scholarly journals Development of Software for the Simulation of Rolling Steel Under the Coexistence of Liquid and Solid State / Rozwój Oprogramowania Do Symulacji Walcowania Stali W Warunkach Współistnienia Fazy Ciekłej I Stałej

2015 ◽  
Vol 60 (4) ◽  
pp. 2783-2790
Author(s):  
D. Jędrzejczyk ◽  
M. Hojny ◽  
M. Głowacki
Keyword(s):  
Plastic Deformation ◽  
Continuous Casting ◽  
Mathematical Models ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Casting Process ◽  
Density Variation ◽  
Rolled Strip ◽  
Final Phase ◽  
Three Dimensional Model

The paper presents the results of the application simulating the rolling process of steel in terms of coexistence of liquid and solid phases. The created mathematical models can be the basis for creation of systems that simulate the final phase of the continuous casting process relying on using a roller burnishing machine for continuous casting of steel. For a complete description of the performance of the material during deformation in these conditions, the constructed mathematical model is a fully three-dimensional model and consists of three parts: thermal, mechanical, and density variation submodels. The thermal model allows the prediction of temperature changes during plastic deformation of solidifying material. The mechanical model determines the kinetics of plastic continuum flow in the solid and semi-solid states, and the resulting deformation field. The temperature of the process forces supplementing the description of the performance of the material with a density variation model that allows the prediction of changes in the density of the material during the final phase of solidification with simultaneous plastic deformation. For the purpose built model, experimental studies were performed using a physical simulator Gleeble 3800®. They allowed the determination of the necessary physical properties of the metal within the temperature of change state. In addition to presenting the developed models the work also includes the description of the author’s application that uses the above mathematical models. The application was written in the fully object-oriented language C++ and is based on the finite element method. The developed application beside the module data input, also consist of a module of three-dimensional visualization of the calculations results. Thanks to it, the analysis of the distribution of the particular rolling parameters in any cross-section of the rolled strip will be possible. The paper presents the results of the authors’ research in the area of the advanced computer simulation.

3D Thermo-Mechanical Modelling of Wheel and Belt Continuous Casting

2011 ◽  
Vol 693 ◽  
pp. 235-244 ◽  
Author(s):  
John F. Grandfield ◽  
Sébastien Dablement ◽  
Hallvard Gustav Fjær ◽  
Dag Mortensen ◽  
Michael Lee ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Continuous Casting ◽  
Three Dimensional ◽  
Casting Process ◽  
Liquid Pool ◽  
Air Gap ◽  
Temperature Measurements ◽  
Heat Extraction ◽  
Gap Formation ◽  
Solidification Defects

Wire rod is produced by hot-rolling a bar of metal coming from a wheel/belt continuous casting process. This kind of process, e.g. Properzi, is an elaborate process in which the molten metal is poured in a cooled rotating mould formed by the groove of a wheel and closed by a belt. In order to better understand the heat transfer phenomenon and solidified bar characteristics, depending on process parameters a three dimensional thermo-mechanical model has been developed. The model, based on the finite-element method, calculates the heat transfer coefficient of the air gap at the metal-mould interface as a function of the size of the gap determined by the bar contraction and wheel and belt thermal deformations. The air gap formation due to metal shrinkage and mould deformation is the main factor which determines the heat extraction. Wheel temperature measurements with thermocouple and belt temperature measurements with an infrared system were carried out to verify model results. Attempts were also made to measure a liquid pool profile using doping with copper rich alloy. The model shows the effect of the casting temperature and the rotation speed on the air gap formation and resulting temperature and stress fields. The model can be applied to issues such as maximising wheel and belt life and minimising solidification defects.

Numerical Simulation on the Liquid Metal Flow of the Acceleration Phase in the Shot Sleeve of Cold Chamber Die Casting Process

2007 ◽  
Vol 561-565 ◽  
pp. 1801-1804
Author(s):  
Jie Yang ◽  
Lang Yuan ◽  
Shou Mei Xiong ◽  
Bai Cheng Liu
Keyword(s):  
Numerical Simulation ◽  
Liquid Metal ◽  
Metal Flow ◽  
Three Dimensional ◽  
Great Influence ◽  
Casting Process ◽  
Shot Sleeve ◽  
Three Dimensional Model ◽  
Acceleration Phase ◽  
Fill Ratio

Slow shot velocity and its acceleration phase in the shot sleeve have great influence on the flow pattern of the liquid metal in the shot sleeve. In this paper, a three-dimensional model based on the SOLA-VOF algorithm was developed and used to simulate the flow of melt in the shot sleeve. The mathematical model was verified by water analog experiments with constant plunger velocities. Based on numerical simulation results, the influences of the plunger acceleration on the wave profile of the liquid metal in the shot sleeve under different fill ratios and sleeve diameters were investigated. The results indicated that in order to avoid air entrapment in the shot sleeve, the optimal acceleration value to the critical slow shot velocity increases with the increase of the fill ratio, and the range of suitable acceleration becomes wider as well. With the same fill ratio, the value of suitable acceleration rises as the plunger diameter increases.

