Influence of External Action on the Internal Structure of Continuously Cast Slab Produced from Tube Steel

The paper compares the internal structure of two continuously cast slabs with a section of 300 × 2600 mm from a tube steel of the strength class K60, one of which is molded with a soft reduction, and the other is without external influence. A comparative analysis of the structure of two templates showed that the location of areas with an increased metal pickle ness in the axial part of the templates varies. On the template from a slab cast without reduction, this section is below the geometric center of the work-piece in thickness, at a distance of 49.2% from the underside, that is, the "lower" asymmetry of the slab structure is observed. On the template from the slab cast off with soft reduction, the area with an increased pickle-ness is located above the middle of the work-piece: at a distance of 51.7% of the side of the large radius, an "upper" asymmetry of the slab structure is formed. Consequently, as a result of the external action on the cast work-piece, the location of the axial sponginess, relative to the geometric centre of the slab, is changed by moving from the lower to the upper half of the work-piece. The metal of the axial part of the reduced slab has a denser structure, the degree of development of axial looseness in the metallographic evaluation is reduced by an average of 0.5 points. The work shows the change in the content of chemical elements along the thickness of slabs. In the reduced metal, the maximum value of the degree of zonal inhomogeneity of the most impurities is higher than in the metal without external influence. This is explained by the fact that, as a result of reduction, the zone of location of the axial chemical heterogeneity in the slab becomes smaller in width.

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Influence of technology parameters of free-cutting steel continuous casting on the billet internal structure

Ferrous Metallurgy Bulletin of Scientific Technical and Economic Information ◽

10.32339/0135-5910-2020-2-139-142 ◽

2020 ◽

Vol 76 (2) ◽

pp. 139-142

Author(s):

A. T. Kunakbaeva ◽

A. M. Stolyarov ◽

M. V. Potapova

Keyword(s):

Regression Analysis ◽

Continuous Casting ◽

Internal Structure ◽

Sulfur Content ◽

Manganese Content ◽

High Quality ◽

Correlation And Regression Analysis ◽

Cutting Steel ◽

Continuously Cast

Free-cutting steel gains specific working properties thanks to the high content of sulfur and phosphorus. These elements, especially sulfur, have a rather high tendency to segregation. Therefore, segregation defects in free-cutting steel continuously cast billets can be significantly developed. The aim of the work was to study the influence of the chemical composition of freecutting steel and casting technological parameters on the quality of the macrostructure of continuously cast billets. A metallographic assessment of the internal structure of cast metal made of free-cutting steel and data processing by application of correlation and regression analysis were the research methods. The array of production data of 43 heats of free-cutting steel of grade A12 was studied. Steel casting on a five-strand radial type continuous casting machine was carried out by various methods of metal pouring from tundish into the molds. Metal of 19 heats was poured with an open stream, and 24 heats – by a closed stream through submerged nozzles with a vertical hole. High-quality billets had a cross-sectional size of 150×150 mm. The macrostructure of high-quality square billets made of free-cutting steel of A12 grade is characterized by the presence of central porosity, axial segregation and peripheral point contamination, the degree of development of which was in the range from 1.5 to 2.0 points, segregation cracks and strips – about 1.0 points. In the course of casting with an open stream, almost all of these defects are more developed comparing with the casting by a closed stream. As a result of correlation and regression analysis, linear dependences of the development degree of segregation cracks and strips both axial and angular on the sulfur content in steel and on the ratio of manganese content to sulfur content were established. The degree of these defects development increases with growing of sulfur content in steel of A12 grade. These defects had especially strong development when sulfur content in steel was of more than 0.10%. To improve the quality of cast metal, it is necessary to have the ratio of the manganese content to the sulfur content in the metal more than eight.

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Seismotectonic setting of the earthquake of august 7, 2016 and its aftershocks

Физика земли ◽

10.31857/s0002-333720192156-167 ◽

2019 ◽

pp. 156-167 ◽

Cited By ~ 1

Author(s):

I. A. Sanina ◽

G. N. Ivanchenko ◽

E. M. Gorbunova ◽

N. L. Konstantinovskaya ◽

M. A. Nesterkina ◽

...

