scholarly journals The Kinetics of Phase Transition of Austenite to Ferrite in Medium-Carbon Microalloy Steel

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1986
Author(s):  
Liushun Wu ◽  
Kunlong Liu ◽  
Yun Zhou
Keyword(s):  
Phase Transition ◽  
Volume Fraction ◽  
High Strength ◽  
Effect Of Temperature ◽  
Avrami Equation ◽  
Validation Data ◽  
Medium Carbon ◽  
Hot Rolled ◽  
Kinetics Of ◽  
Transition Kinetic

To reduce energy and resource consumption, high-strength hot-rolled rebars with yield strengths of ≥400 MPa (HRB500) and ≥500 MPa (HRB600) have been designed and produced in recent years. Optimizing the microstructure in the steel to improve strength necessitates determining the kinetics of the phase transition of austenite to polygonal ferrite. Therefore, in the study, the effect of temperature and holding time on the volume fraction of ferrite is investigated in HRB500 and HRB600 steels. Experimental results show that the ferrite percentage initially increases with an increase in temperature and then decreases as the temperature increases from 600 to 730 °C. The optimum temperature range is 680–700 °C for HRB500 steel and 650–680 °C for HRB600 steel. Based on the Johnson–Mehl–Avrami equation, phase transition kinetic models are established. Model predictions are consistent with the validation data. Thus, this study establishes a reference for studying ferrite formation during cooling.

Temperature Effect on the Two-Dimensional Phase Transition Kinetics of Adenine Adsorbed at the Hg Electrode/Aqueous Solution Interface

2003 ◽  
Vol 68 (8) ◽  
pp. 1407-1419 ◽  
Author(s):  
Claudio Fontanesi ◽  
Roberto Andreoli ◽  
Luca Benedetti ◽  
Roberto Giovanardi ◽  
Paolo Ferrarini
Keyword(s):  
Phase Transition ◽  
Aqueous Solution ◽  
Phase Change ◽  
Temperature Effect ◽  
Transition Rate ◽  
Effect Of Temperature ◽  
Two Dimensional ◽  
Solution Interface ◽  
Phase Transition Kinetics ◽  
Kinetics Of

The kinetics of the liquid-like → solid-like 2D phase transition of adenine adsorbed at the Hg/aqueous solution interface is studied. Attention is focused on the effect of temperature on the rate of phase change; an increase in temperature is found to cause a decrease of transition rate.

scholarly journals Application of Computer Simulation to Study the Features of the Austenite Isothermal Transformation in Steels

2019 ◽  
Vol 1 (1) ◽  
pp. 1
Author(s):  
Yu.V. Yudin ◽  
M.V. Maisuradze ◽  
A.A. Kuklina ◽  
P.D. Lebedev
Keyword(s):  
Phase Transition ◽  
Computer Simulation ◽  
Solid State ◽  
Isothermal Transformation ◽  
Avrami Equation ◽  
Kinetic Curves ◽  
Simulation Results ◽  
Experimental Kinetics ◽  
Kinetics Of ◽  
New Phase

An algorithm was developed for the simulation of a phase transition in solid state whichmakes it possible to obtain the kinetic curves of transformation under different initialconditions (the number and arrangement of new phase nuclei, the distance betweenthe nearest nuclei). The simulation results were analyzed using the Kolmogorov-Johnson-Mehl-Avrami equation and the corresponding coefficients were determined.The correlation between the simulation results and the experimental kinetics of theaustenite isothermal transformation in alloyed steels was shown.

Low C High Mn Cold Rolled TWIP Steel: Kinetics of Isothermal Recrystallization

2012 ◽  
Vol 706-709 ◽  
pp. 2181-2186 ◽  
Author(s):  
Tulio M.F. Melo ◽  
Érica Ribeiro ◽  
Lorena Dutra ◽  
Dagoberto Brandão Santos
Keyword(s):  
Automobile Industry ◽  
Twip Steel ◽  
Volume Fraction ◽  
Microstructural Analysis ◽  
High Strength ◽  
Specific Weight ◽  
Carbon Steels ◽  
Cold Rolled ◽  
Increasing Demand ◽  
Kinetics Of

The increasing demand, mainly from the automobile industry, for materials which combine high strength, high ductility and low specific weight makes steels with the TWIP (TWinning Induced Plasticity) effect a promising material to meet these requirements. This work aimed to study the kinetics of isothermal recrystallization of a TWIP steel (C-0.06%, Mn-25%, Al-3%, Si-2%, and Ni-1%) after cold rolling. The steel was hot and cold-rolled and then annealed at 700°C with soaking times ranging from 10 to 7200 s. Microstructural analysis was performed using light (LM) and scanning electron microscopy (SEM). Furthermore, quantitative metallography was performed in order to evaluate the recrystallized volume fraction and grain size. A JMAK based model was applied to describe the nucleation grain growth process. The restoration of the steel was also evaluated by microhardness tests. A complete recrystallization after 7200 s at 700°C was observed. It was found that with increasing annealing times, the recrystallized volume fraction also increases, while the nucleation and growth rates decrease, in agreement with the results for plain carbon steels.

Study on Hot Deformation Behavior of 97# High Strength Rod

2012 ◽  
Vol 159 ◽  
pp. 322-325
Author(s):  
Hong Bin Li ◽  
Fang Fang
Keyword(s):  
Hot Deformation ◽  
Deformation Behavior ◽  
Static Recrystallization ◽  
Volume Fraction ◽  
High Strength ◽  
Avrami Equation ◽  
Recrystallization Process ◽  
Hot Deformation Behavior ◽  
Deformation Behaviors ◽  
Gleeble 3500

the hot deformation behaviors of 97# High Strength Rod was investigated through double-hit compression experiments using Gleeble 3500 thermal-mechanical similar within the temperature range of 850~1100°C, the strain rate of 5 s-1 and the interval range of 1-100s, the softening fractiong at different pass interval and deforming temperature was determined and analyzed. The results show that when pass intervals is the same, as deformation temperature increase, the volume fraction of static recrystallization of 97# High Strength Rod increases and the recrystallization process is enchanced. Activation energy of austenite static recrystallization of 97# High Strength Rod is 100.476 kJ/mol. The kinetic equation of static recrystallization of 97# High Strength Rod by avrami equation wan obtained.

