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1

Analysis of the State of Stress in the Connection of Graphite Electrodes

Piekło J., Maj M.

Archives of Foundry Engineering

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2015

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Vol. 15, iss. 1 spec.

85--88

EN

The paper examines various issues related to the state of stress occurring in the connection of graphite electrodes during their lifetime when operating in electric arc furnaces. It also discusses the impact of graphitization process on the electrode strength. Based on the results of numerical calculations supported by experimental studies, the effect on the connection durability of its design and technological process parameters was determined.

2

Solidification of superalloys in shell moulds and its numerical simulation

Roučka J., Kováč M., Odložil J., Hrbáček K.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 1

137-146

EN

The paper presents the results of the experiments on the solidification of superalloys in shell moulds. The analysis of heat transfer during the solidification of castings in ceramic moulds was carried out theoretically and confirmed by the results of earlier experiments conducted on model shells. Results of experimental temperature measurement were compared with numerical calculations (performed using the ProCast software) and corrections of the calculation parameters were proposed. A model of structure simulation was verified on a selected real casting. It can be assumed that simulating the structure will be a theoretically and computationally demanding problem.

3

Research on possibility of microwave measurements application for determination of adhesive ingredient content in moulding sand

Nowak D., Granat K., Stachowicz M., Jaworski G.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 3

129--132

EN

This paper presents preliminary results of the research on possibility of determination of adhesive material content in classical moulding sands with application of microwave measurements. Presented results have been obtained by measurements with microwave slotted line. Information about bonding clay content has been derived from measurements of reflection coefficient and VSWR of tested substrate sample. The presented measurement method allows for fast and accurate measurements.

4

Bainite obtaining in cast iron with carbides castings

Pietrowski S., Gumienny G.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 1

109-114

EN

In these paper the possibility of upper and lower bainite obtaining in cast iron with carbides castings are presented. Conditions, when in cast iron with carbides castings during continuous free air cooling austenite transformation to upper bainite or its mixture with lower bainte proceeds, have been given. A mechanism of this transformation has been given, Si, Ni, Mn and Mo distribution in the eutectic cell has been tested and hardness of tested castings has been determined.

5

Water mist effect on cooling range and efficiency of casting die

Władysiak R.

Archives of Foundry Engineering

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2008

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Vol. 8, iss. 4

213-218

EN

This project is showing investigation results of cooling process of casting die in the temperature range 570÷100 °C with 0.40 MPa compressed air and water mist streamed under pressure 0.25÷0.45 MPa in air jet 0.25÷0.50 MPa using open cooling system. The character and the speed of changes of temperature, forming of the temperture’s gradient along parallel layer to cooled surface of die is shawing with thermal and derivative curves. The effect of kind of cooling factor on the temperature and time and distance from cooling nozzle is presented in the paper. A designed device for generating the water mist cooling the die and the view of sprying water stream is shown here. It’s proved that using of the water mist together with the change of heat transfer interface increases intensity of cooling in the zone and makes less the range cooling zone and reduces the porosity of cast microstructure.

6

The structure of the alphinizing coat on alloy steels

Pietrowski S., Szymczak T.

Archives of Foundry Engineering

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2008

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Vol. 8, iss. 4

229-235

EN

In this paper results of the structure of the coat alphinizing in AlSi5 silumin on alloy steels: acid-proof 1H18N9T (X6CrNiTi18-10) and high speed SW18 (HS18-0-1) were presented. The temperature of the alphinizing bath was amounts to750š5°C, and immersion time of the element [tau] = 180s. It was shown, that there is the different "g" coat thickness on testing steels. On the 1H18N9T steel it amounts to g = 52[mikro]m, and on the SW18 steel - g = 203[mikro]m. Regardless of a grade of testing alloy steels the coat consist of three layers with diversified phasic structure. There is different chemical composition of coat layers on testing steels. The first layer from the base consist of AlFe phase containing alloy addictions of steels: Cr and Ni (1H18N9T) and W, V and Cr (SW18). On this layer crystallize the second layer of intermetallic phases. It is the phase containing the main alloy addiction of steels: AlFeCr (1H18N9T) and AlFeW (SW18). The last, outside layer consist of silumin containing AlFeNi intermetallic phases on the 1H18N9T steel and AlFeW on the SW18 steel. Regardless of the grade of testing steels there is Si element in all layers of the coat. There are morphological differences in tested layers. The second layer (AlFeW phase) inside the coat on the SW18 steel consist of faced crystals growing into in outside silumin layer. On the 1H18N9T steel a boundary between transient and outside layer is more uniform. Free separations of intermetallic phases inside silumin layer on the 1H18N9T steel have lamellar and on the SW18 steel - faced form.