Keyword(s):

Main Shock ◽

Satellite Image ◽

External Influence ◽

Visual Interpretation ◽

Seismogenic Structure ◽

Vertical Movements ◽

Southern Boundary ◽

East European ◽

Alpine Zone ◽

Axial Part

An earthquake with magnitude 4.8 hit the vicinity of Mariupol close to the southern boundary of the East European Platform (EEP) on August 7, 2016. The main event was followed by the aftershocks with magnitudes ranging from 2.2 to 3.9 which lasted for five days. The region experiences external influence from the neotectonically active Alpine zone resulting in intraplate deformations, horizontal and vertical movements of the Earth’s surface, and seismicity. The sources of the main shock and aftershocks are located within the block bounded by the neotectonically active Maloyanisol, Kalmius, and Primorsky faults. A seismogenic structure traced by the submeridional Kalchik lineament zone is identified in the axial part of the block by the combined analysis of geological and geophysical data and visual interpretation of the satellite image. This neotectonically active zone hosts the epicenters of the main event and most of the aftershocks.

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Model for Predicting the Machinability of Continuously Cast and Subsequently Rolled Steel Using the Artificial Neural Network

Tehnički glasnik ◽

10.31803/tg-20210619190926 ◽

2021 ◽

Vol 15 (3) ◽

pp. 381-386

Author(s):

Miha Kovačič ◽

Shpetim Salihu ◽

Uroš Župerl

Keyword(s):

Neural Network ◽

Artificial Neural Network ◽

Production Process ◽

Chemical Elements ◽

Cast Steel ◽

Model Development ◽

Cutting Speed ◽

Steel Production ◽

Continuously Cast ◽

Artificial Neural

The paper presents a model for predicting the machinability of steels using the method of artificial neural networks. The model includes all indicators from the entire steel production process that best predict the machinability of continuously cast steel. Data for model development were obtained from two years of serial production of 26 steel grades from 255 batches and include seven parameters from secondary metallurgy, four parameters from the casting process, and the content of ten chemical elements. The machinability was determined based on ISO 3685, which defines the machinability of a batch as the cutting speed with a cutting tool life of 15 minutes. An artificial neural network is used to predict this cutting speed. Based on the modelling results, the steel production process was optimised. Over a 5-month period, an additional 39 batches of 20MnV6 steel were produced to verify the developed model.

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Tidal dissipation modelling in gaseous giant planets at the time of space missions

10.5194/epsc2021-762 ◽

2021 ◽

Author(s):

Hachem Dhouib ◽

Stéphane Mathis ◽

Florian Debras ◽

Aurélie Astoul ◽

Clément Baruteau

Keyword(s):

Internal Structure ◽

Differential Rotation ◽

Giant Planets ◽

Solid Core ◽

Large Radius ◽

Mixing Zone ◽

Convective Envelope ◽

Tidal Dissipation ◽

Hot Jupiters ◽

Tidal Waves

Gaseous giant planets (Jupiter and Saturn in our solar system and hot Jupiters around other stars) are turbulent rotating magnetic objects that have strong and complex interactions with their environment (their moons in the case of Jupiter and Saturn and their host stars in the case of hot Jupiters/Saturns). In such systems, the dissipation of tidal waves excited by tidal forces shape the orbital architecture and the rotational dynamics of the planets. During the last decade, a revolution has occurred for our understanding of tides in these systems. First, Lainey et al. (2009, 2012, 2017) have measured tidal dissipation stronger by one order of magnitude than expected in Jupiter and Saturn. Second, unexplained broad diversity of orbital architectures and large radius of some hot Jupiters are observed in exoplanetary systems. Finally, new constraints obtained thanks to Kepler/K2 and TESS indicate that tidal dissipation in gaseous giant exoplanets is weaker than in Jupiter and in Saturn (Ogilvie 2014, Van Eylen et al. 2018, Huber et al. 2019). Furthermore, the space mission JUNO and the grand finale of the CASSINI mission have revolutionized our knowledge of the interiors of giant planets. We now know, for example, that Jupiter is a very complex planet: it is a stratified planet with, from the surface to the core, a differentially rotating convective envelope, a first mixing zone (with stratified convection), a uniformly rotating magnetised convective zone, a second magnetized mixing zone (the diluted core, potentially in stratified convection) and a solid core (Debras & Chabrier 2019). So far, tides in these planets have been studied by assuming a simplified internal structure with a stable rocky and icy core (Remus et al. 2012, 2015) and a deep convective envelope surrounded by a thin stable atmosphere (Ogilvie & Lin 2004) where mixing processes, differential rotation and magnetic field were completely neglected. Our objective is thus to predict tidal dissipation using internal structure models, which agree with these last observational constrains. In this work, we build a new ab-initio model of tidal dissipation in giant planets that coherently takes into account the interactions of tidal waves with their complex stratification induced by the mixing of heavy elements, their zonal winds, and (dynamo) magnetic fields. This model is a semi-global model in the planetary equatorial plane. We study the linear excitation of tidal magneto-gravito-inertial progressive waves and standing modes. We take into account the buoyancy, the compressibility, the Coriolis acceleration (including differential rotation), and the Lorentz force. The tidal waves are submitted to the different potential dissipative processes: Ohmic, thermal, molecular diffusivities, and viscosity. We here present the general formalism and the potential regimes of parameters that should be explored. The quantities of interest such as tidal torque, dissipation, and heating are derived. This will pave the way for full 3D numerical simulations that will take into account complex internal structure and dynamics of gaseous giant (exo-)planets in spherical/spheroidal geometry. &#160;

