Wyniki wyszukiwania - BazTech

1

Investment Casting of AZ91 Magnesium Open-Cell Foams

Kapłon Honorata, Dmitruk Anna, Naplocha Krzysztof

Archives of Foundry Engineering

|

2023

|

Vol. 23, iss. 1

11--16

EN

The process of investment casting of AZ91 magnesium alloy open-cell porosity foams was analysed. A basic investment casting technique was modified to enable the manufacturing of magnesium foams of chosen porosities in a safe and effective way. Various casting parameters (mould temperature, metal pouring temperature, pressure during metal pouring and solidifying) were calculated and analysed to assure complete mould filling and to minimize surface reactions with mould material. The foams manufactured with this method have been tested for their mechanical strength and collapsing behaviour. The AZ91 foams acquired in this research turned out to have very high open porosity level (>80%) and performed with Young’s modulus of ~30 MPa on average. Their collapsing mechanism has turned out to be mostly brittle. Magnesium alloy foams of such morphology may find their application in fields requiring lightweight materials of high strength to density ratio or of high energy absorption properties, as well as in biomedical implants due to magnesium’s high biocompatibility and its mechanical properties similar to bone tissue.

2

Effect of Alloying Additives and Casting Parameters on the Microstructure and Mechanical Properties of Silicon Bronzes

Witasiak Dawid, Garbacz-Klempka Aldona, Papaj M., Papaj P., Piękoś Marcin, Kozana Janusz, Maj Maria, Peret-Nowak Małgorzata

Archives of Foundry Engineering

|

2023

|

Vol. 23, iss. 3

110--117

EN

The studied silicon bronze (CuSi3Zn3Mn1) is characterised by good strength and corrosion resistance due to the alloying elements that are present in it (Si, Zn, Mn, Fe). This study analysed the casting process in green sand moulding, gravity die casting, and centrifugal casting with a horizontal axis of rotation. The influences of Ni and Zr alloying additives as well as the casting technology that was used were evaluated on the alloy’s microstructure and mechanical properties. The results of the conducted research are presented in the form of the influence of the technology (GS, GZ, GM) and the content of the introduced alloy additives on the mechanical parameters (UTS, A10, and Proof Stress, BHN). The analysis of the tests that were carried out made it possible to determine which of the studied casting technologies had the best mechanical properties. Microstructure of metal poured into metal mould was finer than that which was cast into moulding compound. Mechanical properties of castings made in moulding compound were lower than those that were cast into metal moulds. Increased nickel content affected the BHN parameter.

3

Assessment of Foundry Chromite Sand Crushability under Thermal-Mechanical Loading

Kabasele Jonathan K., Nyembwe Kasongo D., Polzin H.

Archives of Foundry Engineering

|

2023

|

Vol. 23, iss. 3

16--21

EN

When used for sand casting, foundry sand is stressed in several ways. These stresses, thermal and mechanical, compromise the grain integrity, resulting in size reduction and the production of small particles to the point where the sand is no longer viable for sand casting. This study evaluates the crushability of chromite sand, a crucial characteristic for determining how resistant sand is to size reduction by crushing. To replicate the heat and mechanical strain that sand is subjected to during the industrial sand-casting process, a sinter furnace and rod mill were employed. After nine minutes of heat and mechanical stress application, the crushing ratio, which was used to gauge the crushability of chromite sand, ranged from 1.72 to 1.92 for all samples. There were differences in the rate at which fine particles were produced among the samples, with sample E producing the highest proportion of fine particles in the same length of time. Understanding the properties that control the crushability performance of chromite sand will enable foundries to buy chromite sand with higher recycling yield, reducing the environmental impact of waste foundry sand and eliminating the risk to the workforce's pulmonary health in line with the current industry standards. Foundries will also be able to optimize the current industrial process while continually pushing for innovative foundry technologies and materials.

