtained. The conclusion gives the analysis and the interpretation of the obtained results.

The results of experimental study of solid state joining of tungsten heavy alloy (THA) with AlMg3Mn alloy are presented. The aim of

these investigations was to study the mechanism of joining two extremely different materials used for military applications. The

continuous rotary friction welding method was used in the experiment. The parameters of friction welding process i.e. friction load and

friction time in whole studies were changed in the range 10 to 30kN and 0,5 to 10s respectively while forging load and time were constant

and equals 50kN and 5s. The results presented here concerns only a small part whole studies which were described elsewhere. These are

focused on the mechanism of joining which can be adhesive or diffusion controlled. The experiment included macro- and microstructure

observations which were supplemented with SEM investigations. The goal of the last one was to reveal the character of fracture surface

after tensile test and to looking for anticipated diffusion of aluminum into THA matrix. The results showed that joining of THA with

AlMg2Mn alloy has mainly adhesive character, although the diffusion cannot be excluded.

Contemporary materials engineering requires the use of materials characterised by high mechanical properties, as these precisely

properties determine the choice of material for parts of machinery and equipment. Owing to these properties it is possible to reduce

the weight and, consequently, the consumption of both material and energy. Trying to meet these expectations, the designers are

increasingly looking for solutions in the application of magnesium alloys as materials offering a very beneficial strength-to-weight ratio.

However, besides alloying elements, the properties are to a great extent shaped by the solidification conditions and related structure.

The process of structure formation depends on the choice of casting method forced by the specific properties of casting or by the specific

intended use of final product. The article presents a comparison of AZ91 magnesium alloys processed by different casting technologies.

A short characteristic was offered for materials processed by the traditional semi-continuous casting process, which uses the solidification

rates comprised in a range of 5 - 20⁰C/s, and for materials made in the process of Rapid Solidification, where the solidification rate can

reach 106 ⁰C/s. As a result of the casting process, a feedstock in the form of billets and thin strips was obtained and was subjected next

to the process of plastic forming. The article presents the results of structural analysis of the final product. The mechanical properties

of the ø7 mm extruded rods were also evaluated and compared.

Experimental Mg-Al-RE type magnesium alloys for high-pressure die-casting are presented. Alloys based on the commercial AM50

magnesium alloy with 1, 3 and 5 mass % of rare earth elements were fabricated in a foundry and cast in cold chamber die-casting

machines. The obtained experimental casts have good quality surfaces and microstructure consisting of an α(Mg)-phase, Al11RE3,

Al10RE2Mn7 intermetallic compound and small amount of α+γ eutectic and Al2RE phases.

The results of examinations of the influence of titanium-boron inoculant on the solidification, the microstructure, and the mechanical

properties of AlZn20 alloy are presented. The examinations were carried out for specimens cast both of the non-modified and the

inoculated alloy. There were assessed changes in the alloy overcooling during the first stage of solidification due to the nuclei-forming

influence of the inoculant. The results of quantitative metallographic measurements concerning the refinement of the grain structure of

casting produced in sand moulds are presented. The cooling rate sensitivity of the alloy was proved by revealing changes in morphology of

the α-phase primary crystals. Differences in mechanical properties resulting from the applied casting method and optional inoculation were

evaluated.

In the aluminium alloy family, Al-Zn materials with non-standard chemical composition containing Mg and Cu are a new group

of alloys, mainly owing to their high strength properties. Proper choice of alloying elements, and of the method of molten metal treatment

and casting enable further shaping of the properties. One of the modern methods to produce materials with submicron structure is a method

of Rapid Solidification. The ribbon cast in a melt spinning device is an intermediate product for further plastic working. Using the

technique of Rapid Solidification it is not possible to directly produce a solid structural material of the required shape and length.

Therefore, the ribbon of an ultrafine grain or nanometric structure must be subjected to the operations of fragmentation, compaction,

consolidation and hot extrusion.

In this article the authors focussed their attention on the technological aspect of the above mentioned process and described successive

stages of the fabrication of an AlZn9Mg2.5Cu1.8 alloy of ultrafine grain structure designated for further plastic working, which enables

making extruded rods or elements shaped by the die forging technology. Studies described in the article were performed under variable

parameters determined experimentally in the course of the alloy manufacturing process, including casting by RS and subsequent

fragmentation.

