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Year 1999 No 1

MIŠIČKO R., LONGAUEROVÁ M., HORÁK M., LEŠKO A.
STRAIN-INDUCED PRECIPITATION IN AUSTENITE OF NB-V MICROALLOYED STEEL
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No 1 (1999), p. 6-11
  mag01.pdf (96 kB)
mag01_eng.txt (2 kB)  

Ivan J., Besterci M., Zbíral J., Edtmaier Ch., Šlesár M.
STATISTICAL DISTRIBUTION OF Y2O3 PARTICLE SIZE IN THE SYSTEM PT-Y2O3 BY MEANS OF THE STEM METHOD
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No 1 (1999), p. 12-15
  mag02.pdf (84 kB)
mag02_eng.txt (879 B)  

Lux L., Heželová M., Gálová M., Markušová K.
PARAFFIN IMPREGNATED GRAPHITE ELECTRODEFOR THE INVESTIGATION OF THE SURFACE STATE OF POWDER MATERIALS
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No 1 (1999), p. 16-23
  mag03.pdf (121 kB)
mag03_eng.txt (2 kB)  

Zrník J., Besterci M., Kováč L.
CREEP-FATIGUE BEHAVIOUR OF REINFORCED MECHANICALLY ALLOYED SYSTEM AL - AL4C3
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No 1 (1999), p. 24-31
  mag04.pdf (199 kB)
mag04_eng.txt (2 kB)  

Pernis R.
DRAWING OF THICK WALL TUBES USING FLOATING PLUG
Abstract
Production of thick wall tubes using floating plug belongs to marginal techniques, which are different from drawing of regular tubes. The report analyses possibilities of thick wall tubes by the technology of drawing with floating plug.
For this technology the criterion is specified, by means of which the geometric similarity is evaluated. Suitable index, to express the tubes geometric similarity, the wall-thickness value was chosen, showing the tube diameter to wall thickness D/t ratio. Drawing tubes with floating plug, the thick-walled tubes are considered, when the wall-thickness value is lower than 5. The basic tools used in the tubes drawing with floating plug technique are a drawing die and a plug. As seen from the pictures the relationship is to some extend characterized by the clearence v and the interference p, which are marked as the tools parameters. Clearence v represents the difference between the tube inside diameter and plug head. Interference p is the difference between plug head diameter and tube after drawing external diameter. On the basis of interference analysis, the term corrected interference P was accepted, which is the sum of clearence v and interference p.
For common tubes drawing with floating plug with negative interference the interference coefficient kP, was defined which shows the interference intensity and is defined as the ratio of corrected interference P to the tube exit thickness. The greater the interference intensity the smaller kP coefficient. The interference coefficient kP is shown to influence the applicability of tube drawing with flowing plug technology.
Common algorithm is shown, which describes individual steps, for the final tube dimensions to determine pre-drawing tube parameters or the initial tube dimensions. On the basis of the presented algorithm, the calculation for Cu thick-walled tube ? 3x0,7 mm is made. Comparision with verified production process for Cu tube ? 3,03x0,72 mm is also shown.
It sets up the conditions under which the drawing of thick wall tubes can be realised and how to determine dimensions of certain tools to assure stabilised drawing procedure. The result of theoretical studies and practical verification is that possibility of thick wall tubes drawing with floating plug with negative difference of die and plug diameters is approved. This allows further extension of technological limits of tubes drawing with floating plug. Production of small diameter thick wall tubes with calibrated internal surface is a practical contribution.
It was confirmed for Cu small diameters thick-wall tubes drawn with floating plug, that much higher extension coefficient from the tube diameter ?D is admissible, than is for regular tubes. There is an assumption, the drawing conditions with floating plug verified on Cu thick wall tubes will be applicable on other materials, for example: brass, aluminium alloys, nickel, steel and others. The basic assumption is the equality of tubes geometric similarity coefficients.

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No 1 (1999), p. 32-43
  mag05.pdf (215 kB)
mag05_eng.txt (3 kB)  

Cehlár M., Kyseľová K.
ASSESSMENT OF ECONOMIC EFFICIENCY OF JV KOSICE COMPANY (CARNAUDMETALBOX - VSZ KOSICE)
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No 1 (1999), p. 44-52
  mag06.pdf (201 kB)
mag06_eng.txt (7 kB)  

Longauerová M., Grutková J., Grígerová T., Beháň B.
METALLOGRAPHY OF AG-CU ALLOYS
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No 1 (1999), p. 53-60
  mag07.pdf (154 kB)
mag07_eng.txt (2 kB)  

Valenčík Š., Cengel P.
THE MANUFACTURING SYSTEM OF RECYCLING OF ALUMINIUM WASTE
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No 1 (1999), p. 61-69
  mag08.pdf (206 kB)
mag08_eng.txt (2 kB)