700
A. E. Stetsko and Y. T. Stetsko
in the thickness direction. The results showed that the sheet of iron in the direction of
thickness after discoloration formed is of three layers: layer (ferrite phase) that was
near the surface; layer (cementite phase), which was located between (ferrite phase
+ cementite phase + ferrite phase) + (graphite phase) layers; and layer between
(cementite phase + ferrite phase) + (graphite phase), which was at the center of
the sample. The thickness of decarburization layer (ferrite phase + cementite phase)
showed a nice linear correlation to the square root of the decarburization time. A
staircase type during discoloration was the carbon gradient in the iron sheet in the
thickness direction. The carbon migration in the iron sheet is contained of stable
carbon decomposition and free carbon diffusion. The carbon content in the center of
iron sheet was influenced by the time or temperature of decarburization. The carbon
migration at S 2 iron stage was the control stage of the entire bleaching process.
Researchers conducted studies [2] of gas dispersion of high-alloy stainless steel to
the growth surface hardness as general mechanical surface characteristics. It has been
observed that the growth of chromium-rich carbides during the transfer of carbon
to steel causes precipitation on the surface but reduces the chromium content of the
solid solution. For this reason to keep a good corrosion resistance in the carbonated layer, it is obvious to optimize the stainless steel composition and the mintage
process. Thermodynamic calculations are first used to find optimal parameters to
maintain the highest Cr and Mo contents in the austenitic solid solution. A good
correspondence between the calculated and experimental values was observed for
martensitic stainless steel at 955 and 980 °C.
Published data [3] on carbon diffusion in austenite is calculated by the estimation in full austenitic range and then to be extrapolated to the temperature range
of phase transformation. Data are limited to temperatures above 750 °C. In this
study, new experiments are conducted to determine the carbon diffusion coefficient
in austenite at temperatures up to 500 °C. Carburization experiments are completed
in the austenitic range for a Fe–Mn–C and a Fe–Ni alloy. This method is first validated on the Fe–C–Mn steel. Carburization experiments are implemented on a Fe–Ni
alloy at a temperature from 900 to 500 °C with step 100 °C.
The boronization and carburization of fine-grained superplastic stainless
steel is studied in [4]. New experimental consequences on fine-grained
Ti88.5Al4.5V3Fe2Mo2 were obtained. The diffusion of boron into steel superplastic
alloy was scrutinized.
In [5], we can see prestraining of plastic accelerates the diffusion of carbon and
boron. We apply boron-cemented layers with a homogeneous structure and enriched
physicochemical properties hardened with significantly grained boron carbides.
In [6], the technological facet of boriding processe was done taking into account
the pros and cons of each method. The influences of the boriding technique on the
microstructure of borided materials have been indicated. Consideration in this part
was given to the powder-pack processes, electrochemical boronizing in borax to the
gas boronizing with the use of boron halides or boranes.
A. E. Stetsko and Y. T. Stetsko
in the thickness direction. The results showed that the sheet of iron in the direction of
thickness after discoloration formed is of three layers: layer (ferrite phase) that was
near the surface; layer (cementite phase), which was located between (ferrite phase
+ cementite phase + ferrite phase) + (graphite phase) layers; and layer between
(cementite phase + ferrite phase) + (graphite phase), which was at the center of
the sample. The thickness of decarburization layer (ferrite phase + cementite phase)
showed a nice linear correlation to the square root of the decarburization time. A
staircase type during discoloration was the carbon gradient in the iron sheet in the
thickness direction. The carbon migration in the iron sheet is contained of stable
carbon decomposition and free carbon diffusion. The carbon content in the center of
iron sheet was influenced by the time or temperature of decarburization. The carbon
migration at S 2 iron stage was the control stage of the entire bleaching process.
Researchers conducted studies [2] of gas dispersion of high-alloy stainless steel to
the growth surface hardness as general mechanical surface characteristics. It has been
observed that the growth of chromium-rich carbides during the transfer of carbon
to steel causes precipitation on the surface but reduces the chromium content of the
solid solution. For this reason to keep a good corrosion resistance in the carbonated layer, it is obvious to optimize the stainless steel composition and the mintage
process. Thermodynamic calculations are first used to find optimal parameters to
maintain the highest Cr and Mo contents in the austenitic solid solution. A good
correspondence between the calculated and experimental values was observed for
martensitic stainless steel at 955 and 980 °C.
Published data [3] on carbon diffusion in austenite is calculated by the estimation in full austenitic range and then to be extrapolated to the temperature range
of phase transformation. Data are limited to temperatures above 750 °C. In this
study, new experiments are conducted to determine the carbon diffusion coefficient
in austenite at temperatures up to 500 °C. Carburization experiments are completed
in the austenitic range for a Fe–Mn–C and a Fe–Ni alloy. This method is first validated on the Fe–C–Mn steel. Carburization experiments are implemented on a Fe–Ni
alloy at a temperature from 900 to 500 °C with step 100 °C.
The boronization and carburization of fine-grained superplastic stainless
steel is studied in [4]. New experimental consequences on fine-grained
Ti88.5Al4.5V3Fe2Mo2 were obtained. The diffusion of boron into steel superplastic
alloy was scrutinized.
In [5], we can see prestraining of plastic accelerates the diffusion of carbon and
boron. We apply boron-cemented layers with a homogeneous structure and enriched
physicochemical properties hardened with significantly grained boron carbides.
In [6], the technological facet of boriding processe was done taking into account
the pros and cons of each method. The influences of the boriding technique on the
microstructure of borided materials have been indicated. Consideration in this part
was given to the powder-pack processes, electrochemical boronizing in borax to the
gas boronizing with the use of boron halides or boranes.