In the course of homogenizing annealing of aluminium alloys being cast continually or semi-continually it appears that chemical

inhomogenity takes off within separate dendritic cells (crystal segregation). It is about a diffusion process that takes place at the

temperature which approaches the liquid temperature of the material. In that process the transition of soluble intermetallic compounds and

eutectic to solid solution occurs and it suppresses crystal segregation significantly [1]. The temperature, homogenization time, the size of

dendritic cells and diffusion length influences homogenizing process. The article explores the optimization of homogenizing process in

terms of its time and homogenizing annealing temperature which influence mechanical properties of AlZn5,5Mg2,5Cu1,5 alloy.

The article describes the problem of selection of heat treatment parameters to obtain the required mechanical properties in heat- treated

bronzes. A methodology for the construction of a classification model based on rough set theory is presented. A model of this type allows

the construction of inference rules also in the case when our knowledge of the existing phenomena is incomplete, and this is situation

commonly encountered when new materials enter the market. In the case of new test materials, such as the grade of bronze described in

this article, we still lack full knowledge and the choice of heat treatment parameters is based on a fragmentary knowledge resulting from

experimental studies. The measurement results can be useful in building of a model, this model, however, cannot be deterministic, but can

only approximate the stochastic nature of phenomena. The use of rough set theory allows for efficient inference also in areas that are not

yet fully explored.

The article presents research results performed on aluminum bronze CuAl10Fe5Ni5 (BA1055) castings used for marine propellers.

Metallographic studies were made on light microscope and a scanning electron microscope to assess quantitatively and qualitatively the

alloy microstructure. It has been shown that the shape, size and distribution of the iron-rich κ−phase precipitates in bronze microstructure

significantly affect its mechanical properties. With an increase in the number of small κ−phase precipitates increases the tensile strength of

castings, while the presence of large globular precipitates improves ductility. Fragmentation and shape of κ−phase precipitates depends on

many factors, particularly on the chemical composition of the alloy, Fe/Ni ratio, cooling rate and casting technology.

The work presents experiment results from the area of copper casting technology and chosen examples of alloyed copper. At present,

copper casting technology is applied in many branches of industrial manufacturing, especially in the sector of construction,

communications, arms and power engineering. Alloyed copper, containing slight additions of different elements and having special

physio-chemical properties, is used in a special range of applications. Copper technology and alloyed copper analyses have been presented,

these materials being used for cast manufacturing for power engineering. The quality of casts has been assessed, based on their

microstructure analysis, chemical content and the cast properties. During the research, special deoxidizing and modifying agents were

applied for copper and chosen examples of alloyed copper; also exemplary samples were tested with the help of metallographic analysis,

electrical conductivity and gaseous impurities research.

The aim of this work is the development of Cu-Al2O3 composites of copper Cu-ETP matrix composite materials reinforced by 20 and 30

vol.% Al2O3 particles and study of some chosen physical properties. Squeeze casting technique of porous compacts with liquid copper

was applied at the pressure of 110 MPa. Introduction of alumina particles into copper matrix affected on the significant increase of

hardness and in the case of Cu-30 vol. % of alumina particles to 128 HBW. Electrical resistivity was strongly affected by the ceramic

alumina particles and addition of 20 vol. % of particles caused diminishing of electrical conductivity to 20 S/m (34.5% IACS). Thermal

conductivity tests were performed applying two methods and it was ascertained that this parameter strongly depends on the ceramic

particles content, diminishing it to 100 Wm-1K-1 for the composite material containing 30 vol.% of ceramic particles comparing to 400

Wm-1K-1 for the unreinforced copper. Microstructural analysis was carried out using SEM microscopy and indicates that Al2O3 particles

are homogeneously distributed in the copper matrix. EDS analysis shows remains of silicon on the surface of ceramic particles after

binding agent used during preparation of ceramic preforms.

The results presented in this paper are a continuation of the previously published studies. The results of hest treatment of ductile iron with

content 3,66%Si and 3,80% Si were produced. The experimental castings were subjected to austempering process for time 30, 60 and 90

minutes at temperature 300o

C. The mechanical properties of heat treated specimens were studied using tensile testing and hardness

measurement, while microstructures were evaluated with conventional metallographic observations. It was again stated that austempering

of high silicone ferritic matrix ductile iron allowed producing ADI-type cast iron with mechanical properties comparable with standard

ADI.