4

Mechanical and Thermal Properties of Aluminum Foams Manufactured by Investment Casting Method

Dmitruk Anna, Kapłon H., Naplocha K.

Archives of Foundry Engineering

|

2022

|

Vol. 22, iss. 1

37--42

EN

A method for the open-cell aluminum foams manufacturing by investment casting was presented. Among mechanical properties, compressive behaviour was investigated. The thermal performance of the fabricated foams used as heat transfer enhancers in the heat accumulator based on phase change material (paraffin) was studied during charging-discharging working cycles in terms of temperature distribution. The influence of the foam on the thermal conductivity of the system was examined, revealing a two-fold increase in comparison to the pure PCM. The proposed castings were subjected to cyclic stresses during PCM’s subsequent contraction and expansion, while any casting defects present in the structure may deteriorate their durability. The manufactured heat transfers enhancers were found suitable for up to several dozen of cycles. The applied solution helped to facilitate the heat transfer resulting in more homogeneous temperature distribution and reduction of the charging period’s duration.

5

Evaluation of Wear Mechanisms of Graphites Used for Crystallisers for Continuous Casting

Brudny Anna, Kulasa Joanna, Juszczyk Barbara, Myalski Jerzy, Roskosz Stanisław, Wycisk R., Kwaśniewski Paweł, Strzępek Paweł, Poręba Marek

Archives of Foundry Engineering

|

2022

|

Vol. 22, iss. 4

109--115

EN

This paper presents the results of research concerning the evaluation of tribological properties of graphite materials used, among others, for crystallisers for continuous casting of non-ferrous metals and their alloys. Graphite materials differing not only in their physical properties but also in the technology of their production were selected from a wide range of commercially available products. Wear resistance investigations of the tested graphite materials were carried out on a pin-on-disc tribometer under technically dry friction conditions on a sliding distance of 1000 m. A constant load but variable speed was used in the tests. The mean value of the coefficient of friction and the wear of the material were determined based on the tribological tests carried out. It was observed that as the speed increases, the average value of the coefficient of friction decreases, while the wear increases. A microstructural analysis of the wear track showed that the friction mechanism depends mainly on the graphite formation technology, which is related to the microstructure of the tested materials, and to a lesser extent to their physical and mechanical properties. Varying the speed values made it possible to trace changes in the wear mechanism, on the basis of which it is possible to predict the durability and reliability of graphite crystalliser operation.

6

Research on Assessment of the Applicability of Malted Barley Binder in Moulding Sand Technology

Samociuk Bartłomiej, Gal B., Nowak D.

Archives of Foundry Engineering

|

2021

|

Vol. 21, iss. 1

74--80

EN

The foundry industry is looking for solutions that improve the quality of the finished product and solutions that reduce the negative impact of the industry on the natural environment [26]. This process leads to work on the use of new or previously unused materials for binders. Organic and inorganic foundry binders are replaced by renewable materials of plant origin to meet the requirements of both the foundry customers and the environmental and health and safety regulations. The aim of this work was to identify the applicability of renewable and organic malted barley binder in moulding sand technology. The influence of the malt binder content on dry tensile strength, dry bending strength, dry permeability, dry wear resistance and flowability were evaluated. The results show that the malted barley binder can be self contained material binding the high-silica sand grains. Selected mechanical properties of moulding sands were found to increase with an increase in binder content. It was observed that malted barley binder creates smooth bonding bridges between high-silica sand grains.

7

Integration of Virtual Engineering and Additive Manufacturing for Rapid Prototyping of Precision Castings

Krutiš V., Šprta P., Kaňa V., Zadera A., Cileček J.

