Mathematical Modeling for the Simultaneous Prediction of Rolling Force and Microstructure Evolution in the Tandem Hot Rolling of Fine Grain Steel Sheets and Plates

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.

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Combined Macro–Micro Modeling for Rolling Force and Microstructure Evolution to Produce Fine Grain Hot Strip in Tandem Hot Strip Rolling

ISIJ International ◽

10.2355/isijinternational.47.1475 ◽

2007 ◽

Vol 47 (10) ◽

pp. 1475-1484 ◽

Cited By ~ 14

Author(s):

Toshiharu Morimoto ◽

Fuyuki Yoshida ◽

Ichiro Chikushi ◽

Jun Yanagimoto

Keyword(s):

Microstructure Evolution ◽

Rolling Force ◽

Hot Strip Rolling ◽

Strip Rolling ◽

Fine Grain ◽

Hot Strip ◽

Micro Modeling

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Investigation of the Microstructural Evolution during Hot Stamping of a Carburized Complex Phase Steel by Laser-Ultrasonics

Materials ◽

10.3390/ma14081836 ◽

2021 ◽

Vol 14 (8) ◽

pp. 1836

Author(s):

Alexander Horn ◽

Marion Merklein

Keyword(s):

Microstructural Evolution ◽

Hot Stamping ◽

Laser Ultrasonics ◽

Complex Phase ◽

Finished Steel ◽

Steel Sheets ◽

Fine Grain ◽

Martensitic Microstructure ◽

Ultrasound Sensor ◽

Hot Stamping Steel

Prior carburization of semi-finished steel sheets is a new process variant in hot stamping to manufacture parts with tailored properties. Compared to conventional hot stamping processes, a complex phase typed steel alloy is used instead of 22MnB5. Yet recent investigations focused on final mechanical properties rather than microstructural mechanisms cause an increase in strength. Thus, the influence of additional carburization on the microstructural evolution during hot stamping of a complex phase steel CP-W®800 is investigated within this work. The phase transformation behavior, as well as the grain growth during austenitization, is evaluated by in-situ measurements employing a laser-ultrasound sensor. The results are correlated with additional hardness measurements in as-quenched condition and supplementary micrographs. The experiments reveal that the carburization process significantly improves the hardenability of the CP-W®800. However, even at quenching rates of 70 K/s no fully martensitic microstructure was achievable. Still, the resulting hardness of the carburized samples might exceed the fully martensitic hardness of 22MnB5 derived from literature. Furthermore, the carburization process has no adverse effect on the fine grain stability of the complex phase steel. This makes it more robust in terms of grain size than the conventional hot stamping steel 22MnB5.

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

Metals ◽

10.3390/met11010026 ◽

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).

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

Metals ◽

10.3390/met11060869 ◽

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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Microstructure evolution of ultra-fine grain low-carbon steel tubular undergoing radial expansion process

Materials Science and Engineering A ◽

10.1016/j.msea.2015.12.016 ◽

2016 ◽

Vol 654 ◽

pp. 94-106 ◽

Cited By ~ 7

Author(s):

Omar S. Al-Abri ◽

Tasneem Pervez ◽

Majid H. Al-Maharbi ◽

Rashid Khan

Keyword(s):

Carbon Steel ◽

Microstructure Evolution ◽

Low Carbon Steel ◽

Radial Expansion ◽

Low Carbon ◽

Expansion Process ◽

Fine Grain

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Microstructure Evolution of a Fine Grain Al-50wt%Si Alloy Fabricated by High Energy Milling

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.479.54 ◽

2011 ◽

Vol 479 ◽

pp. 54-61 ◽

Cited By ~ 2

Author(s):

Fei Wang ◽

Ya Ping Wang

Keyword(s):

Grain Growth ◽

Microstructure Evolution ◽

Room Temperature ◽

Milling Time ◽

High Energy ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Laser Method ◽

X Ray ◽

Fine Grain

Microstructure evolution of high energy milled Al-50wt%Si alloy during heat treatment at different temperature was studied. Scanning electron microscope (SEM) and X-ray diffraction (XRD) results show that the size of the alloy powders decreased with increasing milling time. The observable coarsening of Si particles was not seen below 730°C in the high energy milled alloy, whereas, for the alloy prepared by mixed Al and Si powders, the grain growth occurred at 660°C. The activation energy for the grain growth of Si particles in the high energy milled alloy was determined as about 244 kJ/mol by the differential scanning calorimetry (DSC) data analysis. The size of Si particles in the hot pressed Al-50wt%Si alloy prepared by high energy milled powders was 5-30 m at 700°C, which was significantly reduced compared to that of the original Si powders. Thermal diffusivity of the hot pressed Al-50wt%Si alloy was 55 mm2/s at room temperature which was obtained by laser method.

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