7

The influence of microwave curing time and water glass kind on the properties of molding sands

Granat K., Nowak D., Pigiel M., Stachowicz M., Wikiera R.

Archives of Foundry Engineering

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2007

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Vol. 7, iss. 4

79-82

EN

This work presents results of research on the influence of microwave heating time on the process of hardening of water glass molding sands. Essential influence of this drying process on basic properties such as: compression, bending and tensile strength as well as permeability and wear resistance, has been found. It has been proved, that all the investigated sorts of sodium water glass could be used as binding material of molding sands intended for curing with the microwave process heating. It has been found, while analyzing the results of property studies of microwave heated molding sands with 2.5% addition of water glass, that all available on the market kinds of this binding agent (including the most frequently used in foundry 145 and 149 kinds) after microwave heating guarantee very good compression, bending and tensile strength as well as permeability and wear resistance. Moreover, it has been determined that the optimal curing time of molding sands containing various kinds of water glass is 240 seconds. After this time, all basic properties of molding sands are stable. The use of microwave curing of water glass molding sands results in a significant decrease of hardening process time, full stabilization of molding sands as well as much lower energy consumption.

8

Reengineering of permanent mould casting with lean manufacturing methods

Władysiak R.

Archives of Foundry Engineering

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2007

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Vol. 7, iss. 3

205-212

EN

At the work were introduced main areas of production system project of casts produced in permanent moulds, that constitutes reengineering of conventional production system according to Lean Manufacturing (LM) methods. New resolution of cooling of dies with water mist was shown to casting of car wheels made from aluminium alloys in low pressure casting process. It was implemented as a part of goal-oriented project in R.H. Alurad Sp.z o.o. in Gorzyce. Its using intensifies solidification and self-cooling of casts shortening the time of casting cycle by the 30%. It was described reorganizing casting stations into multi-machines cells production and the process of their fast tool's exchange with applying the SMED method. A project of the system was described controlling the production of the foundry with the computer aided light Kanban system. A visualization of the process was shown the production of casts with use the value stream mapping method. They proved that applying casting new method in the technology and LM methods allowed to eliminate down-times, to reduce the level of stocks, to increase the productivity and the flow of the castings production.

9

Microwaves energy in curing process of water glass molding sands

Granat K., Nowak D., Pigiel M., Stachowicz M., Wikiera R.

Archives of Foundry Engineering

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2007

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Vol. 7, iss. 1

183-188

EN

This work presents the results of investigation of microwave heating on hardening process of water glass molding sands. Essential influence of this heating process on basic properties such as: compression, bending and tensile strength as well as permeability and abrasion resistance has been found. It has been proved, that all investigated sorts of sodium water glass with a module between 2.0 and 3.3 can be used as a binder of molding sands in microwave curing process. It has been found during analysis of research results of sands with 2.5 % water glass addition that they are practically the same as in case of identical molding sands dried for 120 minutes at the temperature of 110°C, used for comparative purposes. Application of microwave curing of molding sands with water glass, however, guarantees reduction of hardening time (from 120 to 4 minutes) as well as significant reduction of energy consumption. Attempts of two stage hardening of the investigated water glass molding sands have also been carried out, that is after an initial hardening during a classical CO_2 process (identical sands have also been tested for comparison after CO_2 blowing process) and additional microwave heating. It has been found that application of this kind of treatment for curing sands with 2.5 % sodium water glass content and module from 2.0 up to 3.3 results in the improvement of properties in comparison to classical CO_2 process.