Archives of Foundry Engineering

|

2021

|

Vol. 21, iss. 1

51--55

EN

The present paper is concerned with the practical interconnection between virtual engineering tools and additive model manufacturing technologies and the subsequent production of a ceramic shell by rapid prototyping with the use of Cyclone technology to produce the aluminium casting prototype. Prototypes were developed as part of the student formula project, where several parts originally produced by machining were replaced by castings. The techniques of topological optimization and the combination with the tools of the numerical simulation were used to optimise the virtual prototype before a real production of the first prototype. 3D printing of wax pattern ensured direct and fast assembly of the cluster without any additional operations and troubles during dewaxing. The shell was manufactured in 6 hours thanks to a system of quick-drying of individual layers of ceramic shell. It has been verified that the right combination of individual virtual tools with the rapid prototyping can shorten the development time and delivery of the first prototypes from a few months to a few weeks.

8

Using of Technology Semisolid Squeeze Casting by Different Initial States of Material

Martinec D., Pastirčák R., Kantoríková E.

Archives of Foundry Engineering

|

2020

|

Vol. 20, iss. 1

117--121

EN

The paper deals with the effect of heating of various prepared batch materials into semisolid state with subsequent solidification of the cast under pressure. The investigated material was a subeutectic aluminium alloy AlSi7Mg0.3. The heating temperature to the semisolid was chosen at 50% liquid phase. The used material was prepared in a variety of ways: heat treatment, inoculation and by squeeze casting. Also the influence of the initial state of material on inheritance of mechanical properties and microstructure was observed. The pressure was 100 MPa. Effect on the resulting casting structure, alpha phase distribution and eutectic silicon was observed. By using semisolid squeeze casting process the mechanical properties and microstructures of the casts has changed. The final microstructure of the casts is very similar to the microstructure that can be reached by technology of thixocasting. The mechanical properties by using semisolid squeeze casting has been increased except the heat treated material.

9

The Effect of Bifilm and Sr Modification on the Mechanical Properties of AlSi12Fe Alloy

Uludağ M., Gurtaran M., Dispinar D.

Archives of Foundry Engineering

|

2020

|

Vol. 20, iss. 3

99--104

EN

The microstructure of Al-Si alloy has coarse silicon and this structure is known dangerous for mechanical properties due to its crack effect. Sr addition is preferred to modify the coarse silica during solidification. Additionally, bifilms (oxide structure) are known as a more dangerous defect which is frequently seen in light alloys. It is aimed at that negative effect of bifilms on the properties of the alloys tried to be removed by the degassing process and to regulate the microstructure of the alloy. In this study, the effect of degassing and Sr modification on the mechanical properties of AlSi12Fe alloy was investigated, extensively. Four different parameters (as-received, as-received + degassing, Sr addition, Sr addition + degassing) were studied under the same conditions environmentally. The microstructural analyses and mechanical tests were done on cast parts. All data obtained from the experimental study were analyzed statistically by using statistical analysis software. It was concluded from the results that Sr addition is very dangerous for AlSi12Fe alloy. It can be suggested that to reach high mechanical properties and low casting defects, the degassing process must be applied to all castings whereas Sr addition should not be preferred.

10

Influence of Sand Fluidization on Structure and Properties of Aluminum Lost Foam Casting

Kaliuzhnyi P.

Archives of Foundry Engineering

|

2020

|

Vol. 20, iss. 1

122--126

EN

The article presents investigation results of the effect of sand fluidization on the structure and mechanical properties of AlSi9 aluminum alloy. Castings were made by lost foam casting process with sand fluidization in mold at the stages of their solidification and cooling. Sand fluidization was achieved by blowing sand bed with compressed air in a foundry container. The metallographic study was carrying out on samples cut from different sections of the castings. Mechanical properties were determined on specimens made from cast samples. Microstructural analysis showed that sand fluidization increases the cooling rate, as a result, the main microstructural components of the alloy – SDAS, eutectic silicon and needles of the rich-iron phase – decrease. Moreover, in different sections of the casting structure is more uniform. With an increasing the air flow rate, a greater refinement of the structure is observed. Through the use of sand fluidization, the mechanical properties of LFC aluminum alloys increase to the level of gravity die castings.

