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    Prediction of flow behavior during warm working

    , Article ISIJ International ; Volume 44, Issue 11 , 2004 , Pages 1867-1873 ; 09151559 (ISSN) Serajzadeh, S ; Sharif University of Technology
    Iron and Steel Institute of Japan  2004
    Abstract
    In this work, the effects of dynamic strain aging and dynamic recovery on metal flow during warm working are studied. Compression experiments are utilized to assess the flow behavior of a low carbon steel under warm deformation conditions. Then, a two dimensional finite element routine is coupled with dynamic recovery and dynamic strain aging models. In this way, the temperature and the velocity fields are predicted during warm working operations with regard to the effects of dynamic recovery and dynamic strain aging. Warm rolling tests are performed in order to verify the modelling results. Comparison between the predicted and measured roll forces shows reliability of the employed model  

    A study on strain ageing during and after warm rolling of a carbon steel

    , Article Materials Letters ; Volume 62, Issue 6-7 , 2008 , Pages 946-948 ; 0167577X (ISSN) Serajzadeh, S ; Akhgar, J. M ; Sharif University of Technology
    2008
    Abstract
    In this study, strain ageing during and after warm rolling of a carbon steel has been investigated. At the first step, the occurrence of serrated flow was studied by means of tensile tests at different temperatures and strain rates. In the next stage, warm rolling experiments were performed under different rolling conditions and then the samples were aged at the room temperature for a period of 3 months. For both aged and non-aged samples, tensile tests were employed to evaluate their mechanical properties. The results show that static strain ageing is possible to happen in the utilized ageing period and increases the yield stress of the aged steel. However, the samples that experience both... 

    Modelling the warm rolling of a low carbon steel

    , Article Materials Science and Engineering A ; Volume 371, Issue 1-2 , 2004 , Pages 318-323 ; 09215093 (ISSN) Serajzadeh, S ; Sharif University of Technology
    2004
    Abstract
    Dynamic strain ageing may occur during warm working of low carbon steels and causes significant changes in flow behaviour and microstructure of the deformed material. Therefore, for a proper designing of an industrial forming process performing under warm deformation conditions, the effect of dynamic strain aging should be taken into account. The aim of this investigation is to predict the velocity and the temperature fields within the rolling metal with regard to the dynamic strain aging. For this purpose, compression tests at various temperatures and strain rates have been conducted to evaluate dynamic strain aging in a low carbon steel. Then, by coupling the experimental results with a... 

    Effects of deformation parameters on the final microstructure and mechanical properties in warm rolling of a low-carbon steel

    , Article International Journal of Advanced Manufacturing Technology ; Volume 34, Issue 3-4 , 2007 , Pages 262-269 ; 02683768 (ISSN) Serajzadeh, S ; Mohammadzadeh, M ; Sharif University of Technology
    2007
    Abstract
    The effects of warm rolling parameters on the final microstructure and mechanical properties of a low-carbon steel were investigated. In doing so, the steel strips were pre-heated at various temperatures and rolled at different reductions and rolling speeds. Then, microstructural studies were performed and, also, the mechanical properties of the rolled samples were measured by tensile and hardness testing. An optimum rolling program was determined with the aids of experimental results and a mathematical model based on the finite element method (FEM) developed for the warm rolling conditions. The results show that, at high temperatures and low rolling speeds, the roll forces are reduced;... 

    Theoretical and Experimental Investigation of Warm Rolling of Al Alloy 2017

    , M.Sc. Thesis Sharif University of Technology Khalili, Leila (Author) ; Serajzadeh, Siamak (Supervisor)
    Abstract
    A mathematical model was developed to assess thermomechanical behavior of work rolls during warm rolling processes of AA2017. A combined finite element analysis-slab method was first developed to determine thermal and mechanical responses of the strip being rolled under steady-state conditions; Then, the calculated roll pressure and temperature field were utilized as the governing boundary conditions for the thermomechanical problem of the work roll. Finally, the thermomechanical stresses within the work rolls were predicted by a thermoelastic finite element approach. The results indicate that, in warm strip rolling, thermal and mechanical stresses developed in the work rolls are comparable.... 

    Investigation of the Effect of Warm Rolling on Microstructure and Mechanical Properties of Severely Deformed Aluminum Sheets

    , M.Sc. Thesis Sharif University of Technology Charkhesht, Vahid (Author) ; Kazeminezhad, Mohsen (Supervisor)
    Abstract
    Lots of researches have been carried out on the severe plastic deformation (SPD) and annealing of the aluminum up to now. Due to the different annealing behavior of the severely deformed metals and on the other hand the necessity to the rollig for producing the thin SPD sheets, so the purpose of the recent study is producing the thinned sheets with applying the temperature simultaneously. Dislocations density increases by SPD so it confines their movement and cause to the higher strength of the material. Rolling of the SPDed sheets increase the mechanical properties. Grain boundary energy increases with this mechanical improvement and results in lower ductility. So, it is necessary to... 

