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Year 2005 No 3

Dobrovský Ľ., Řeháčková L., Dobrovská J., Stránský K., Dobrovská V.
PREDICTION OF CARBON DISTRIBUTION IN WELDED JOINTS OF STEELS
Keywords: Quasi-stationary diffusion|welded joints of steels|interstitial elements|carbon|
No 3 (2005), p. 259-265
  mag01.pdf (172 kB)
mag01_eng.txt (2 kB)  

Noga Z.
LABORATORY PLASMA EQUIPMENT TO THE SEMI-CONTINUAL MATERIAL MELTING AND PROCESS
Keywords: Development of research equipment|plasma torch|horizontal-vertical water cooled copper crucible|electric heating–treatment furnace|forming machines|
No 3 (2005), p. 266-276
  mag02.pdf (948 kB)
mag02_eng.txt (3 kB)  

Kocich R., Greger M.
DEVELOPMENT OF STRUCTURE AND MECHANICAL PROPERTIES IN AZ91 ALLOY USING BY ARB PROCESS
Keywords: Plastic deformation|grain size|magnesium alloy|mechanical properties|
No 3 (2005), p. 277-283
  mag03.pdf (735 kB)
mag03_eng.txt (1 kB)  

Szurman I., Kursa M.
INFLUENCE OF CONDITIONS OF PREPARATION ON STRUCTURAL CHARACTERISTICS OF NI-TI ALLOYS
Keywords: Ni-Ti shape memory alloys|plasma melting|vacuum induction melting|
No 3 (2005), p. 284-292
  mag04.pdf (539 kB)
mag04_eng.txt (2 kB)  

Smíšek V., Kursa M.
POSSIBILITIES OF AFFECTING THE LAMELLAR MICROSTRUCTURE OF TI 46AL-5NB-1W ALLOY BY DIRECTIONAL CRYSTALLISATION
Keywords: titanium aluminide|directional solidification|directional crystallisation|microstructure|
No 3 (2005), p. 293-300
  mag05.pdf (413 kB)
mag05_eng.txt (1 kB)  

Bujnošková K., Drápala J.
SEGREGATION PHENOMENA IN REFRACTORY METALS DURING ZONE MELTING
Keywords: Segregation|refractory metals|molybdenum|tungsten|segregation coefficient|concentration undercooling|convection|
No 3 (2005), p. 301-310
  mag06.pdf (308 kB)
mag06_eng.txt (2 kB)  

Bystrianský J., Siegl J., Haušid P., Strnadel B.
THERMAL FATIGUE OF STAINLESS STEELS
Keywords: Stainless steel|thermal shock|thermal fatigue|fatigue crack|thermal cycle|
No 3 (2005), p. 311-322
  mag07.pdf (2 MB)
mag07_eng.txt (2 kB)  

Bystrianský J., Siegl J., Haušid P., Strnadel B.
THERMAL FATIGUE OF STAINLESS STEELS
Keywords: Stainless steel|thermal shock|thermal fatigue|fatigue crack|thermal cycle|
No 3 (2005), p. 311-322
  mag08.pdf (2 MB)
mag08_eng.txt (2 kB)  

Sojka J., Jonšta P., Rytířová L., Sozańska M., Jerôme M.
INFLUENCE OF MICROSTRUCTURE ON SULPHIDE STRESS CRACKING OF HOT ROLLED TUBES
Keywords: Sulphide stress cracking|carbon steel|segregation bands|hydrogen permeation|
No 3 (2005), p. 332-330
  mag09.pdf (865 kB)
mag09_eng.txt (2 kB)  

Schindler I., Fiala J., Černý L., Kohut J., Kozelský P., Suchánek P.
DEFORMATION BEHAVIOR AND MICROSTRUCTURE DEVELOPMENT OF 13CR25 FERRITIC STAINLESS STEEL IN HOT STRIP ROLLING
Keywords: High-alloy ferritic steel|hot strip rolling|simulation|recrystallization|recovery|grain size|mean equivalent stress|
No 3 (2005), p. 331-340
  mag10.pdf (1 MB)
mag10_eng.txt (2 kB)  

Fabík R., Kliber J.
INVERSE ANALYSIS CALCULATION OF HEAT TRANSFER COEFFICIENT FOR FEM SIMULATION OF RAILS HARDENING
Abstract
The present paper concerns determination of boundary conditions for mathematical modelling of heat transfer. In particular, it covers determination of heat transfer coefficient ? during ambient air cooling of steel rails on cooling bed and during accelerated cooling of a part of rail web by submerging in still water. First sub-section covers measurement of cooling curves for both heat treatment processes. Eleven thermocouples placed in drilled holes have been used for the measurements. The following chapter contains calculation of the heat transfer coefficient based on heat flux obtained by analysis of the time dependence of gradient between two thermocouples placed closed to the rail surface. The mathematical-physical background of the calculation is given in a special sub-section of the study. The obtained results were compared with inverse analysis results. The inverse analysis involved inverse calculation by finite element method (with the aid of FormFEM software for forming process simulation) and processing of measured cooling curves to obtain a new relationship between heat transfer coefficient ? and temperature of the rail surface during cooling. The paper discusses the causes of the discrepancies between results (particularly during accelerated cooling in water) of both methods and between the theoretical values. There is a summary of the impact of formation of rail head steam cushion upon the amount of extracted heat. Inversion analysis results corrected with respect to generated phase transformation heat were used for mathematical modelling of the laboratory experiment in the initial setting. Resulting cooling curves were in excellent agreement with measured values.

Keywords: cooling curves|inverse analysis|FEM|heat transfer coefficient|
No 3 (2005), p. 341-350
  mag11.pdf (1 MB)
mag11_eng.txt (2 kB)  

Heger M. , Schindler I., Franz J., Špička I., Turoňová P., Černý L.
POSSIBILITIES OF COMPUTER ANALYSIS EXPLOITATION IN THE PROCESS OF SOLUTION SOME TASKS CONNECTED WITH MATERIAL FORMING
Keywords: Rolling|equivalent strain|strain rate|computer analysis|
No 3 (2005), p. 351-361
  mag12.pdf (1 MB)
mag12_eng.txt (2 kB)  

Kubina T., Schindler I., Heger M., Plura J., Bořuta J., Dänemark J., Hadasik E.
STATISTICAL COMPARISON OF DIFFERENT METHODS OF CALCULATION OF PARAMETERS DESCRIBING DYNAMIC RECRYSTALLIZATION
Keywords: Activation energy|hot forming|steel|dynamic recrystallization|
No 3 (2005), p. 362-368
  mag13.pdf (332 kB)
mag13_eng.txt (1 kB)  

Lasek S., Drápala J., Urbaníková Ž., Blahetová M.
COMPARISON OF ELECTROCHEMICAL CORROSION PROPERTIES OF SELECTED LEAD-FREE SOLDERS
Keywords: Tin alloys|lead-free solders|electrochemical corrosion|potentiodynamic polarization method|
No 3 (2005), p. 369-374
  mag14.pdf (220 kB)
mag14_eng.txt (2 kB)