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Year 2007 No 1

Dobrovská J., Stránský K., Dobrovská V.
SEGREGATION BEHAVIOUR AND CHEMICAL HETEROGENEITY OF AS-CAST AND HEAT TREATED NICKEL-BASED SUPERALLOY IN 738LC
Keywords: Nickel alloys|Solidification|Segregation|Partition coefficient|Fourier number|
No 1 (2007), p. 7-16
  mag01.pdf (483 kB)
mag01_eng.txt (3 kB)  

Longauerová M., Fedorová M., Longauer S., Kadlec J., Bořuta J., Fujda M., Janák G., Vojtko M.
HETEROGENEITIES OF CHEMICAL COMPOSITON IN CAST PRODUCTS
Keywords: Slabs|surface segregation|structure heterogeneities|centreline noncompactibilities|round blooms|central segregation|
No 1 (2007), p. 17-25
  mag02.pdf (293 kB)
mag02_eng.txt (3 kB)  

Takahashi M., Ikeuchi K.
ELECTROSTATICALLY INDUCED PRECIPITATION OF SILVER IN SILVER-IMPREGNATED GLASS ANODICALLY-BONDED TO SILICON
Keywords: anodic bonding|silicon|glass|silver|ion substitution|prevention of joint defect|
No 1 (2007), p. 26-35
  mag03.pdf (2 MB)
mag03_eng.txt (1 kB)  

Bujnošková K., Drápala J.
STUDY OF SEGREGATION CHARACTERISTICS OF TANTALUM IN SINGLE CRYSTALS OF LOW-ALLOYED TUNGSTEN AND MOLYBDENUM ALLOYS
Keywords: segregation|tungsten|molybdenum|tantalum|zone melting|segregation coefficient|
No 1 (2007), p. 36-43
  mag04.pdf (208 kB)
mag04_eng.txt (2 kB)  

Greger M., Kocich R., Kuřetová B., Kander L.
MICROSTRUCTURAL EVOLUTION OF MAGNESIUM ALLOYS
Keywords: magnesium alloys|deformation|rolling|torsion test|
No 1 (2007), p. 44-51
  mag05.pdf (674 kB)
mag05_eng.txt (2 kB)  

Dománková M., Marek P., Moravčík R.
EFFECT OF ANNEALING AT 650°C ON PRECIPITATION IN CHOSEN AUSTENITIC STAINLESS STEELS
Keywords: austenitic stainless steels|sensitisation|precipitation|secondary phases|intergranular corrosion|
No 1 (2007), p. 52-60
  mag06.pdf (897 kB)
mag06_eng.txt (3 kB)  

Marek P., Dománková M.
INFLUENCE OF 40 % DEFORMATION ON SENSITISATION CHARAKTERISTIC OF 316 AND 316 L AUSTENITIC STAINLESS STEELS
Abstract
Sensitisation behavior of austenitic stainless steels are greatly influenced by several metallurgical factors such a chemical composition, degree of prior deformation, grain size, aging temperature-time. AISI type 316 stainless steel with two different chemical composition (varying mainly in carbon) were considered for the present study. The plates of analyzed steels were cut into strips of 150 x 100 mm and solution annealed (1100°C/1 h, water quenched) to eliminate any carbide precipitates formed during processing. The as-received material in mill-annealed condition was taken as reference corresponding to cold working of 0%. The as received sheets were cold rolled at ambient temperature to various levels of reduction in thickness ranging to 40%. In austenitic stainless steels 316 and 316 L were studied influence of prior deformation on degree of sensitization after isothermal sensitization in the temperature range from 500 to 900°C using different holding times from 0,02 to 100 h.
For determination the steels sensitivity to intergranular corrosion an oxalic acid etched test (ASTM A262 practice A) was used. The specimens were electrolytically etched in 10% oxalic acid for 90 sec. at a current density of 1 A/cm2. The etched structure is then examined at 250 x and was characterized as step, dual or ditch structure. The specimen showing step or dual structure was considered to be free from sensitization whereas the specimen showing ditch structure was classified as sensitized.
The sensitisation behaviour of AISI 316 and 316L austenitic stainless steels having different chemical composition was studied for various degrees of CW ranging 0% to 40% reduction in thickness. From the results obtained TTS diagrams were constructed.
These diagrams were obtained by plotting sensitisation tests results on a temperature versus log soaking time axes and drawing a line which demarcates the sensitized and non-sensitized regions.
The results showed, that effects of plastic deformation accelerated sensitization, and kinetics precipitation of secondary phases, especially chromium rich carbides (Fe,Cr)23C6. Precipitation of secondary phases in the deformated material was observed at the GB and intragranularly within the matrix too.
Minimum time required for sensitisation at nose temperature (tmin) was determined at 800°C for AISI 316 and at 750°C for AISI 316L. For AISI 316 and 40 % CW goes C-curve to lower times by the same temperature. For AISI 316L, the TTS diagrams are shifted towards lesser time and lower temperature than that of 0 % CW material.
Keywords: austenitic stainless steels|deformation|sensitisation|precipitation|
No 1 (2007), p. 61-67
  mag07.pdf (1 MB)
mag07_eng.txt (3 kB)  

