On Bainite Transformation Kinetics and Mechanism

2007 ◽  
Vol 539-543 ◽  
pp. 3018-3023 ◽  
Author(s):  
Si Xin Zhao ◽  
Wei Wang ◽  
Da Li Mao
Keyword(s):  
Experimental Data ◽  
Growth Rates ◽  
Bainitic Ferrite ◽  
Transformation Kinetics ◽  
Alloying Element ◽  
Transformation Mechanism ◽  
Bainite Transformation ◽  
Steel Composition ◽  
Slowing Down ◽  
Theoretical Results

The platelike bainitic ferrite growth rates were calculated by two modified diffusional models. Good agreements between experimental and theoretical results are found in Fe-0.59C wt.%, Fe-0.81C wt.% and Fe-0.478C-4.87Ni wt.% alloys. A slowing down effect due to the alloying element Mo is emphasized in Fe-0.69C-1.8Ni-0.8Mo wt.% alloy. However, the experimental data are lower than theoretical ones about two orders in Fe-C-8.7Ni wt.% alloys. According to the discussion of the results, it is suggested that the bainite transformation mechanism may relates to steel composition and transformation temperature.

Slow Bainite: an Opportunity to Determine the Carbon Content of the Bainitic Ferrite during Growth

2011 ◽  
Vol 172-174 ◽  
pp. 111-116 ◽  
Author(s):  
Francisca García Caballero ◽  
Michael K. Miller ◽  
Carlos García-Mateo
Keyword(s):  
Solid Solution ◽  
Carbon Content ◽  
Atom Probe Tomography ◽  
Early Stage ◽  
Bainitic Ferrite ◽  
Atom Probe ◽  
Transformation Kinetics ◽  
Bainite Transformation ◽  
Parent Austenite ◽  
Kinetics Of

The amount of carbon in solid solution in bainitic ferrite at the early stage of transformation has been directly determined by atom probe tomography at 200 °C, taking advantage of the extremely slow transformation kinetics of a novel nanocrystalline steel. Results demonstrated that the original bainitic ferrite retains much of the carbon content of the parent austenite providing strong evidence that bainite transformation is essentially displacive in nature.

scholarly journals Diagnostics of the bainite transformation mechanism and the effect of normalizing and tempering on the hardness and microstructure of the new Cr-Mo-V-Ti steel for operation at elevated temperature

2018 ◽  
Vol 182 ◽  
pp. 02006
Author(s):  
Zdzisław Ławrynowicz
Keyword(s):  
High Speed ◽  
Power Plants ◽  
Elevated Temperatures ◽  
Thermal Power ◽  
Bainitic Ferrite ◽  
Residual Austenite ◽  
Low Alloy Steels ◽  
Transformation Mechanism ◽  
Bainite Transformation ◽  
Conventional Heat Treatment

The Cr-Mo-V-Ti based low alloy steels are widely used in thermal power plants because of their ability to withstand elevated temperatures and high pressure under continuous service. In the present work conventional heat treatment like normalizing and tempering of the alloys has been performed. The material used in this study was the laboratory prepared experimental low alloy Cr-Mo-V-Ti steel. Samples were austenitized at 980oC for 0.5 hour air cooled and tempered at 500, 550, 600, 650, 700 and 750oC for 1 hour. Mechanism of bainite transformation has been studied in Fe-C-Cr-Mo-V-Ti steel using high speed dilatometry. These experimental data indicate that bainitic ferrite forms by a displacive transformation mechanism, but soon afterwards, excess of carbon is partitioned into the residual austenite. The changes observed in the microstructure of the steel tempered at the higher temperature, i.e. 750°C were more advanced than those observed at the temperature of 500°C. Performed microstructural investigations have shown that the degradation of the microstructure of the examined steel was mostly connected with the processes of recovery and polygonization of the matrix, disappearance of lath bainitic microstructure and the growth of the carbides. The magnitude of these changes depended on the temperature of tempering.

scholarly journals Study on Kinetics of Transformation in Medium Carbon Steel Bainite at Different Isothermal Temperatures

