scholarly journals Drying behavior of steel-ladle lining refractory castables under continuous heating rate

2021 ◽  
Author(s):  
T.M. Cunha ◽  
M.H. Moreira ◽  
M.F. Santos ◽  
A.P. Luz ◽  
V.C. Pandolfelli
Keyword(s):  
Heating Rate ◽  
Ladle Lining ◽  
Continuous Heating ◽  
Steel Ladle ◽  
Refractory Castables ◽  
Drying Behavior

Modeling of Non-Isothermal Austenite Formation in Cr5 Roller Steel

2013 ◽  
Vol 712-715 ◽  
pp. 34-37
Author(s):  
Fang Zhang
Keyword(s):  
Activation Energy ◽  
Heating Rate ◽  
Continuous Heating ◽  
Austenite Formation ◽  
Transformation Kinetics ◽  
Isothermal Heating ◽  
Critical Temperatures ◽  
Modified Model ◽  
Logarithmic Relationship ◽  
Good Agreement

A modified model describing the austenite reaction was developed that took into account the effect of heating rate. The model considered the variation of activation energy during non-isothermal heating and one set of model parameter was adequate to predict the formation of austenite. To verify the theoretical model, the process of austenite formation during continuous heating in Cr5 roller steel with pearlite and ferrite mixed initial microstructure was analyzed by dilatation experiment. The results show that a strong logarithmic relationship between apparent activation energy and heating rate. Experimental kinetic transformations as well as critical temperatures of austenite reaction are in good agreement with the calculations. The model can be used to describe the transformation kinetics at an intermediate heating rate.

Effect of Heating Rate and Silicon Content on Kinetics of Austenite Formation during Continuous Heating

2014 ◽  
Vol 783-786 ◽  
pp. 771-776 ◽  
Author(s):  
B. Hernández-Morale ◽  
O. Vázquez-Gómez ◽  
E. López-Martínez ◽  
H.J. Vergara-Hernández ◽  
L. Olmos
Keyword(s):  
Heating Rate ◽  
Silicon Content ◽  
Relative Length ◽  
Protective Atmosphere ◽  
Continuous Heating ◽  
Austenite Formation ◽  
Transformation Kinetics ◽  
Critical Temperatures ◽  
High Silicon ◽  
Kinetics Of

The first step in a heat treating cycle is the austenitizing of the as-received material. Despite its importance, this step has received relatively little attention. In this work, the kinetics of austenite formation during continuous heating tests of steel samples with low and high silicon content was determined as a function of heating rate. The microstructural evolution was characterized through dilatometric analysis of cylindrical samples (7 mm × 20 mm), continuously heated in a protective atmosphere at constant heating rates ranging from 2 to 40 °C/min. The critical temperatures and the transformation kinetics were determined from the derivative of the relative length change as a function of temperature. As the heating rate increases the critical temperatures and the transformation temperature range increase; the addition of silicon produces a more marked effect. The transformation kinetics data were correlated using an Avrami-type equation. The kinetic parameter n is nearly independent of heating rate while the parameter k is a strong function of the heating rate; in both cases, slightly larger values were obtained for the high-silicon steel.

scholarly journals Drying behavior of dense refractory castables. Part 2 – Drying agents and design of heating schedules

2021 ◽  
Author(s):  
A.P. Luz ◽  
M.H. Moreira ◽  
R. Salomão ◽  
M.A.L. Braulio ◽  
V.C. Pandolfelli
Keyword(s):  
Refractory Castables ◽  
Drying Behavior ◽  
Dense Refractory

Kinetics Study on Non-Isothermal Crystallization of Amorphous Alloy Mg65Cu15Ag10Y10

2011 ◽  
Vol 413 ◽  
pp. 432-438
Author(s):  
Xiao Jun Wang ◽  
Tian Dong Xia ◽  
Xue Ding Chen
Keyword(s):  
Activation Energy ◽  
Amorphous Alloy ◽  
Heating Rate ◽  
Volume Fraction ◽  
Strong Dependence ◽  
Continuous Heating ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Local Activation ◽  
Local Activation Energy

The crystallization kinetics of amorphous alloy Mg65Cu15Ag10Y10has been studied by differential scanning calorimetry in the mode of continuous heating annealing. It is found that both DSC curves and activation energy show a strong dependence on the heating rate. The activation energy for crystallization are determined as 186.1 and 184.4 KJ mol−1for the heating rates β=5-20 Kmin−1, and 107.5 and 110.0 KJmol−1for the heating rates β=20-80Kmin−1, when using the Kissinger equation and the Ozawa equation, respectively. Local activation energy at any volume fraction crystallized was obtained by the general Ozawa's isoconversional method. The average value of local activation energy for heating rates ranging from 5 to 20Kmin−1is 180.9 KJ mol−1and for heating rates ranging between 20 and 80Kmin−1is 110.2 KJ mol−1. Using the Suriñach curve fitting procedure, the kinetics mode was specified. The JMA kinetics is manifested as a rule in the early stages of the crystallization. The JMA exponent,n, initially being larger than 4 and continuously decreases to about 2 along with the development of crystallization. The NGG-like mode dominates in the advanced stages of the transformation. These two modes are mutually independent. The proportion between the JMA-like and the NGG-like modes is related to the heating rate.