11

Attempts to Prepare Precision Composite Castings by Sintering Al2O3/AlSi11 Using Underpressure

Szymański P., Gawdzińska K., Nagolska D.

Archives of Foundry Engineering

|

2020

|

Vol. 20, iss. 1

49--54

EN

This article presents the preparation of composite casts made using the technology of precise casting by the method of melted models. The composite was reinforced with the ceramic sinter from Al2O3 particle shaped in a printed polystyrene female mould, which was fired together with precured ceramics. The resulting ceramic preform, after being saturated with paraffin and after the filling system is installed, was filled with liquid moulding sand and fired together with the mould. The reinforcement was saturated by means of the counter-pressure exerting action on the metal column, being a resultant of pressures inside and outside the chamber. The preliminary assessment showed no apparent defects in the shape of the cast. The casting was measured and the figures were compared with the dimensions of the matrix in which the reinforcing preform was made, the preform after firing and after saturation with paraffin. The results were presented in a table and dimensional deviations were determined. The composite casting was subjected to metallographic tests, which excluded any porous defects or damage to the reinforcement. It can therefore be said that, according to the predictions resulting from the previous calculations, the pressure values used allowed for complete filling of the reinforcement capillaries. The proposed method is therefore suitable for the preparation of precision composite castings with complex shapes.

12

Application of Modular Die for Fluidity Test and Monitoring of the Pressing Force Flow by Semi-solid Squeeze Casting of AlSi7Mg0.3

Martinec D., Pastirčák R.

Archives of Foundry Engineering

|

2020

|

Vol. 20, iss. 3

69--73

EN

The fluidity is the term to determine the materials ability to fill the mold cavity properly. Fluidity is complex property with many variables. Up to this date, there is no methodology for defining the fluidity in a semisolid material state. Submitted paper deals with the proposal of a new method designed for aluminium alloy fluidity evaluation in semi-solid state trough the design of the layered construction die. Die will be primary used for fluidity tests of semi-solid squeeze casted aluminium alloy and to observe the pressing force flow by mentioned casting technology. The modularity consists of possibility to change each die segment. In the experiment the die design was evaluated by simulation in ProCAST 11.5 and by production of experimental castings. The die was made by laser cutting technology from construction steel S355JR. Experimental material was aluminium alloy AlSi7Mg0.3. The temperature of the semisolid state was chosen to achieve 35% of solid phase. The result of next study should be a selected parameters observation and their effect on the fluidity of aluminium alloy in semi-solid state. This will be very important step to determine the optimal conditions to achieve a castings with certain wall thickness produced by the method of semi-solid squeeze casting.

13

The Influence of Microwave Drying Parameters on the Properties of Synthetic Moulding Sands

Nowak D., Gal B., Włodarska A., Granat K.

Archives of Foundry Engineering

|

2019

|

iss. 4

51--54

EN

In this work, the influence of microwave drying parameters such as irradiation time and microwave power level on the properties of synthetic moulding sands is presented. Determination of compressive strength Rcs, shear strength Rts and permeability Ps of synthetic moulding sands with the addition of two different bentonites, after drying process with variable microwave parameters were made. The research works were carried out using the microwave oven with regulated power range of the electromagnetic field. From the results obtained, the significant influence of both drying time and microwave power level on the selected properties of moulding sands was observed. In comparison to the conventional drying method, microwave drying allows to obtain higher compressive strength of the synthetic moulding sand. The influence of application microwave irradiation on permeability was not observed. Higher strength characteristics and shorter drying time are major advantages of application of the electromagnetic irradiation for drying of the synthetic moulding sand with regard to conventional drying method.

14

Organic Moulding Sands for Production of Large-Size Castings

Major-Gabryś K., Hosadyna-Kondracka M.