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2721
Author(s):  
Wei Pei ◽  
Wei Liu ◽  
Yue Zhang ◽  
Rongjian Qie ◽  
Aimin Zhao
Keyword(s):  
Bainitic Ferrite ◽  
Isothermal Transformation ◽  
Medium Carbon Steel ◽  
Transformation Kinetic ◽  
Transformation Kinetics ◽  
Bainite Transformation ◽  
Medium Carbon ◽  
Microstructure And Properties ◽  
Treatment Processes ◽  
Kinetics Of

Ultra-fine carbide-free bainitic (UCFB) steel, also known as nano-bainite (NB) steel, is composed of bainitic ferrite laths with nanoscale thickness and carbon-rich film-like retained austenite located between laths. The bainite transformation kinetic model can accurately describe the bainite transformation kinetics in conventional austempering (CA) processes based on the shear mechanism combined with the dilatometer test. UCFB steels with medium and high carbon composition are designed in this work to systematically study the transformation kinetics of bainite, and the evolution of its microstructure and properties, and reveal the influence of heat treatment processes on the microstructure and properties the UCFB steels. The results show that the activation energy for BF nucleation decreases during the CA process and isothermal transformation temperature decreases. The bainite transformation is first nucleated at the grain boundaries, and then nucleated at the newly formed bainitic ferrite/austenite interface.

Kinetics of the Crystallization of Potassium Sulfate

1993 ◽  
Vol 58 (8) ◽  
pp. 1848-1854 ◽  
Author(s):  
Miroslav Karel ◽  
Jaroslav Nývlt
Keyword(s):  
Experimental Data ◽  
Crystal Growth ◽  
Growth Rates ◽  
Potassium Sulfate ◽  
Kinetics Of

The kinetics of the crystallization of potassium sulfate has been determined using the MSMPR technique. Values of the nucleation and crystal growth rates evaluated from the experimental data are compared with the corresponding literature data.

scholarly journals Continuous Cooling Transformation Behaviour and Bainite Transformation Kinetics of 23CrNi3Mo Carburised Steel

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 48
Author(s):  
Wenjun Song ◽  
Min Lei ◽  
Mingpan Wan ◽  
Chaowen Huang
Keyword(s):  
Phase Transformation ◽  
Volume Fraction ◽  
Austenite Formation ◽  
Steel Matrix ◽  
Transformation Kinetics ◽  
Bainite Transformation ◽  
Continuous Cooling ◽  
The Matrix ◽  
Dimensional Growth ◽  
Kinetics Of

In this study, the phase transformation behaviour of the carburised layer and the matrix of 23CrNi3Mo steel was comparatively investigated by constructing continuous cooling transformation (CCT) diagram, determining the volume fraction of retained austenite (RA) and plotting dilatometric curves. The results indicated that Austenite formation start temperature (Ac1) and Austenite formation finish temperature (Ac3) of the carburised layer decreased compared to the matrix, and the critical cooling rate (0.05 °C/s) of martensite transformation is significantly lower than that (0.8 °C/s) of the matrix. The main products of phase transformation in both the carburised layer and the matrix were martensite and bainite microstructures. Moreover, an increase in carbon content resulted in the formation of lamellar martensite in the carburised layer, whereas the martensite in the matrix was still lath. Furthermore, the volume fraction of RA in the carburised layer was higher than that in the matrix. Moreover, the bainite transformation kinetics of the 23CrNi3Mo steel matrix during the continuous cooling process indicated that the mian mechanism of bainite transformation of the 23CrNi3Mo steel matrix is two-dimensional growth and one-dimensional growth.

The Compliance of Solid, Wide-Faced Spur Gears

1990 ◽  
Vol 112 (4) ◽  
pp. 590-595 ◽  
Author(s):  
J. H. Steward
Keyword(s):  
Experimental Data ◽  
Contact Line ◽  
Load Distribution ◽  
3D Model ◽  
Spur Gear ◽  
Point Load ◽  
Spur Gears ◽  
Line Load ◽  
Gear Teeth ◽  
Theoretical Results

In this paper, the requirements for an accurate 3D model of the tooth contact-line load distribution in real spur gears are summarized. The theoretical results (obtained by F.E.M.) for the point load compliance of wide-faced spur gear teeth are set out. These values compare well with experimental data obtained from tests on a large spur gear (18 mm module, 18 teeth).