Hajduga M., Jędrzejczyk D.
THE EFFECT OF OXIDE PRECIPITATION ON THE QUALITY OF STEEL ELEMENTS SHAPED BY GAS CUTTING
Keywords: high temperature oxidation|gas cutting|oxide precipitations|
No 1 (2007), p. 68-75
  mag08.pdf (633 kB)
mag08_eng.txt (3 kB)  

Drápala J., Morávková Z., Vrbický J., Dostál V., Sidorov E.V.
THE THEORETICAL ASPECTS OF CRYSTALLIZATION IN TERNARY ALLOYS AND THE CHARACTER OF SEGREGATION PROCESSES AT EQUILIBRIUM AND NON-EQUILIBRIUM SOLIDIFICAT
Keywords: ternary system|crystallization|liquidus|solidus|segregation coefficient|
No 1 (2007), p. 76-84
  mag09.pdf (256 kB)
mag09_eng.txt (2 kB)  

Isayev O., Nosochenko O., Kislitsa V.
DEVELOPMENT THE CONTINUOUS CASTING TECHNOLOGY OF Nb-CONTENT STEEL GRADES FOR INTERNAL SLABS AND PLATES QUALITY IMPROVEMENT
Keywords: line pipe grades of steel|Nb-content|tundish|inclusions|residual time|refining|
No 1 (2007), p. 85-93
  mag10.pdf (347 kB)
mag10_eng.txt (3 kB)  

Purmenský J., Foldyna V.
DEVELOPMENT OF LOW ALLOY AND MODIFIED CHROMIUM STEELS STRENGTHENED BY NANOPARTICLES
Keywords: Creep resisting steels|structural stability|nanoparticles|
No 1 (2007), p. 94-100
  mag11.pdf (480 kB)
mag11_eng.txt (3 kB)  

Hernas A., Herian J., Wylaź P.
MICROSTRUCTURE AND PROPERTIES OF HOT ROLLED 42CrMo4 STEEL CHARGE AND RINGS
Keywords: Steel rings|heterogeneity|microstructure|hardness|modification of process technology|
No 1 (2007), p. 101-108
  mag12.pdf (2 MB)
mag12_eng.txt (2 kB)  

Pascu D.-R., Pascu M.
STRUCTURAL HARDENING OF THE G20Mn6 CAST STEEL WITHIN THE CONSTRUCTION OF THE WELDED SAFETY LOCKS FROM THE RAILWAY CONTAINERS
Keywords: safety lock|G20Mn6 steel|hardening|structural examination|mechanical testing|heat treatment|
No 1 (2007), p. 109-116
  mag13.pdf (1 MB)
mag13_eng.txt (3 kB)  

Lejček P., Janovec J., Konečná R.
NANOSEGREGATION PHENOMENA AT GRAIN BOUNDARIES OF METALLIC MATERIALS
Keywords: segregation|grain boundaries|prediction|thermodynamics|ferrite alloys|
No 1 (2007), p. 117-130
  mag14.pdf (1 MB)
mag14_eng.txt (3 kB)