Aperiodic Deformation Occurring as a Result of Thermoplastic Instability of Metals

2007 ◽  
Vol 537-538 ◽  
pp. 541-548 ◽  
Author(s):  
Zoltán Pálmai
Keyword(s):  
Plastic Deformation ◽  
Shear Stress ◽  
Shear Strain ◽  
Three Dimensional ◽  
Experimental Results ◽  
Reverse Effect ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Periodic Fluctuation ◽  
Linear Nature

The author developed a three-dimensional model for the description of fast plastic deformation of metals in the case of cutting. Shear strain occurring as a result of shear stress has a reverse effect on stress, while the temperature of the material is increasing. These counteracting effects may lead to thermomechanic instability, which may result in aperiodic chaotic conditions besides periodic fluctuation due to the non-linear nature of the process. Apart from bifurcation and multi-cycle periodic deformation, the model also describes aperiodic chaotic deformation, which is proven by experimental results.

3D Fem Study of Fluid Flow in the Mould for Billet Continuous Casting

2009 ◽  
Vol 79-82 ◽  
pp. 1269-1272
Author(s):  
Wei Chen ◽  
Bao Xiang Wang ◽  
Yu Zhu Zhang ◽  
Jin Hong Ma ◽  
Su Juan Yuan
Keyword(s):  
Fluid Flow ◽  
Continuous Casting ◽  
Casting Speed ◽  
Three Dimensional ◽  
Casting Process ◽  
Element Model ◽  
3D Fem ◽  
Billet Continuous Casting ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

In this paper, a three-dimensional finite element model is developed to simulate and analyze the turbulent flow in the mould of billet continuous casting. The result shows that if the SEN is used in the continuous casting process, there exists a symmetrical stronger vortex in the middle of the mould and a weaker vortex above the nozzle. The casting speed, the depth and diameter of SEN all have significant effect on the fluid flow field and the turbulent kinetic energy on the meniscus, and then have effect on the billet quality. At the given conditions, the optimum set of parameters is: the casting speed 0.035 , the depth of the SEN 0.1 , the diameter of the SEN 0.025 . Online verifying of this model has been developed, which can be proved that it is very useful to control the steel quality and improve the productivity.

Model of local temperature changes in brain upon functional activation

2004 ◽  
Vol 97 (6) ◽  
pp. 2051-2055 ◽  
Author(s):  
Christopher M. Collins ◽  
Michael B. Smith ◽  
Robert Turner
Keyword(s):  
Brain Temperature ◽  
Human Subjects ◽  
Potential Temperature ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Human Head ◽  
Bioheat Equation ◽  
Three Dimensional Model ◽  
Temperature Changes ◽  
Blood Temperature

Experimental results for changes in brain temperature during functional activation show large variations. It is, therefore, desirable to develop a careful numerical model for such changes. Here, a three-dimensional model of temperature in the human head using the bioheat equation, which includes effects of metabolism, perfusion, and thermal conduction, is employed to examine potential temperature changes due to functional activation in brain. It is found that, depending on location in brain and corresponding baseline temperature relative to blood temperature, temperature may increase or decrease on activation and concomitant increases in perfusion and rate of metabolism. Changes in perfusion are generally seen to have a greater effect on temperature than are changes in metabolism, and hence active brain is predicted to approach blood temperature from its initial temperature. All calculated changes in temperature for reasonable physiological parameters have magnitudes <0.12°C and are well within the range reported in recent experimental studies involving human subjects.

scholarly journals Determination of the coefficient of restitution upon contact of a steel ball with aluminum and steel surfaces

2021 ◽  
Vol 2131 (3) ◽  
pp. 032087
Author(s):  
V G Gusev ◽  
A V Sobolkov ◽  
A V Aborkin
Keyword(s):  
Experimental Studies ◽  
Three Dimensional ◽  
Calculated Data ◽  
High Energy ◽  
Complex Model ◽  
Steel Ball ◽  
Restitution Coefficient ◽  
Discrete Elements ◽  
Three Dimensional Model ◽  
Steel Surfaces