Monte Carlo backscattering yield (BY) calculations applying continuous slowing down approximation (CSDA) and experimental data

Vacuum ◽  
2007 ◽  
Vol 82 (2) ◽  
pp. 201-204 ◽  
Author(s):  
L. Zommer ◽  
A. Jablonski ◽  
G. Gergely ◽  
S. Gurban
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Slowing Down

Explanation of the Influence of Inflow Air Content on the Lift of Cavitating Hydrofoils

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Eduard Amromin
Keyword(s):  
Experimental Data ◽  
Theoretical Study ◽  
Lift Coefficient ◽  
Cavity Surface ◽  
Air Bubbles ◽  
Incoming Flow ◽  
Fluid Density ◽  
Air Content ◽  
Theoretical Results ◽  
Good Agreement

According to several known experiments, an increase of the incoming flow air content can increase the hydrofoil lift coefficient. The presented theoretical study shows that such increase is associated with the decrease of the fluid density at the cavity surface. This decrease is caused by entrainment of air bubbles to the cavity from the surrounding flow. The theoretical results based on such explanation are in a good agreement with the earlier published experimental data for NACA0015.

scholarly journals C-VCalculations in CdS/CdTe Thin Films Solar Cells with aCdSxTe1-xInterlayer

2013 ◽  
Vol 2013 ◽  
pp. 1-4
Author(s):  
A. Gonzalez-Cisneros ◽  
F. L. Castillo-Alvarado ◽  
J. Ortiz-Lopez ◽  
G. Contreras-Puente
Keyword(s):  
Experimental Data ◽  
Thin Films ◽  
Solar Cells ◽  
Photovoltaic Cells ◽  
Cdte Film ◽  
Vapor Transport ◽  
Cdte Solar Cells ◽  
Cdte Thin Films ◽  
Cds Film ◽  
Theoretical Results

In CdS/CdTe solar cells, chemical interdiffusion at the interface gives rise to the formation of an interlayer of the ternary compoundCdSxCdTe1-x. In this work, we evaluate the effects of this interlayer in CdS/CdTe photovoltaic cells in order to improve theoretical results describing experimentalC-V(capacitance versus voltage) characteristics. We extended our previous theoretical methodology developed on the basis of three cardinal equations (Castillo-Alvarado et al., 2010). The present results provide a better fit to experimental data obtained from CdS/CdTe solar cells grown in our laboratory by the chemical bath deposition (for CdS film) and the close-spaced vapor transport (for CdTe film) techniques.

scholarly journals Verification of Brittle Fracture Criteria for Bimaterial Structures

2014 ◽  
Vol 8 (1) ◽  
pp. 44-48
Author(s):  
Grzegorz Mieczkowski ◽  
Krzysztof Molski
Keyword(s):  
Experimental Data ◽  
Composite Materials ◽  
Cyclic Loading ◽  
Brittle Fracture ◽  
Axial Loading ◽  
Loading Conditions ◽  
Fracture Criteria ◽  
Interfacial Cracks ◽  
Theoretical Results ◽  
Brittle Fracture Criteria

Abstract The increasing application of composite materials in the construction of machines causes strong need for modelling and evaluating their strength. There are many well known hypotheses used for homogeneous materials subjected to monotone and cyclic loading conditions, which have been verified experimentally by various authors. These hypotheses should be verified also for composite materials. This paper provides experimental and theoretical results of such verifications for bimaterial structures with interfacial cracks. Three well known fracture hypotheses of: Griffith, McClintock and Novozhilov were chosen. The theoretical critical load values arising from each hypotheses were compared with the experimental data including uni and multi-axial loading conditions. All tests were carried out with using specially prepared specimens of steel and PMMA.

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