Mathematical Modeling of Microstructure Evolution of V Steels during Hot Rolling of Seamless Tubes

2010 ◽  
Vol 638-642 ◽  
pp. 2537-2542
Author(s):  
Ricardo Nolasco Carvalho ◽  
Marcelo A.C. Ferreira ◽  
Dagoberto Brandão Santos ◽  
Ronaldo Barbosa
Keyword(s):  
Mathematical Modeling ◽  
Microstructure Evolution ◽  
Hot Rolling ◽  
Rolling Mill ◽  
Transfer Time ◽  
Tube Rolling ◽  
Rolling Industry ◽  
Size Evolution ◽  
The Mathematical Model ◽  
Kinetics Of

Torsion and compression testing have been used to simulate microstructure evolution of industry processes. Additionally, mathematical modeling of the industry hot rolling processes has been carried out by several researchers. These models employed equations published in the literature describing kinetics of softening, grain size evolution and grain growth. Validation of the models was carried, in some cases, by comparing the microstructure or the average stress per pass, the latter as calculated from industry rolling mill loads. In the present work, torsion simulation and industry trial results were used to validate the mathematical model presented. Equations used in the model were mostly taken from literature and appropriate modifications were implemented concerning basically two points: a) the transfer time between CMM and SRM, a step in the production line typical for seamless rolling and rather unusual for other industry rolling processes and b) the chemical composition used in tube rolling industry where C equivalent values are usually higher than those used in the rolling of flats.

Modelling Static and Dynamic Kinetics of Microstructure Evolution in Type 316 Stainless Steel During Hot Rolling

2014 ◽  
Author(s):  
Eduardo E. V. Dupin ◽  
Akira Yanagida ◽  
Jun Yanagimoto
Keyword(s):  
Stainless Steel ◽  
Microstructure Evolution ◽  
Hot Rolling ◽  
Compression Tests ◽  
Flow Curves ◽  
Thermomechanical Process ◽  
Double Compression ◽  
Size Evolution ◽  
New Material ◽  
Kinetics Of

In this study, the kinetics of microstructure evolution during hot rolling of type 316 austenitic stainless steel is investigated. First, its kinetics during the dynamic and static events, known as the material genome, is driven by single- and double-compression tests at several temperatures and strain rates. Inverse analysis is used to obtain the flow curves and regression analysis is applied on the coefficients of these flow curves in order to obtain the parameters of the constitutive equations. This new material genome is then used as the boundary condition on an incremental type formulation, taking the dislocation density as the representative variable, to estimate the flow stress and microstructural evolution after the transient changes during rolling schedules of seamless pipes. Actual rolling schedules are simulated and the microstructural changes are compared to industrial data. The outcome of the grain size evolution was reproduced reasonably well showing that proposed methodology can be used to simulate a complex thermomechanical process akin to the rolling schedules of seamless pipes.

Study of the Effect of the Rolling Mill Inter-Stand Tension on the Strip Gauge Deviation

2015 ◽  
Vol 756 ◽  
pp. 414-419 ◽  
Author(s):  
Andrew Alexandrovich Radionov ◽  
Igor Yuryevich Andryushin ◽  
Alexander Sergeevich Karandaev ◽  
Vadim Rifhatovich Khramshin ◽  
Rifhat Ramazanovich Khramshin
Keyword(s):  
Hot Rolling ◽  
Rolling Mill ◽  
Functional Dependencies ◽  
Iron And Steel ◽  
Wide Strip ◽  
Hot Rolling Mill ◽  
Speed Mode ◽  
Technical Solutions ◽  
Iron And Steel Works ◽  
The Mathematical Model

The paper studies issues of the cross impact of tension and strip gauge at the rolling in the continuous roughing sub-train of the wide strip hot-rolling mill. Functional dependencies and chart of the mathematical model defining interrelation between the specific tension and strip gauge increment are provided. Based on the example of the 2,000 mm hot rolling mill of OJSC Magnitogorsk Iron and Steel Works (OAO MMK), it has been proved that rolling is carried out with tension values which exceed several times allowable values. The paper also considers new technical solutions enhancing the speed mode control algorithms and systems of the electric drives of the wide strip hot-rolling mill continuous subgroup.

