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D. Nowak

Abstract

The paper presents results of preliminary examinations on possibility of determining binder content in traditional moulding sands with the microwave method. The presented measurements were carried-out using a special stand, the so-called slot line. Binder content in the sandmix was determined by measurements of absorption damping Ad and insertion losses IL of electromagnetic wave. One of main advantages of the suggested new method of binder content measurement is short measuring time.

Open access

D. Nowak

Abstract

This paper presents the impact of microwave penetration depth on the process of heating the moulding sand with sodium silicate. For each material it is affected by: the wavelength in vacuum and the real and imaginary components of the relative complex electrical permittivity εr for a selected measurement frequency. Since the components are not constant values and they change depending on the electrical parameters of materials and the frequency of the electromagnetic wave, it is indispensable to carry out laboratory measurements to determine them. Moreover, the electrical parameters of materials are also affected by: temperature, packing degree, humidity and conductivity. The measurements of the dielectric properties of moulding sand with sodium silicate was carried out using the perturbation method on a stand of waveguide resonance cavity. The real and imaginary components of the relative complex electrical permittivity was determined for moulding sand at various contents of sodium silicate and at various packing degrees of the samples. On the basis of the results the microwave penetration depth of moulding sand with sodium silicate was established. Relative literature contains no such data that would be essential to predicting an effective process of microwave heating of moulding sand with sodium silicate. Both the packing degree and the amount of sodium silicate in moulding sand turned out to affect the penetration depth, which directly translates into microwave power density distribution in the process of microwave heating of moulding sand with sodium silicate.

Open access

D. Nowak, K. Granat and B. Opyd

Abstract

Within the research, carried-out were examinations of foundry rejects in form of waste moulding and core sands in order to determine effectiveness of the microwave utilization process. Presented are measurements of permittivity and loss tangent that determine behaviour of materials in electromagnetic field. Measurements were performed on a stand of waveguide resonance cavity that permits precise determination of the above-mentioned parameters with the perturbation method. Examination results of five waste moulding sands confirm that effectiveness of microwave utilization depends on electrical properties of the sandmixes (permittivity and loss tangent).

Open access

D. Kopyciński, D. Siekaniec, A. Szczęsny, E. Guzik and A. Nowak

Abstract

The results of studies of the effect of different amounts of the Fe-Ti inoculant on structure and selected mechanical properties of High Chromium Cast Iron (conventionally abbreviated as HCCI) are presented. The main purpose of the inoculation is structure refinement and hence the improvement of casting properties. Generally considered a strong carbide-forming element, titanium is an effective inoculant for the high chromium cast iron. However, there is an optimal amount of titanium addition beyond which the mechanical properties begin to deteriorate. The studies enabled determining the amount of Fe-Ti inoculant optimal for the cast iron of a given chemical composition.

Open access

D. Nowak, B. Gal, K. Granat, G. Jaworski and R. Więcławek

Abstract

The presented research was aimed at searching for an exact and effective method of determining moisture content in traditional moulding sands. By measuring resonance frequency and quality factor of a waveguide resonance cavity, relative permittivity was determined for different synthetic moulding sands. Analysis of the presented results confirms a linear relation between relative permittivity values and moisture content values in the selected traditional moulding sands. The obtained linear relationship can be used as a reference characteristic for evaluation of humidity of moulding sand.

Open access

K. Granat, B. Opyd, D. Nowak, M. Stachowicz and G. Jaworski

Abstract

The paper describes preliminary examinations on establishing usefulness criteria of foundry tooling materials in the microwave heating technology. Presented are measurement results of permittivity and loss tangent that determine behaviour of the materials in electromagnetic field. The measurements were carried-out in a waveguide resonant cavity that permits precise determination the above-mentioned parameters by perturbation technique. Examined were five different materials designed for use in foundry tooling. Determined was the loss factor that permits evaluating usefulness of materials in microwave heating technology. It was demonstrated that the selected plastics meet the basic criterion that is transparency for electromagnetic radiation.

