Národní úložiště šedé literatury Nalezeno 571 záznamů.  začátekpředchozí535 - 544dalšíkonec  přejít na záznam: Hledání trvalo 0.01 vteřin. 
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).
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.
Long-time oxidation of carbon steel grade 55 and bearing steel LH15 at high temperatuers
Adamaszek, K. ; Jurasz, Z. ; Kučera, Jaroslav
High temperature oxidation of the cylindrical samples (f = 10 diameter and l = 15mm length) made of carbon steel grade 55 and bearing steel LH15 has been performed in air in temperature range 940ů1100°C and for various times. Using the experimentally measured thickness of scale layers, the oxidation process of mentioned steels have been compared.
Problematika posuzování a význam vlivu teploty na interakční součinitele v železe a oceli
Stránský, Karel ; Kučera, Jaroslav ; Million, Bořivoj ; Šenberger, J.
Daný příspěvek se týká vlivu teploty na termodynamické .epsilon.ic a difuzní .beta.ic interakční koeficienty v .gamma.Fe a v austenitizačních ocelích. Studium souboru vlastních a publikovaných dat ukázalo, že uvedené interakční koeficienty jsou navzájem úměrné. V rámci chyb měření platí že .beta.ic = .epsilon.ic.
Decarburization of Fe-C-Cr-Mn-Si steels at high temperatures in ambient air
Hajduga, M. ; Glowacki, J. ; Kučera, Jaroslav
The measured values of carbon concentration N(C,x,t) make it possible to get the diffusivities D(C) and hardness values HV(x,t) the coefficients D(HV). The values D(HV)=D(C) in the case that HV(x,t) values are dierectly proportional to N(C,x,t). It is shown that the fatigue limit of carbon steels may calculated from the relation ńëa=0.235HV05.

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