Archives of Foundry Engineering

|

2019

|

iss. 3

99--105

EN

Recently, some major changes have occurred in the structure of the European foundry industry, such as a rapid development in the production of castings from compacted graphite iron and light alloys at the expense of limiting the production of steel castings. This created a significant gap in the production of heavy steel castings (exceeding the weight of 30 Mg) for the metallurgical, cement and energy industries. The problem is proper moulding technology for such heavy castings, whose solidification and cooling time may take even several days, exposing the moulding material to a long-term thermal and mechanical load. Owing to their technological properties, sands with organic binders (synthetic resins) are the compositions used most often in industrial practice. Their main advantages include high strength, good collapsibility and knocking out properties, as well as easy mechanical reclamation. The main disadvantage of these sands is their harmful effect on the environment, manifesting itself at various stages of the casting process, especially during mould pouring. This is why new solutions are sought for sands based on organic binders to ensure their high technological properties but at the same time less harmfulness for the environment. This paper discusses the possibility of reducing the harmful effect of sands with furfuryl binders owing to the use of resins with reduced content of free furfuryl alcohol and hardeners with reduced sulphur content. The use of alkyd binder as an alternative to furfuryl binder has also been proposed and possible application of phenol-formaldehyde resins was considered.

15

New Use of Instruments for More Accurate Wax Pattern Blade Segment Production

Herman A., Kubelková I., Vrátný O.

Archives of Foundry Engineering

|

2019

|

iss. 2

101--106

EN

Precision casting is currently motivated by high demand especially for castings for the aerospace, automotive and gas turbine industries. High demands on precision of this parts pressure foundries to search for the new tools which can help them to improve the production. One of these tools is the numerical simulation of injection process, whereas such software especially for investment casting wax injection, process does not exist yet and for this case must be the existing software, for alloys or plastic, modified. This paper focuses on the use of numerical simulations to predict the behavior of injected models of gas turbine blades segments. The properties of wax mixtures, which were imported into the Cadmould simulation software as a material model, were found. The results of the simulations were verified using the results of 3D scanning measurements of wax models. As a supporting technology for verifying the results was used the Infrared Thermography.

16

Lead-Free Casting Brasses. Investigations of the Corrosion Resistance and Shaping of Microstructure and Properties

Kozana J., Garbacz-Klempka A., Piękoś M.

Archives of Foundry Engineering

|

2019

|

iss. 2

113--118

EN

The ecological factor is very important in shaping properties of alloys. It leads to a limitation or elimination, from the surroundings, of harmful elements from the heavy metals group. The so-called eco-brasses group comprises common lead-free brasses containing 10 to 40% of zinc and arsenic brasses of a high dezincification resistance. Among standardized alloys, CW511L alloy ( acc. to EN standard) or MS-60 alloy (acc. to DIN) can be mentioned. Investigations were performed on two different kinds of metal charges: ingots cast by gravity and the ones obtained in the semi-continuous casting technology with using crystallizers. The casting quality was analysed on the basis of the microstructure images and mechanical properties. The investigations also concerned increasing the corrosion resistance of lead-free alloys. This resistance was determined by the dezincification tendency of alloys after the introduction of alloying additions, i.e. aluminium, arsenic and tin. The investigations focused on the fact that not only alloying additions but also the production methods of charge materials are essential for the quality of produced castings. The introduced additions of aluminium and tin in amounts: 0÷1.2 wt% decreased the dezincification tendency, while arsenic, already in the amount of 0.033 wt%, significantly stopped corrosion, limiting the dezincification process of lead-free CuZn37 brass. At higher arsenic contents, corrosion occurs only within the thin surface layer of the casting (20 μ).

17

Influence of Silica Sand on Surface Casting Quality

Beňo J., Adamusová K., Merta V., Bajer T.

