Kinetics of decomposition of the supercooled austenite of 32G2 steel during continuous and interrupted accelerated quenching

1985 ◽  
Vol 27 (3) ◽  
pp. 174-177
Author(s):  
Yu. P. Gul' ◽  
V. S. Chmeleva ◽  
M. F. Evsyukov ◽  
Yu. V. Yakubovich ◽  
V. K. Chernykh
Keyword(s):  
Supercooled Austenite ◽  
Kinetics Of Decomposition ◽  
Kinetics Of

scholarly journals Investigation of the decay kinetics of austenite with continuous cooling K76F steel for wide-gauge railway rails

2018 ◽  
pp. 317-327
Author(s):  
A.I. Babachenko ◽  
A.A. Kononenko ◽  
A.M. Khulin
Keyword(s):  
Heat Treatment ◽  
High Strength ◽  
Operational Reliability ◽  
Supercooled Austenite ◽  
Decay Kinetics ◽  
Iron And Steel ◽  
Continuous Cooling ◽  
Kinetics Of Decomposition ◽  
Dilatometric Studies ◽  
Kinetics Of

The aim of the work is to study the kinetics of decomposition of supercooled austenite with continuous cooling of steel for railway rails with a high content of manganese and micro-alloyed vanadium. The relevance of the work is the need to determine the possibility of producing rails from K76 F steel according to foreign standards, in particular EN 13674-1-2011. During the research, a thermo-kinetic diagram was constructed with different cooling rates for samples of K76F steel heated by the heating mode for quenching the rails in an induction unit at the heat treatment site at Azovstal Iron and Steel Works. Dilatometric studies have shown that when samples are heated at a rate of 300С/min in steel for railway rails, polymorphic  -transformation begins at temperature 7350С (Ас1), ends at 7600С (Ас3). It is established that the temperatures of the beginning and completion of the formation of ferrite, perlite and bainite decrease with increasing cooling rate. With an increase in the rate of cooling, the morphology changes and the dispersion of perlite increases - from the middle plate of frequent perlite to highly dispersed sorbitol structures and quenching troostite. It was concluded that in the studied steel grade K76F with 0.80%С, 0.25%Si, 0.97%Mn, 0.055%V, it is impossible to achieve hardness above 400НВ without the formation of bainite. For the manufacture of high-strength rails of category R400HT EN 13674-1-2011, it is necessary to create steel of a new chemical composition. It is shown that it is possible to develop grounded reinforcing heat treatment mode and to increase the operational reliability of rails by defining critical points and studying the kinetics of decomposition of supercooled austenite with continuous cooling of steel.

scholarly journals Mathematical Modelling of Kinetics of Decomposition of the Supercooled Austenite in Alloyed Steels

2017 ◽  
Vol 39 (8) ◽  
pp. 1051-1068 ◽  
Author(s):  
V. V. Kaverynsky ◽  
◽  
A. I. Trotsan ◽  
Z. P. Sukhenko ◽  
◽  
...  
Keyword(s):  
Mathematical Modelling ◽  
Supercooled Austenite ◽  
Kinetics Of Decomposition ◽  
Kinetics Of

Kinetics and Mechanism of Decomposition of 1,3-Bis(4-methylphenyl)triazene Catalyzed with Substituted Benzoic Acids in 25% Aqueous Methanol-General or Specific Catalysis?

1994 ◽  
Vol 59 (9) ◽  
pp. 2029-2041
Author(s):  
Oldřich Pytela ◽  
Taťjana Nevěčná
Keyword(s):  
Benzoic Acids ◽  
Hammett Equation ◽  
Aqueous Methanol ◽  
Mechanism Of Decomposition ◽  
Kinetics Of Decomposition ◽  
Independent Variable ◽  
Amino Derivatives ◽  
Substituted Benzoic Acids ◽  
The Individual ◽  
Kinetics Of

The kinetics of decomposition of 1,3-bis(4-methylphenyl)triazene catalyzed with 13 substituted benzoic acids of various concentrations have been measured in 25 vol.% aqueous methanol at 25.0 °C. The rate constants observed (297 data) have be used as values of independent variable in a series of models of the catalyzed decomposition. For the catalytic particles were considered the undissociated acid, its conjugated base, and the proton in both the specific and general catalyses. Some models presumed formation of reactive or nonreactive complexes of the individual reactants. The substituent effect is described by the Hammett equation. The statistically best model in which the observed rate constant is a superposition of a term describing the dependence on proton concentration and a term describing the dependence on the product of concentrations of proton and conjugated base is valid with the presumption of complete proton transfer from the catalyst acid to substrate, which has been proved. The behaviour of 4-dimethylamino, 4-amino, and 3-amino derivatives is anomalous (lower catalytic activity as compared with benzoic acid). This supports the presumed participation of conjugated base in the title process.

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