The work determined the influence of aluminium in the amount from about 0.6% to about 8% on graphitization of cast iron with

relatively high silicon content (3.4%-3.9%) and low manganese content (about 0.1%). The cast iron was spheroidized with cerium mixture

and graphitized with ferrosilicon. It was found that the degree of graphitization increases with an increase in aluminium content in cast

iron up to 2.8%, then decreases. Nodular and vermicular graphite precipitates were found after the applied treatment in cast iron containing

aluminium in the amount from about 1.9% to about 8%. The Fe3AlCx carbides, increasing brittleness and deteriorating the machinability of

cast iron, were not found in cast iron containing up to about 6.8% Al. These carbides were revealed only in cast iron containing about 8% Al.

Development of salt cores prepared by high-pressure squeezing and shooting with inorganic binders has shown a high potential of the

given technology even for high-pressure casting of castings. Strength, surface quality of achieved castings, and solubility in water become

a decisive criterion. The shape and quality of grain surface particularly of NaCl – cooking salts that can be well applied without anticaking

additives has shown to be an important criterion. Thus the salt cores technology can cover increasingly growing demands for casting

complexity especially for the automobile industry.

Presented are results of a research on usability of an innovative reclamation process of microwave-hardened moulding sands containing

water-glass, combined with activation of binder. After each subsequent stage of reclamation, quality of the reclaimed material was

determined on the grounds of measurements of permeability and results of screen analysis. The reclaimed material was next used again to

prepare new moulding sand. The sandmix based on high-silica sand prepared with water-glass grade 145, was subject to the following

cyclical treatment operations: mixing components, consolidation, microwave hardening, cooling, heating the mould up to 800 °C, cooling

to ambient temperature, mechanical reclamation dry and wet. It was found that the used-up and reclaimed sandmix containing water-glass

is susceptible to the applied activation process of thermally reacted film of binder and, in addition, it maintains good quality and

technological properties of high-silica base. Observations of surfaces of reclaimed high-silica grains with activated film of reacted

inorganic binder were carried-out using a scanning microscope. Thanks to properly selected reclamation parameters, the high-silica base

can be reused even five times, thus reducing demand for fresh aggregate and inorganic binder.

In the paper presented are results of a research on influence of electrical and physico-chemical properties of materials being parts of

multicomponent and multimaterial systems used in foundry practice on efficiency and effectiveness of microwave heating. Effectiveness

of the process was evaluated on the grounds of analysis of interaction between selected parameters of permittivity and loss factor, as well

as collective index of energy absorbed, reflected and transmitted by these materials. In the examinations used was a stand of waveguide

resonance cavity for determining electrical properties and a stand of microwave slot line for determining balance of microwave power

emitted into selected materials. The examinations have brought closer the possibility of forecasting the behaviour of multimaterial systems

like e.g. model, moulding sand or moulding box in microwave field on the grounds of various electrical and physico-chemical properties.

On the grounds of analysis of the results, possible was selecting a group of materials designed for building foundry instrumentation to be

effectively used in electromagnetic field.

The present article deals with the possibility of using the reverse engineering method for the production of prototype molds by Patternless

process technology. Article describes method how to obtain virtual model by using a 3D scanner. Article also explains principle of the

Patternless process technology, which is based on the milling mold cavity using CNC machining equipment. The aim of the research is the

use of advanced technologies that speed up and facilitate the process of production prototype mold. The practical result of the presented

experiment is bronze casting, which serves as a foot rest bracket on historic bike.

Contribution gives an overview of knowledge about the method of centrifugal casting with orientate on Tekcast system. Company Tekcast

Industries has developed a device for centrifugal casting, extending the area of production of castings or prototyping of metal or plastic.

Materials suitable for the centrifugal casting with flexible operating parameters may include non-ferrous metal alloy based on zinc or

aluminum or non-metallic materials such as polyester resins, polyurethane resins, epoxy resins, waxes and the like. The casting process is

particularly suitable for a wide range of commercial castings and decorative objects.

Bentonite is clay rock, which is created by decomposition of vulcanic glass. It is formed from mixture of clay minerals of smectite group,

mainly montmorillonite, beidellite and nontronite. Its typical characteristics is, that when in contact with water, it intensively swells. First

who used this term was W.C. Knight in 1887. The rock had been named after town Fort Benton in American state Montana. For its

interesting technological properties and whiteness has wide technological use. Bentonite is selectively mined and according to its final use

separately modified, which results in high quality product with specific parameters.

In the beginning of 21st century belong bentonite moulding mixtures in foundry to always perspective. Mainly increased ratio of ductile

cast iron castings production cannot be ensured without the need of quality bentonite. Great area of scope remains to further research of

moulding materials, which return also to bentonite producers.