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Influence of Soft Reduction with One-piece Rolls on Center Segregation in Continuously Cast Slabs.

ISIJ International ◽

10.2355/isijinternational.31.1400 ◽

1991 ◽

Vol 31 (12) ◽

pp. 1400-1407 ◽

Cited By ~ 24

Author(s):

Shigeaki Ogibayashi ◽

Masayuki Kobayashi ◽

Mamoru Yamada ◽

Tatsuo Mukai

Keyword(s):

Soft Reduction ◽

Continuously Cast

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Effect of soft reduction on the structure of continuously-cast slabs

Metallurgist ◽

10.1007/s11015-009-9126-3 ◽

2009 ◽

Vol 53 (1-2) ◽

pp. 98-104 ◽

Cited By ~ 2

Author(s):

Yu. A. Samoilovich

Keyword(s):

Soft Reduction ◽

Continuously Cast

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Improvement of Center Segregation in Continuously Cast Blooms by Convex Roll Soft Reduction

TMS 2019 148th Annual Meeting & Exhibition Supplemental Proceedings - The Minerals, Metals & Materials Series ◽

10.1007/978-3-030-05861-6_5 ◽

2019 ◽

pp. 51-61

Author(s):

Liang Li ◽

Xiao Zhao ◽

Peng Lan ◽

Zhanpeng Tie ◽

Haiyan Tang ◽

...

Keyword(s):

Soft Reduction ◽

Continuously Cast

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Stellar Convective Cores

Symposium - International Astronomical Union ◽

10.1017/s0074180900238321 ◽

1998 ◽

Vol 185 ◽

pp. 73-80

Author(s):

I.W. Roxburgh

Keyword(s):

Internal Structure ◽

Binary Stars ◽

Nuclear Reactions ◽

Chemical Elements ◽

Theoretical Models ◽

Large Mass ◽

Subsequent Evolution ◽

Mixing Processes ◽

Processed Material ◽

Nuclear Burning

The internal structure of stars is governed by hydrostatic support, the distribution of the chemical elements, the transport of energy by radiation and convection, and the liberation of energy by nuclear reactions. The evolution of stars is primarily determined by the changing composition due to the nuclear burning of elements in the central parts of the star, and the redistribution of the products of these reactions by mixing processes. The dominant mixing process is convection: it governs the extent of the mixed cores in moderate and large mass main sequence stars and their subsequent evolution, it mixes nuclear processed material into the envelopes of giants affecting the composition of material ejected into the interstellar medium, thereby affecting the chemical (and luminosity) evolution of galaxies. Understanding convection is essential if one is to understand the evolution of stars. Here I am concerned with convection in stellar cores and in particular with the extension of these cores by the penetration of convective motions into the surrounding stable layers affecting the internal structure and enlarging the chemically mixed region, which in turn affects the subsequent evolution. I briefly discuss a number of approaches to this problem: isochrone fitting of clusters and binary stars; simple theoretical models, the integral constraint, numerical simulation and what we can hope to get from asteroseismological observations of individual stars and of clusters and stellar groups.

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