    A study on Warm Rolling Behavior of an Austenitic Stainless Steel and the Mechanical Properties of the Rolled Product

    , M.Sc. Thesis Sharif University of Technology Ghadamgahi, Mojtaba (Author) ; Serajzade, Siamak (Supervisor)
    Abstract
    In this study, thermo-mechanical behavior of an austenitic stainless steel AISI316L was investigated using mathematical modeling and experimental analysis during warm rolling process. First, the thermo-mechanical analysis was carried out employing the finite element software, Abaqus CAE, to assess temperature, strain, velocity and stress distribution during rolling. Then, rolling operations on 316L austenitic steel were performed under different working conditions while mechanical testing as well as microstructural observations were made on the rolled steels. Using simulation results and practical data, microstructural events and mechanical properties after warm rolling of stainless steel... 

    Prediction of Temperature and Strain Distribution in the Warm Rolling of Austenite Stainless Steel

    , M.Sc. Thesis Sharif University of Technology Nemati, Elham (Author) ; Serajzadeh, Siamak (Supervisor)
    Abstract
    In this research, the hot and warm rolling of stainless steel 304 was studied. First the rolling process was simulated using Finite Element Method software ABAQUS and the distribution of temperature and strain in the process under discontinuous conditions were predicted. Next, hot and warm rolling of stainless steel 304 under different conditions was carried out. Specimens were cut and subject to mechanical testing, metallography and electron microscopic studies. Data obtained from these experiments and the predicted trends from ABAQUS were compared, therefore studying the effect of different parameters on the microstructure and mechanical properties of the rolled specimen. Results indicate... 

    The Effect of Warm Rolling on Severely Deformed Copper

    , M.Sc. Thesis Sharif University of Technology Nemati, Masoud (Author) ; Kazeminezhad, Mohsen (Supervisor)
    Abstract
    Since the increase in the strength of metals resulting from the severe plastic deformation (SPD) leads to a reduction in their ductility, recently, several studies have been carried out on the deformation of metals. One if the goals has been increasing the ductility while maintaining the strength. In this project, copper is undergone severe plastic deformation in a constrained groove pressing (CGP) process. According to previous studies, it has been determined that with an optimal annealing process, not only the strength is not decreased, but also it is slightly increased and also the ductility is enhanced. Thus, in order to improve the surface of copper after CGP and also optimize its... 

    On the influence of deformation rate and cooling media on the static strain aging of a warm-rolled low carbon steel

    , Article International Journal of Material Forming ; Volume 6, Issue 3 , February , 2013 , Pages 417-422 ; 19606206 (ISSN) Koohbor, B ; Ohadi, D ; Sharif University of Technology
    2013
    Abstract
    An investigation was performed on the static strain aging behavior of warm-rolled low carbon steel during a nearly 1-year aging period, from the view point concerning with influence of changing the deformation speed and cooling media. Mechanical response of the examined material during aging period was evaluated through variations occurred in strength and hardness of the warm-deformed steel. It was shown that changing the rolling speed as well as cooling rate, may result in the occurrence of different metallurgical phenomena, consequently altering the aging kinetics of the material. It was also found that by increasing rolling speed, an increase in the value of hardness and UTS takes place,... 

    Theoretical and Experimental Investigations of Deformation Behavior from Stainless Steel 304L During Rolling at Evelated Temperatures

    , M.Sc. Thesis Sharif University of Technology Pourabdollah, Pegah (Author) ; Serajzadeh, Siamak (Supervisor)

    Thermomechanical behavior of work rolls during warm strip rolling

    , Article Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science ; 2012 , Pages 1-11 ; 10735615 (ISSN) Khalili, L ; Serajzadeh, S ; Koohbor, B ; Sharif University of Technology
    Abstract
    A mathematical model was developed to assess thermomechanical behavior of work rolls during warm rolling processes. A combined finite element analysis-slab method was first developed to determine thermal and mechanical responses of the strip being rolled under steady-state conditions, and then, the calculated roll pressure and temperature field were utilized as the governing boundary conditions for the thermomechanical problem of the work roll. Finally, the thermomechanical stresses within the work rolls were predicted by a thermoelastic finite element approach. The results of the model indicate that, in warm strip rolling, thermal and mechanical stresses developed in the work rolls are... 