Investigation of irradiation-induced nucleation processes in silicon and germanium

1995 ◽  
Vol 53 ◽  
pp. 224-225
Author(s):  
Harry A. Atwater ◽  
C.M. Yang ◽  
K.V. Shcheglov
Keyword(s):  
Room Temperature ◽  
Crystal Size ◽  
Initial Distribution ◽  
Engineering Control ◽  
Size Evolution ◽  
Silicon And Germanium ◽  
Ge Quantum Dot ◽  
And Control ◽  
Germanium Quantum Dots ◽  
Kinetics Of

Studies of the initial stages of nucleation of silicon and germanium have yielded insights that point the way to achievement of engineering control over crystal size evolution at the nanometer scale. In addition to their importance in understanding fundamental issues in nucleation, these studies are relevant to efforts to (i) control the size distributions of silicon and germanium “quantum dots𠇍, which will in turn enable control of the optical properties of these materials, (ii) and control the kinetics of crystallization of amorphous silicon and germanium films on amorphous insulating substrates so as to, e.g., produce crystalline grains of essentially arbitrary size.Ge quantum dot nanocrystals with average sizes between 2 nm and 9 nm were formed by room temperature ion implantation into SiO2, followed by precipitation during thermal anneals at temperatures between 30°C and 1200°C[1]. Surprisingly, it was found that Ge nanocrystal nucleation occurs at room temperature as shown in Fig. 1, and that subsequent microstructural evolution occurred via coarsening of the initial distribution.

Analysis of interconnections between technical systems on hierarchically connected technological levels of steel sheet production by hot rolling

2020 ◽  
Vol 76 (8) ◽  
pp. 847-855
Author(s):  
E. N. Shiryaeva ◽  
M. A. Polyakov ◽  
D. V. Terent'ev
Keyword(s):  
Hot Rolling ◽  
Systems Analysis ◽  
Rolling Mill ◽  
Steel Sheet ◽  
Technological System ◽  
Necessary Condition ◽  
Rolled Sheet ◽  
Technological Systems ◽  
Hot Rolling Mill ◽  
Technical Systems

Complexity of modern metallurgical plants, presence of great number of horizontal and vertical interactions between their various structural subdivisions makes it necessary to apply a systems analysis to elaborate effective measures for stable development of a plant operation. Among such measures, digitalization of a plant is widespread at present. To implement the digitalization it is necessary to have clear vision about links at all the levels of the technological system of a plant. A terminology quoted, accepted in the existing regulatory documents for defining of conceptions, comprising the technological system. It was shown, that the following four hierarchical levels of technological systems are distinguished: technological systems of operations, technological systems of processes, technological systems of production subdivisions and technological systems of plants. A hierarchical scheme of technological systems of hot-rolled sheet production at an integrated steel plant presented. Existing horizontal and vertical links between the basic plant’s shops shown. Peculiarities of flows of material, energy and information at the operation “rolling” of the technological system “hot rolling of a steel sheet” considered. As a technical system of the technological process of the hot rolling, the hot rolling mill was chosen. A structural diagram of the hot rolling mill was elaborated, the mill being consisted of reheating furnaces, roughing and finishing stand groups, with an intermediate roll-table between them, and down-coilers section. Since the rolling stands are the basic structural elements of the hot rolling mill, structural diagrams of a roughing and a finishing stands were elaborated. Results of the systems analysis of the technological and technical systems, hierarchically linked in the process of steel sheet hot rolling, can be applied for perfection of organization structure of the whole plant, as well as for elaboration mathematical models of a system separate elements functioning, which is a necessary condition for a plant digitalization.

scholarly journals Conceptual and Mathematical Modeling of a Coastal Aquifer in Eastern Delta of R. Nestos (N. Greece)

Hydrology ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 23
Author(s):  
Ioannis Gkiougkis ◽  
Christos Pouliaris ◽  
Fotios-Konstantinos Pliakas ◽  
Ioannis Diamantis ◽  
Andreas Kallioras
Keyword(s):  
Mathematical Modeling ◽  
Groundwater Flow ◽  
Coastal Aquifer ◽  
Flow Model ◽  
Meteorological Data ◽  
Field Measurements ◽  
Groundwater Flow Model ◽  
Aquifer System ◽  
Geophysical Surveys ◽  
The Mathematical Model