Open access

D. Kopyciński, E. Guzik, A. Nowak, M. Ronduda and M. Sokolnicki

Preparation Vermicular Graphite in Thin and Thick Wall Iron Castings

The results of studies on the use of magnesium alloy in modern Tundish for production of vermicular graphite cast irons were described. This paper describes the results of using a low-magnesium ferrosilicon alloy for the production of vermicular graphite cast irons. The paper presents a vermicular (and nodular) graphite in different walled castings. The results of trials have shown that the magnesium Tundish process can produce high quality vermicular graphite irons under the specific industrial conditions of Foundries - Odlewnie Polskie S.A. in Starachowice. In this work describes too preliminary studies on the oxygen state in cast iron and their effect on graphite crystallization.

Open access

U. Pasławska, D. Zyśko, A. Noszczyk-Nowak and R. Pasławski

Short-term and long-term PQ, QT and R-R intervals' variability at the resting condition and after exercise testing in healthy Anglo-Arabian horses

The duration of electrocardiographic (ECG) parameters: PQ, QT and R-R intervals change during long-term and short-term observation as the consequence of the fluctuations in autonomic nervous system activity among others dependent on the exercise and resting. There is no data of horse breed influence on these parameters.

The aim of the study was to assess the duration and the variability of the PQ, QT and R-R intervals in the resting conditions and after exercise testing in Anglo-Arabian horses.

Material and Methods: 27 healthy Anglo-Arabian horses aged 3.4 ± 1.0 years (15 male, 12 female) had ECG examination in the standing position using Einthoven system of leads. The longest and the shortest PQ, QT and R-R intervals were measured after night rest and after exercise testing and the means were calculated.

Conclusions: 1) In Anglo-Arabian horses the difference between the longest and the shortest PQ interval at rest vs. after exercise is 0.06 ± 0.05 vs. 0.03 ± 0.02, QT interval is 0.04 ± 0.03 vs. 0.04 ± 0.04, R-R interval 0.19 ± 0.15 vs. 0.08 ± 0.11. 2) The PQ and R-R intervals reveal high short-term variability either at the resting conditions or after exercise testing. 3) After exercise testing PQ, QT and R-R intervals are shorter than at the resting conditions. The delta PQ and R-R are 2 times smaller in contrast to delta QT which is constant. 4) The PQ and R-R interval variability was greater at the baseline condition than after exercise testing. The QT variability was similar at baseline condition to that after exercise testing.

Open access

M. Szymanek, B. Augustyn, D. Kapinos, S. Boczkal and J. Nowak

Abstract

The paper presents the technological aspect of the process of casting, crushing and plastic consolidation of semi-finished products from magnesium alloy. The aim of this study was to produce by the rapid solidification process a magnesium alloy from the MgAl9Zn1 family in the form of ribbons with ultrafine grain structure. The material cast in the melt spinning device was next crushed and subjected to the operation of cold consolidation and hot extrusion. The paper presents different stages of the process, including initial characterisation of the obtained material.

Open access

D. Kopyciński, D. Siekaniec, A. Szczęsny, M. Sokolnicki and A. Nowak

Abstract

The paper presents results of the possibility of adapting the Althoff-Radtke test for High Chromium Cast Iron. The Althoff-Radtke test is a clump attempt used for steel. The Althoff-Radtke test has four different lengths of clamp which qualifies it as a test to quantitatively take into account different kinds of shrinkage ΔL. The length of the slot of the cracked corner and the length of each staple (50 - 350 mm) are the parameters tendency to cast cracks. Castings of white cast iron have a high tendency to hot cracking due to the large range of solidification temperatures, unfavorable kinetics parameters of shrinkage, and especially a lack of expansion before shrinkage. Shrinkage of high chromium white cast iron is similar to the shrinkage of cast steel, and is approximately 2%. Therefore it is important to test susceptibility to hot cracks. Research was carried out under industrial conditions. Four melts were performed, one of the initial chemical composition and the other three modified by different amounts of Fe-Ti, respectively, 0.25%, 0.5% and 0.75% Fe-Ti. The propensity for hot cracking was based on the observation of the dark surface in the corner of the sample. The study shows that the Althoff-Radtke test can be adapted to determine the tendency for hot cracking of high chromium cast iron. It should however be noted that the test results cannot be compared with those for other alloys.