    Effect of rolling speed on the occurrence of strain aging during and after warm rolling of a low-carbon steel

    , Article Journal of Materials Science ; Volume 45, Issue 13 , July , 2010 , Pages 3405-3412 ; 00222461 (ISSN) Koohbor, B ; Ohadi, D ; Serajzadeh, S ; Akhgar, J. M ; Sharif University of Technology
    2010
    Abstract
    In this study, effect of rolling speed on strain aging phenomena in warm rolling of a carbon steel has been investigated. For this purpose, by using a mathematical model and predicting temperature and strain rate fields, the possibility of occurrence of dynamic strain aging during the warm rolling was first evaluated. In the next stage, warm-rolled samples were aged up to 11 months at room temperature for studying the kinetics of static strain aging, while mechanical tests as well as microstructural evolutions have been performed to determine the effect of strain aging on material behavior. The results indicate that dynamic strain aging may not occur for the employed rolling program;... 

    Finite element modeling of thermal and mechanical stresses in work-rolls of warm strip rolling process

    , Article Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture ; Volume 230, Issue 6 , 2016 , Pages 1076-1086 ; 09544054 (ISSN) Koohbor, B ; Sharif University of Technology
    SAGE Publications Ltd 
    Abstract
    An integrated mathematical model was developed to study the thermo-mechanical behavior of strips and work-rolls during warm rolling process of steels. A two-dimensional finite element analysis was first employed to solve for the thermo-mechanical response of the rolled strip under steady-state conditions. The calculated roll pressure and temperature fields were then used to apply proper boundary conditions for solving the governing thermo-mechanical problem for the work-roll. The obtained results indicate that in warm strip rolling of steels, the thermal and mechanical stresses developed within the work-roll are comparable; however, the more significant influence is due to heating and... 

    Electron back scattered diffraction (EBSD) characterization of warm rolled and accumulative roll bonding (ARB) processed ferrite

    , Article Journal of Materials Processing Technology ; Volume 209, Issue 3 , 2009 , Pages 1436-1444 ; 09240136 (ISSN) Kolahi, A ; Akbarzadeh, A ; Barnett, M. R ; Sharif University of Technology
    2009
    Abstract
    An interstitial free (IF) steel was severely deformed using accumulative roll bonding (ARB) process and warm rolling. The maximum equivalent strains for ARB and warm rolling were 4.8 and 4.0, respectively. The microstructure and micro-texture were studied using optical microscopy and scanning electron microscopy equipped with electron back scattered diffraction (EBSD). The grain size and misorientation obtained by both methods are in the same range. The microstructure in the ARB samples after 6 cycles is homogeneous, although a grain size gradient is observed at the layers close to the surface. The through thickness texture gradient in the ARB samples is different from the warm rolled... 

    A model for prediction of flow behavior and temperature distribution during warm rolling of a low carbon steel

    , Article Materials and Design ; Volume 27, Issue 7 , 2006 , Pages 529-534 ; 02641275 (ISSN) Serajzadeh, S ; Sharif University of Technology
    2006
    Abstract
    A two-dimensional finite element analysis is coupled with dynamic recovery and dynamic strain aging models to achieve metal flow during warm deformation of a low carbon steel. In order to assess metal behavior, compression experiments are utilized under warm deformation conditions and the results are used in the model and temperature and velocity fields are predicted with regard to the effects of dynamic recovery and dynamic strain aging. In addition, warm rolling tests are performed to verify the modelling results. Comparison between the predicted and measured roll forces shows reliability of the employed model. © 2005 Elsevier Ltd. All rights reserved  

    An investigation into the effect of strain ageing on mechanical properties of low-carbon steels after warm rolling

    , Article International Journal of Advanced Manufacturing Technology ; Volume 40, Issue 7-8 , 2009 , Pages 721-728 ; 02683768 (ISSN) Serajzadeh, S ; Sharif University of Technology
    2009
    Abstract
    In this study, the effect of strain ageing on mechanical properties of warm-rolled steel is investigated. Warm-rolling experiments together with mechanical testing are employed to investigate the effect of processing parameters on the ageing kinetics during and after warm rolling of a low-carbon steel. To do so, the occurrence of dynamic strain ageing is first determined by means of a two-dimensional thermo-mechanical model and then the effect of this phenomenon on the subsequent static strain ageing after warm rolling is studied employing mechanical testing. The results show that the occurrence of dynamic strain ageing during warm rolling may effectively alter the progress of the subsequent...