Abstract In this work, experimental studies on the rebound of a steel ball from aluminum and steel surfaces have been carried out. Using the ideology of the method of discrete elements, a three-dimensional model of the process was built. By carrying out multivariate calculations with varying the restitution coefficient and subsequent comparison of experimental and calculated data on the ball rebound height, the actual restitution coefficient for contact pairs “steel - steel” and “steel - aluminum” was determined. The results of the work will be used in the development of a complex model of high-energy ball milling.

A Mathematical Analysis of Directional Solidification of Aqueous Solutions

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Gideon Ukpai ◽  
Boris Rubinsky
Keyword(s):  
Mathematical Model ◽  
Aqueous Solutions ◽  
Mathematical Models ◽  
Directional Solidification ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Design Parameters ◽  
Fundamental Study ◽  
Biological Matter ◽  
Intent To Use

Abstract Horizontal directional solidification techniques have been broadly utilized for the freezing of biological matter under conditions in which the freezing rate during solidification must be controlled and known. Directional solidification is used for diverse applications such as fundamental research on freezing of biological materials, cryopreservation of biological matter, and tissue engineering. This study is motivated by our intent to use directional solidification as a simplified model for the study of three-dimensional (3D) cryoprinting. In evaluating directional solidification in the context of 3D cryoprinting, we realized that current mathematical models of directional solidification are not adequately representative for this purpose, because they are simplified and one-dimensional (1D). Here, we introduce an experimentally verified and more representative two-dimensional (2D) mathematical model of directional solidification that can aid in the fundamental study of freezing of biological matter, in particular during 3D cryoprinting. The mathematical model was used to develop correlations between the freezing rates that a layer of an aqueous solution experiences during directional solidification and the various design parameters such as thickness of the sample and temperature gradients in the substrate. Results show that the freezing rates can be higher than those suggested by the previously used simplified 1D mathematical models. The results can be used for developing simplified models of 3D cryoprinting. In addition, the results suggest that many experimental studies on directional solidification of aqueous solutions and biological matter may require readjustment of analysis, in view of these findings.

Numerical Analysis of Crack Propagation in Silicon Nitride

2011 ◽  
Vol 490 ◽  
pp. 216-225 ◽  
Author(s):  
Waldemar Karaszewski
Keyword(s):  
Numerical Analysis ◽  
Crack Propagation ◽  
Coefficient Of Thermal Expansion ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Contact Fatigue ◽  
High Hardness ◽  
Rolling Contact ◽  
Three Dimensional Model ◽  
Ring Crack

The properties of ceramics, specifically low density, high hardness, high temperature capability and low coefficient of thermal expansion are of most interest to rolling element manufacturers. The influence of ring crack size on rolling contact fatigue failure has been studied using numerical fracture analysis. Such cracks are very often found on ceramic bearing balls and decrease fatigue life rapidly. The numerical calculation are based on a three dimensional model for the ring crack propagation. The stress intensity factors along crack front are analyzed using a three-dimensional boundary element model. The numerical analysis is verified by experimental studies.

scholarly journals Thermodynamic and Experimental Studies on Al Addition of 253MA Steel

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 433 ◽  
Author(s):  
Yandong Li ◽  
Tongsheng Zhang ◽  
Chengjun Liu ◽  
Maofa Jiang
Keyword(s):  
Phase Diagram ◽  
Continuous Casting ◽  
Experimental Studies ◽  
Casting Process ◽  
Al Alloy ◽  
Liquid Region ◽  
Continuous Casting Process ◽  
Nozzle Clogging ◽  
Calphad Technique ◽  
Liquid Phases

To solve the nozzle clogging issue in the continuous casting process of 253MA steel, a method of modifying solid inclusions to liquid phases is proposed. The CALPHAD technique was employed to predict the liquid region of the Al2O3-SiO2-Ce2O3 system. Then a thermodynamic package based on the extracted data during the phase diagram optimization process was developed. This package was then used to compute the appropriate aluminum addition, which was 0.01% in 253MA steel. The Si-Al alloy was chosen as the deoxidant according to the thermodynamic analysis. The solid inclusions were ultimately modified to liquid phases at 1500 °C when cerium was added through the equilibrium experiments in a MoSi2 tube furnace.

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