Archives of Foundry Engineering

|

2019

|

iss. 2

5--8

EN

The current casting production of castings brings increased demands for surface and internal quality of the castings. Important factors, that influence the quality of casted components, are the materials used for the manufacture of moulds and cores. For the preparation and production of moulds and cores, in order to achieve a low level of casting defects, then it used a high quality input materials, including various types of sands, modified binders, additives, etc. However, even the most expensive raw materials are not a guarantee to achieve the quality of production. It is always necessary to choose the appropriate combination of input material together with an appropriate proposal for the way of the production, the metallurgical treatment of cast alloy, etc. The aim of this paper is to establish the basic principles for the selection of the base core mixtures components – sands to eliminate defects from the tension, specifically veining. Various silica sand, which are commonly used in foundries of Middle Europe region, were selected and tested.

18

Ceramic-Carbon Filters for Molten Metal Alloys Filtration

Asłanowicz M., Ościłowski A., Lipowska B., Witek J., Robak Z., Muzyka R., Kowalski P., Wańczyk K.

Archives of Foundry Engineering

|

2019

|

iss. 1

98--102

EN

In 2014 we finished research works involved in the development of a technology for manufacturing innovative ceramic-carbon foam filters for molten metal alloys filtration, which were financed by the National Centre for Research and Development (NCBiR) from INNOTECH programme resources. A batch of the filters produced in this technology was tested in practice in domestic cast steel and cast iron foundries. The trials were successful and foundries declared their intention to purchase the newly-developed filters for the current production of casts. This provided an incentive for “Ferro-Term” Sp. z o.o. to start design works on the prototype line for a serial production of these filters. At the same time, in co-operation with a scientific consortium, including the co-authors of the technology, i.e. the Institute of Ceramics and Building Materials, Refractory Materials Division in Gliwice, Institute for the Chemical Processing of Coal in Zabrze and Foundry Research Institute in Cracow, the company made a successful attempt to raise some funds for the necessary adaptation of the developed technology from the semi-technical to industrial scale from Intelligent Development Operational Programme. In the article we have presented information on the effects of works performed within the framework of the project entitled “Modernization and adaptation of the existing technological line for purposes related to technology verification and start-up of the production of innovative ceramic-carbon filters for molten metal alloy filtration”.

19

Cast Grates Used in Heat Treatment Furnaces

Piekarski B., Drotlew A.

Archives of Foundry Engineering

|

2019

|

iss. 3

49--54

EN

Examples of cast grates whose construction was based on previously used "old" patterns of the technological equipment for heat treatment furnaces (TEq) are presented. Manufacturers of this type of castings have at their disposal numerous earlier designs of the applied TEq. Their adaptation for the needs of a new order, i.e. the creation of a new design or modification of the already existing one, significantly reduces both cost and time of the implementation. It also allows making new grate constructions of various shapes and sizes, reducing in this way the number of patterns stored by the manufacturer of castings. The examples of cast grates shown and discussed in this study document the variety of ways that can be used when making them from the already existing patterns or castings. The presented grates were made using master patterns, entire castings or their fragments, and modular segments.

20

Thermally Hardened Moulding and Core Sands with Hydrated Sodium Silicate Designed for Al Alloy Castings

Major-Gabryś K. A., Grabarczyk A. P., Dobosz S. M.

Archives of Foundry Engineering

|

2018

|

Vol. 18, iss. 3

132--137

EN

The necessity of obtaining high quality castings forces both researchers and producers to undertake research in the field of moulding sands. The key is to obtain moulding and core sands which will ensure relevant technological parameters along with high environmental standards. The most important group in this research constitutes of moulding sands with hydrated sodium silicate. The aim of the article is to propose optimized parameters of hardening process of moulding sands with hydrated sodium silicate prepared in warm-box technology. This work focuses on mechanical and thermal deformation of moulding sands with hydrated sodium silicate and inorganic additives prepared in warm-box technology. Tested moulding sands were hardened in the temperature of 140ºC for different time periods. Bending strength, thermal deformation and thermal degradation was tested. Chosen parameters were tested immediately after hardening and after 1h of cooling. Conducted research proved that it is possible to eliminate inorganic additives from moulding sands compositions. Moulding sands without additives have good enough strength properties and their economic and ecological character is improved.