The Kinetics of Spinel Crystallization from a High-Level Waste Glass

1996 ◽  
Vol 465 ◽  
Author(s):  
J. G. Reynolds ◽  
P. Hrma
Keyword(s):  
Volume Fraction ◽  
Treatment Time ◽  
Waste Glass ◽  
High Level Waste ◽  
Avrami Equation ◽  
Kinetic Coefficients ◽  
High Level Nuclear Waste ◽  
Isothermal Heat Treatments ◽  
High Level ◽  
Kinetics Of

ABSTRACTThe kinetics of spinel crystallization from a molten high-iron simulated high-level nuclear waste glass was studied using isothermal heat treatments. Optical microscopy with image analysis was used to measure volume fraction of spinel as a function of heat treatment time and temperature. The Johnson-Mehl-Avrami equation was fitted to data to determine kinetic coefficients for spinel crystallization. The liquidus temperature and Avrami number are TL = 1337K and n = 1.5.

Effect of Coiling Temperature on Kinetics of Austenite Formation in Cold Rolled Advanced High Strength Steels

2012 ◽  
Vol 706-709 ◽  
pp. 2112-2117 ◽  
Author(s):  
R.R. Mohanty ◽  
O.A. Girina
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Continuous Heating ◽  
Austenite Formation ◽  
Continuous Annealing ◽  
Hard Material ◽  
Low Carbon ◽  
Coiling Temperature ◽  
Hot Rolled ◽  
Kinetics Of

A systematic experimental investigation was conducted using lab processed low carbon 0.08C-2.0Mn-Cr-Mo steel microalloyed with Ti/Nb to evaluate the influence of initial hot-rolled microstructures on the kinetics of austenite formation and decomposition after cold-rolling and subsequent annealing. Coiling temperature as a major hot rolling parameter was used to obtain different types of hot-rolled microstructures. Dilatometer and continuous annealing simulator were employed for austenite formation studies and annealing simulations, respectively. It was found that the coiling temperature affects the processes occurring during heat treatment in continuous annealing lines of full hard material: ferrite recrystallization, austenite formation during continuous heating and austenite decomposition during cooling. A decrease in coiling temperature accelerates the recrystallization of ferrite and nucleation of austenite, which results in formation of refined ferrite-martensite structure. The effect of initial hot rolled structure on final mechanical properties after continuous annealing was also investigated.

scholarly journals Controlling the Content and Morphology of Phase Constituents in Nanobainitic Steel Containing 0.6%C to Obtain the Required Ratio of Strength to Plasticity

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 658
Author(s):  
Jarosław Marcisz ◽  
Bogdan Garbarz ◽  
Aleksandra Janik ◽  
Władysław Zalecki
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Total Elongation ◽  
Isothermal Transformation ◽  
Effect Of Temperature ◽  
Isothermal Heat Treatment ◽  
Dilatometric Studies ◽  
Kinetics Of

The phase composition of nanobainitic steel 0.56–0.60%C, 1.68–1.95%Mn, 1.58–1.80%Si, 1.30–1.47%Cr, 0.57–0.75%Mo is described in this paper. The phase composition is controlled in order to obtain diversified mechanical properties for specific applications, such as armor plates. The effect of temperature and time of isothermal heat treatment on both the microstructure and the mechanical properties of the steel were determined. Dilatometric studies, as well as measurements of volume fraction and size distribution of retained austenite were carried out. Analysis of the kinetics of isothermal transformation in the temperature range of 200–225 °C for times of up to 144 h were also carried out, and the parameters of the production process of the steel were determined. A microstructure consisting of nanolathy carbideless bainite and blocky and lathy retained austenite, providing tensile strength of at least 2000 MPa, yield strength of at least 1300 MPa, and total elongation of at least 10% has been found.

Experimental Validation of the Carbon Diffusion Model for Transformation of Ferritic-Pearlitic Microstructure into Austenite during Continuous Annealing of Dual Phase Steels

2013 ◽  
Vol 762 ◽  
pp. 699-704 ◽  
Author(s):  
Monika Pernach ◽  
Krzysztof Bzowski ◽  
Roman Kuziak ◽  
Maciej Pietrzyk
Keyword(s):  
Moving Boundary ◽  
Volume Fraction ◽  
Numerical Models ◽  
Carbon Diffusion ◽  
Avrami Equation ◽  
Continuous Annealing ◽  
The Finite Element Method ◽  
Austenitic Phase ◽  
Austenitic Transformation ◽  
Kinetics Of

Modeling of the transformation of the starting ferritic-pearlitic microstructure into austenite during heating in continuous annealing process was the objective of the work. Kinetics of this transformation was predicted by solving Avrami equation as well as carbon diffusion equation with a moving boundary. Mathematical and numerical models describing austenitic phase transformation were created for the 1D and 2D domains. Developed models were solved using the Finite Difference, as well as the Finite Element Method. Results of the numerical simulations include austenite volume fraction and carbon segregation profiles in the austenite. The former were compared with the experimental data obtained in laboratory simulations of the continuous annealing. Developed and validated model was applied to simulation of the austenitic transformation during annealing of DP steels.

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