scholarly journals Austenite Grain Growth Kinetics after Isothermal Deformation in Microalloyed Steels with Varying Nb Concentrations

2018 ◽  
Vol 58 (2) ◽  
pp. 333-339 ◽  
Author(s):  
Kofi Ahomkah Annan ◽  
Charles Witness Siyasiya ◽  
Waldo Edmund Stumpf
Keyword(s):  
Grain Growth ◽  
Growth Kinetics ◽  
Microalloyed Steels ◽  
Austenite Grain ◽  
Isothermal Deformation ◽  
Grain Growth Kinetics ◽  
Austenite Grain Growth

Nonisothermal Austenite Grain Growth Kinetics in a Microalloyed X80 Linepipe Steel

2010 ◽  
Vol 41 (12) ◽  
pp. 3161-3172 ◽  
Author(s):  
Kumkum Banerjee ◽  
Matthias Militzer ◽  
Michel Perez ◽  
Xiang Wang
Keyword(s):  
Grain Growth ◽  
Growth Kinetics ◽  
Austenite Grain ◽  
Grain Growth Kinetics ◽  
Austenite Grain Growth ◽  
Linepipe Steel

Non-Isothermal Austenite Grain Growth Kinetics in the HAZ of a Microalloyed X-80 Linepipe Steel

2011 ◽  
Vol 172-174 ◽  
pp. 809-814 ◽  
Author(s):  
Kumkum Banerjee ◽  
Michel Perez ◽  
Matthias Militzer
Keyword(s):  
Grain Size ◽  
Heating Rate ◽  
Grain Growth ◽  
Growth Kinetics ◽  
Electron Microscopic ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Grain Growth Kinetics ◽  
Austenite Grain Growth ◽  
Linepipe Steel

Non-isothermal austenite grain growth kinetics under the influence of several combinations of Nb, Ti and Mo containing complex precipitates has been studied in a microalloyed linepipe steel. The goal of these studies is the development of a grain growth model to predict the austenite grain size in the weld heat affected zone (HAZ). A detailed electron microscopic investigations of the as-received steel proved the presence of Ti-rich, Nb-rich and Mo-rich precipitates. Inter and intragranular precipitates of ~5-150 nm have been observed. The steel has been subjected to austenitizing heat treatments to selected peak temperatures of 950, 1150 and 1350°C at various heating rates of 10, 100 and 1000°C/s. Thermal cycles have been found to have a strong effect on the final austenite grain size. The increase in heating rate from 100 to 1000°C/s has a negligible difference in the austenite grain size irrespective of the austenitizing temperature. However, the increase in grain size has been noticed at 10°C/s heating rate for all the austenitizing temperatures. The austenite grain growth kinetics have been explained taking into account the austenite growth in the presence of precipitates.

Austenite Grain Growth Kinetics in a Low C-Mn Steel and a Ti-Nb-V Microalloyed Steel

2014 ◽  
Vol 1019 ◽  
pp. 327-332 ◽  
Author(s):  
K.A. Annan ◽  
C.W. Siyasiya ◽  
W.E. Stumpf ◽  
K.M. Banks ◽  
A.S. Tuling
Keyword(s):  
Grain Growth ◽  
Microalloyed Steel ◽  
Microalloyed Steels ◽  
Growth Equation ◽  
Austenite Grain ◽  
Grain Growth Kinetics ◽  
Increasing Temperature ◽  
Austenite Grain Growth ◽  
Mn Steel ◽  
Good Agreement

The effect of thermal processing (TMP) parameters on grain growth in a low C - Mn steel and a C - Mn steel microalloyed with Nb, Ti and V were compared as part of a wider study on grain growth in microalloyed steels. The grain growth rate was found to be low at low temperatures and short soaking times but increases significantly with both increasing temperature and time. The activation energy Q, the grain growth equation constants n and A were found to be higher in the microalloyed steel than the plain C-Mn steel. A constitutive model for predicting austenite grain growth in the low C-Mn steel and the microalloyed steel has been developed. The predictive potential of the model is in good agreement with the experimental data.

Austenite Grain Growth Kinetics during Continuous Heating of a Microalloyed X-80 Linepipe Steel

2012 ◽  
Vol 715-716 ◽  
pp. 292-296
Author(s):  
Kumkum Banerjee ◽  
Michel Perez ◽  
Matthias Militzer
Keyword(s):  
Grain Size ◽  
Heating Rate ◽  
Grain Growth ◽  
Growth Kinetics ◽  
Continuous Heating ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Grain Growth Kinetics ◽  
Austenite Grain Growth ◽  
Linepipe Steel

Non-isothermal austenite grain growth kinetics has been studied in a microalloyed linepipe steel with complex precipitates containing Ti, Nb and/or Mo. The goal of these experimental studies is to provide the basis for the development of a grain growth model to predict the austenite grain size evolution in the weld heat affected zone (HAZ). Detailed electron microscopic investigations of the as received steel proved the presence of Ti-rich, Nb-rich and Mo-rich precipitates. The steel was subjected to austenitizing heat treatments to selected peak temperatures of 950, 1150 and 1350 °C at heating rates of 10, 100 and 1000 °C/s, respectively. Thermal cycles have been found to have a strong effect on the austenite grain size. Austenite grain sizes increase with peak temperature and decreasing heating rate. However, the increase in heating rate from 100 to 1000 °C/s has a negligible effect on the austenite grain size. The observed austenite grain growth kinetics can be explained taking into account the potential dissolution of Nb-rich precipitates.

scholarly journals Discussion on the Rate Controlling Process of Coarsening of Niobium Carbonitrides in a Niobium Microalloyed Steel

2005 ◽  
Vol 500-501 ◽  
pp. 703-710 ◽  
Author(s):  
David San Martín ◽  
Francisca García Caballero ◽  
Carlos Capdevila ◽  
Carlos García de Andrés
Keyword(s):  
Grain Growth ◽  
Volume Diffusion ◽  
Microalloyed Steels ◽  
Second Phase ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
The Matrix ◽  
Niobium Microalloyed Steel ◽  
Grain Growth Kinetics ◽  
Austenite Grain Growth

Austenite grain growth in microalloyed steels is governed by the coarsening of fine precipitates present at grain boundaries below the grain coarsening temperature. Zener model is widely used in metals to describe the pinning effect of second phase particles precipitated in the matrix. In this work it has been discussed whether grain boundary or volume diffusion is the rate controlling process for the coarsening of the niobium carbonitrides. Calculations on austenite grain growth kinetics, obtained coupling Zener theory and both rate controlling processes of precipitate coarsening, have been compared against experimental austenite grain size results under nonisothermal heating conditions. In this sense, it has been concluded that the coarsening of niobium carbonitrides is mainly controlled by volume diffusion of Nb in austenite.

Austenite grain growth kinetics in Al-killed plain carbon steels

1996 ◽  
Vol 27 (11) ◽  
pp. 3399-3409 ◽  
Author(s):  
Matthias Militzer ◽  
E. Bruce Hawbolt ◽  
T. Ray Meadowcroft ◽  
Alan Giumelli
Keyword(s):  
Grain Growth ◽  
Growth Kinetics ◽  
Carbon Steels ◽  
Austenite Grain ◽  
Grain Growth Kinetics ◽  
Austenite Grain Growth
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