In this paper, the development of the conceptual and groundwater flow model for the coastal aquifer system of the alluvial plain of River Nestos (N. Greece), that suffers from seawater intrusion due to over-pumping for irrigation, is analyzed. The study area is a typical semi-arid hydrogeologic environment, composed of a multi-layer granular aquifers that covers the eastern coastal delta system of R. Nestos. This study demonstrates the results of a series of field measurements (such as geophysical surveys, hydrochemical and isotopical measurements, hydro-meteorological data, land use, irrigation schemes) that were conducted during the period 2009 to 2014. The synthesis of the above resulted in the development of the conceptual model for this aquifer system, that formed the basis for the application of the mathematical model for simulating groundwater flow. The mathematical modeling was achieved using the finite difference method after the application of the USGS code MODFLOW-2005.

scholarly journals Experimental and Numerical Study of the Effects of the Reversal Hot Rolling Conditions on the Recrystallization Behavior of Austenite Model Alloys

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 26
Author(s):  
Krzysztof Muszka ◽  
Mateusz Sitko ◽  
Paulina Lisiecka-Graca ◽  
Thomas Simm ◽  
Eric Palmiere ◽  
...  
Keyword(s):  
Microstructure Evolution ◽  
Hot Rolling ◽  
Strain Path ◽  
Physical Simulation ◽  
Numerical Study ◽  
Kinematic Hardening ◽  
Process Window ◽  
Recrystallization Behavior ◽  
Full Field ◽  
Strain Reversal

The experimental and numerical study of the effects of the recrystallization behavior of austenite model alloys during hot plate rolling on reverse rolling is the main goal of the paper. The computer models that are currently applied for simulation of reverse rolling are not strain-path-sensitive, thus leading to overestimation of the processing parameters outside the accepted process window (e.g., deformation in the partial austenite recrystallization region). Therefore, in this work, a particular focus is put on the investigation of strain path effects that occur during hot rolling and their influence on the microstructure evolution and mechanical properties of microalloyed austenite. Both experimental and numerical techniques are employed in this study, taking advantage of the integrated computational material engineering concept. The combined isotropic–kinematic hardening model is used for the macroscale predictions to take into account softening effects due to strain reversal. The macroscale model is additionally enriched with the full-field microstructure evolution model within the cellular automata framework. Examples of obtained results, highlighting the role of the strain reversal on the microstructural response, are presented within the paper. The combination of the physical simulation of austenitic model alloys and computer modeling provided new insights into optimization of the processing routes of advanced high-strength steels (AHSS).

scholarly journals Vibration Characteristics of Hot Rolling Mill Rolls Based on Elastoplastic Hysteretic Deformation

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 869
Author(s):  
Rongrong Peng ◽  
Xingzhong Zhang ◽  
Peiming Shi
Keyword(s):  
Hot Rolling ◽  
Internal Resonance ◽  
Rolling Mill ◽  
Rolling Force ◽  
Subharmonic Resonance ◽  
Force Model ◽  
Maximum Lyapunov Exponent ◽  
Vibration System ◽  
Hot Rolling Mill ◽  
Rolling Mill Vibration

Based on the analysis of the influence of roll vibration on the elastoplastic deformation state of a workpiece in a rolling process, a dynamic rolling force model with the hysteresis effect is established. Taking the rolling parameters of a 1780 mm hot rolling mill as an example, we analyzed the hysteresis between the dynamic rolling force and the roll vibration displacement by varying the rolling speed, roll radius, entry thickness, front tension, back tension, and strip width. Under the effect of the dynamic rolling force and considering the nonlinear effect between the backup and work rolls as well as the structural constraints on the rolling mill, a hysteretic nonlinear vertical vibration model of a four-high hot rolling mill was established. The amplitude-frequency equations corresponding to 1/2 subharmonic resonance and 1:1 internal resonance of the rolling mill rolls were obtained using a multi-scale approximation method. The amplitude-frequency characteristics of the rolling mill vibration system with different parameters were studied through a numerical simulation. The parametric stiffness and nonlinear stiffness corresponding to the dynamic rolling force were found to have a significant influence on the amplitude of the subharmonic resonance system, the bending degree of the vibration curve, and the size of the resonance region. Moreover, with the change in the parametric stiffness, the internal resonance exhibited an evident jump phenomenon. Finally, the chaotic characteristics of the rolling mill vibration system were studied, and the dynamic behavior of the vibration system was analyzed and verified using a bifurcation diagram, maximum Lyapunov exponent, phase trajectory, and Poincare section. Our research provides a theoretical reference for eliminating and suppressing the chatter in rolling mills subjected to an elastoplastic hysteresis deformation.

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