10

Influence of conditions of preparing the foamed plaster on its degree of foaming

Pawlak M.

Archives of Foundry Engineering

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2007

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Vol. 7, iss. 3

105-110

EN

Foamed plaster moulds are used in precision casting process of non-ferrous alloys. Casting from those moulds are characterizedby high dimensional accuracy, very good shape pattering and small surface roughness. However, a drawback of the plaster mould is very low permeability. A substational improvement of this parametr may be achived through physical or phisico-chemical treatment of the plaster slurry or prepared mould. The most advantageous results can be obtained by foaming the slurry. The investigatious comprised evaluation of the influence of mixing parametrs (mixer type, rotation and mixing time, settings the mixer in mixing device) and the content of a foaming agent on the degree of foaming of the plaster. The tests were carried out using the [alpha]-plaster Hartform-H1 and Alkanol XC as a foaming agent. The structure of a slurry produced after foaming is non-homogeous. Therefore, the investigations were completed by making appropriate of this process. Analysis of the results leads to the conclusion, that the foamed plaster Hartform-H1 reaches the top degree of foaming at the following parameters: the water/plaster ratio W/G=0.55, the content of Alkanol XC a=0.07%, stirring with a perforate disc mixer at the rotation speed nm=4000 rpm during ôm=30 s. In turn the top homogeneity of the foamed plaster slurry can be achieved at the rotation speed nu=1400 rpm during ôu=30 s., while other parameters are the same as in the foaming process. The obtained results can provide the basis for the elaboration of the industry procedures useful in the production of the plaster moulds for precision casting.

11

Influence Cr on crystallization and the phase transformations of the bronze BA1044

Pisarek B. P.

Archives of Foundry Engineering

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2007

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Vol. 7, iss. 3

129-136

EN

The investigations were introduced in the paper, method of thermal and derivative analysis (TDA), the process of crystallization and phase transformation in the solid state of the aluminium bronze CuA110Fe4Ni4 (BA1044) and with the addition 0.3 % Cr. Two intermetallic phase were identified in the microstructure of the bronze BA1044: [kappa]Fe1-- rich in Fe and Cu and [kappa]Fe2 - rich in Fe, and in the microstructure of the bronze BA1044+0.3 % Cr only one phase [kappa]Fel - rich in Fe, Cu and Cr. The presence of chrome in the bronze BA1044 reduce size the primary crystals of the phase [beta], reduces the dynamics of the processes of thermal phase transformation in the solid state and lengthens the time their of duration.

12

Hybrid foundry patterns of bevel gears

Budzik G., Markowski T., Sobolak M.

Archives of Foundry Engineering

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2007

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Vol. 7, iss. 1

131-134

EN

Possibilities of making hybrid foundry patterns of bevel gears for investment casting process are presented. Rapid prototyping of gears with complex tooth forms is possible with the use of modern methods. One of such methods is the stereo-lithography, where a pattern is obtained as a result of resin curing with laser beam. Patterns of that type are applicable in precision casting. Removing of stereo-lithographic pattern from foundry mould requires use of high temperatures. Resin burning would generate significant amounts of harmful gases. In case of a solid stereo-lithographic pattern, the pressure created during gas burning may cause the mould to crack. A gas volume reduction may be achieved by using patterns of honeycomb structure. However, this technique causes a significant worsening of accuracy of stereo-lithographic patterns in respect of their dimensions and shape. In cooperation with WSK PZL Rzeszów, the Machine Design Department of Rzeszow University of Technology carried out research on the design of hybrid stereo-lithographic patterns. Hybrid pattern consists of a section made by stereo-lithographic process and a section made of casting wax. The latter material is used for stereo-lithographic pattern filling and for mould gating system. The hybrid pattern process consists of two stages: wax melting and then the burn-out of stereolithographic pattern. Use of hybrid patterns reduces the costs of production of stereolithographic patterns. High dimensional accuracy remains preserved in this process.