National Repository of Grey Literature 10 records found  Search took 0.01 seconds. 
On the redistribution of aluminium and carbon in the weld joints of steels in the temperature range 500-1100oC (1,15 wt.% Al)
Stránský, K. ; Million, Bořivoj ; Foret, R. ; Michalička, Petr ; Rek, A.
Measurements of Al, Cr, Fe, Ni, C redistribution in welded joints of unalloyed 12050+1,15Al steel and high alloyed Cr-Ni steel in temperature range 500-1100oC were realised by means of analytical complex JEOL JXA 8600/KEVEX. The C, Al, Cr, Fe, Ni diffusion coefficients were established and the relation among diffusion coefficients were discused.
Long-Time Oxidation of gammaFe and LH15 Steel at High Temperatures in Air
Kučera, Jaroslav ; Adamaszek, K. ; Jurasz, Z.
The results of surface oxidation and decarburizatin of (Fe, C, Mn, Si, Cr, Ni) steels are reported. The oxidation anneals were carried out at temperatures T = 940, 980, 1020, 1060, 1100 oC. The time course of Fe and of steels oxidation is expressed by parabolic law. The surface oxidation is accompanied by decarburization of surface steel layers. The evaluation of measured carbon concentration profiles N(C,x,t) yields diffusion coefficients D(C,T). Oxidation coefficients kp(T) are linearly proportional to D(C,T).
A new construction of rotor of helium expansion turbine
Dupák, J. ; Hanzelka, P. ; Michalička, Petr ; Tuček, L. ; Ustohal, V.
The aim of our work was to develop a rotor of the expansion turbine designed for a helium liquefier that would enable to operate in different modes and to achieve the desired effctiveness at same time. For meeting these requirements the rotor should enable precise operation of the turbine in the range 140000 to 350000 rpm at minimum heat flow to the low-temperature part of the turbine.
THE INFLUENCE OF HIGH TEMPERATURES ON THE DIRECTION OF CARBON DIFFUSION FLUX IN STEEL WELDMENTS
Kučera, Jaroslav ; Michalička, Petr ; Million, Bořivoj ; Rek, A. ; Stránský, K.
The redistribution of carbon in steel weldments heated at temperatures situated in the range 500 °C up to 1100 °C is reported. The sandwich-like specimens used for experiments were made from the steels A .IDENT. (ČSN 17242) and K .IDENT. (P91). It was stated that at low temperatures (500-750 °C) the carbon diffusion flux is directed from the steel A into the steel K and at high temperatures from K into A.
OXIDATION OF Fe AND STEELS AT HIGH TEMPERATURES
Kučera, Jaroslav ; Adamaszek, K. ; Hajduga, M.
The results of surface oxidation and decarburization of (Fe, C, Mn, Si, Cr, Ni) steels are reported. The oxidation anneals were carried out at temperatures T = 940, 980, 1020, 1060, 1100 °C. The time course of Fe and of steels oxidation is expressed by parabolic law l = kp . The surface oxidation is accompanied by decarburization of surface steel layers. The evaluation of measured carbon concentration profiles N(C,x,t) yields diffusion coefficients D(C,T). Oxidation coefficients kp(T) are linearly proportional to D(C,T).
LONG-TIME OXIDATION OF .gamma.Fe AND LH15 STEEL AT HIGH TEMPERATURES IN AIR
Kučera, Jaroslav ; Adamaszek, K. ; Jurasz, Z.
The investigation of long-time oxidation of gFe and of low alloyed steel LH15 in ambient air is reported. The specimens of gFe had the form of wires with diameter f = 3.0 mm. The relative weight gain Dw/w of these specimens grows in the course of oxidation anneal due to the oxides FeO, Fe3O4, Fe2O3 formation. The weight gain is stopped at very long time period t of oxidation anneals. This phenomenon is denoted as saturation effect. The same effect was observed in the case of oxidation of specimens made from low alloyed steel LH15. The specimens had the form of cylinders with diameter .fi. = 10 mm.
Simultaneous diffusion of aluminium, carbon, chromium, iron and nickel in steel weldments at temperature interval 500 to 1100°C
Stránský, K. ; Million, Bořivoj ; Foret, R. ; Rek, A. ; Michalička, Petr
In this paper results of measurements of simultaneous diffusion of aluminium, carbon, chromium, iron and nickel in welded joints of unalloyed 12050+Al steel and high alloy austenitic chromium-nickel steel are presented.
On the redistribution of aluminium and carbon in a weld joints of steels in the temperature range 500-1100°C
Stránský, K. ; Million, Bořivoj ; Foret, R. ; Michalička, Petr ; Rek, A.
In this paper an original results of aluminium, chromium, iron,nickel and carbon redistribution in welded joints of unalloyed 12050+Al steel and high alloy austenitic chromium-nickel steel are presented.
Chemical heterogeneity of ductile iron - models and measurements
Kavička, F. ; Stránský, K. ; Dobrovská, J. ; Dobrovská, V. ; Heger, J. ; Million, Bořivoj ; Rek, A.
The paper deals with an original method of measurements of elements microheterogeneity in the structure of ductile iron and with the possibilities of this new method.
A contribution to the redistribution of aluminium in a weld joints of steels
Stránský, K. ; Million, Bořivoj ; Foret, R. ; Michalička, Petr ; Rek, A.
An original results of redistribution in welded joints of unalloyed 12050+Al steel and high alloy austenitic chromium-nickel steel are presented. The diffusion coefficients of Al, Cr, Fe and Ni were established and the relation among diffusion coefficients was discussed.

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