Modelling the ferrite/carbide → austenite transformation of hypoeutectoid and hypereutectoid steels

2004 ◽  
Vol 120 ◽  
pp. 111-119
Author(s):  
H. Surm ◽  
O. Kessler ◽  
M. Hunkel ◽  
F. Hoffmann ◽  
P. Mayr
Keyword(s):  
Heat Treatment ◽  
Computer Simulation ◽  
Heating Rate ◽  
Collaborative Research ◽  
Avrami Equation ◽  
Continuous Heating ◽  
Constant Heating Rate ◽  
Austenite Transformation ◽  
Hypereutectoid Steels ◽  
Constant Heating

In the project “Distortion compatible heating during heat treatment’’ of the Collaborative Research Center 570 “Distortion Engineering’’ the mechanisms of distortion development during heating are analyzed. The factors of the austenitizing process influencing distortion during heat treatment are investigated by experiments as well as by computer simulation. To predict distortion during heating with computer simulation, the ferrite + carbide into austenite transformation has to be modeled accurately. A model, based on the Johnson-Mehl-Avrami equation, was developed to describe the transformation of hypoeutectoid and hypereutectoid steels during continuous heating with constant heating rate.

Key features of alumina/magnesia/graphite refractories for steel ladle lining

2000 ◽  
Vol 20 (9) ◽  
pp. 1419-1427 ◽  
Author(s):  
W.S Resende ◽  
R.M Stoll ◽  
S.M Justus ◽  
R.M Andrade ◽  
E Longo ◽  
...  
Keyword(s):  
Ladle Lining ◽  
Steel Ladle ◽  
Key Features

scholarly journals Kinetics of Austenite Grain Growth during a Continuous Heating of a Niobium Microalloyed Steel

2004 ◽  
Vol 467-470 ◽  
pp. 929-934 ◽  
Author(s):  
David San Martín ◽  
Francisca García Caballero ◽  
Carlos Capdevila ◽  
C. Carcía de Andrés
Keyword(s):  
Grain Size ◽  
Grain Boundaries ◽  
Heating Rate ◽  
Grain Growth ◽  
Continuous Heating ◽  
Second Phase ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Average Grain Size ◽  
The Matrix

Grain growth is a thermally activated process in which the average grain size increases as temperature and time increases. The driving force for grain growth results from the decrease in the free energy associated with the reduction in total grain boundary energy. There are several known factors that influence the migration of grain boundaries such as second phase particles precipitated in the matrix and the solute elements segregated at grain boundaries. The austenite grain boundaries are revealed using the thermal etching method. Carbon extraction replicas were prepared to determine the composition and size of precipitates present in the matrix. In this work, the evolution of the average prior austenite grain size (PAGS) of a low carbon steel microalloyed with niobium is studied as a function of temperature and heating rate. Austenite grains show a two-stage growth. It has been found that as heating rate increases, the grain coarsening temperature (TGC) increases and the grain size at that temperature decreases. TGC temperature lies around 40-60°C below the temperature for complete dissolution of carbonitrides (TDISS).

scholarly journals A Method for Steel Ladle Lining Optimization Applying Thermomechanical Modeling and Taguchi Approaches

JOM ◽  
2018 ◽  
Vol 70 (11) ◽  
pp. 2449-2456 ◽  
Author(s):  
Aidong Hou ◽  
Shengli Jin ◽  
Harald Harmuth ◽  
Dietmar Gruber
Keyword(s):  
Ladle Lining ◽  
Steel Ladle ◽  
Thermomechanical Modeling

scholarly journals Determination of the critical points in solid-state phase transformation of some hypoeutectoid steels

2019 ◽  
Vol 95 ◽  
pp. 04004
Author(s):  
Constantin Dulucheanu ◽  
Traian Lucian Severin ◽  
Alexandru Potorac ◽  
Luminita Irimescu
Keyword(s):  
Phase Transformation ◽  
Solid State ◽  
Heating Rate ◽  
Critical Points ◽  
Continuous Heating ◽  
Eutectoid Transformation ◽  
Finish Temperature ◽  
Solid State Phase Transformation ◽  
Start Temperature

This study allowed, by dilatometric analyses, both to highlight the solid state transformations that occurred during the continuous heating of two hypoeutectoid steels, as well as to investigate the effect of the heating rate on the critical points at which these transformations occurred. The eutectoid transformation (the pearlite dissolution into austenite) was carried out in a temperatures interval, ranging between pearlite dissolution start temperature (Ac1) and pearlite dissolution finish temperature (denoted Acfp in this article). Increasing the heating rate determined a displacement of the critical points in solid-state phase transformation to higher temperatures; these displacements were more significant for the Acfp point, than for the critical points Ac1 and Ac3.

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