scholarly journals Stress-strain state of metal in deformation zone during production of steel section billets on the unit of combined continuous casting and deformation. Report 2

2020 ◽  
Vol 63 (9) ◽  
pp. 730-734
Author(s):  
O. S. Lekhov ◽  
A. V. Mikhalev
Keyword(s):  
Stress State ◽  
Continuous Casting ◽  
Cross Sections ◽  
Deformation Zone ◽  
Cast Slab ◽  
Equivalent Stresses ◽  
Steel Slab ◽  
Characteristic Lines ◽  
Continuously Cast ◽  
Steel Section

Stress state of metal in deformation zone during introduction of the separating collars of the grooved die into continuously casted steel slab was calculated for production of section billets on the unit of combined continuous casting and deformation. Calculation of axial, tangential and equivalent stresses arising in deformation zone of metal was made in four sections of deformation zone and its results are presented in specific points and lines. View of the section of deformation zone and location of specific points are provided. The stress state of metal in zone of cyclic deformation at formation of three steel section billets from continuously cast slab by separating collars of grooved die on the unit of combined continuous casting and deformation was determined by solving extensive problem of elasticity with the finite element method using the ANSYS package. The results of calculation of axial, tangential and equivalent stresses according to Mises in deformation zone are given in form of graphs and tables for working surfaces in four cross sections. The values and regularities of distribution of these stresses along the length and width of deformation zone were determined. The character of axial stresses distribution by characteristic lines located along the length of deformation zone is shown. Values of the highest compressive and tensile axial stresses arising in deformation zone during introduction of separating collars of grooved were obtained for the unit of combined continuous casting and deformation.

scholarly journals Stress-strain state of metal in deformation zone during production of steel section billets on the unit of combined continuous casting and deformation. Report 1

2020 ◽  
Vol 63 (7) ◽  
pp. 548-553
Author(s):  
O. S. Lekhov ◽  
A. V. Mikhalev
Keyword(s):  
Continuous Casting ◽  
Cross Sections ◽  
Deformation Zone ◽  
Strain State ◽  
Cast Slab ◽  
Stress Strain ◽  
Stress Strain State ◽  
Characteristic Points ◽  
Continuously Cast ◽  
Longitudinal Division

Volumetric problem of determining stress-strain state of metal in deformation zone during forming of three section billets from the slab by separating collars of grooved strikers on the unit of combined continuous casting and deformation was set and solved. The expediency of using such unit was justified for longitudinal division mation are given for St3sp steel. The solid-state finite elements used in calculation of stress-strain state of metal in deformation zone and dimensions of the grid are described. The results of calculation of stress-strain state of metal in deformation zone were obtained by solving the problem of elasticity by the finite element method in volumetric formulation. The results of calculation of displacements and stresses in deformation zone are given in form of graphs and tables by working surfaces in four cross sections and are presented for characteristic points. Values and regularities of distribution of axial displacements in width and length of deformation center were determined during introduction of strikers separating collars into continuously cast slab in production of three section steel billets on the unit of combined continuous casting and deformation.

Reduction in Surface Defect in Continuous Cast Slab through Intervention in Process Parameters

2020 ◽  
Vol 978 ◽  
pp. 91-96
Author(s):  
Snehangshu Roy ◽  
R.K. Singh ◽  
Kiran Kumar Keshari ◽  
N. Pradhan ◽  
M. Kumar ◽  
...  
Keyword(s):  
Continuous Casting ◽  
Surface Defects ◽  
Systematic Investigation ◽  
Route Optimization ◽  
Critical Parameters ◽  
Hot Strip Mill ◽  
Cast Slab ◽  
Process Route ◽  
Mould Flux ◽  
Continuously Cast

Occurrence of defects like crack on the surface of the cast products has long been recognized as a critical challenge for steelmakers in the continuous casting. Cracks on the surface can severely reduce yield and required further operations like salvage and scarfing. Depending on the severity of defect slabs can be diverted or in worst cases a slab can be rejected altogether if the defect cannot be removed by surface conditioning. Rourkela Steel Plant (RSP) of Steel Authority of India Limited (SAIL) produces continuously cast slabs as feed material for plate mills and hot strip mill. Sometimes the slabs produced through continuous casting are faced issues intermittently due to presence surface defects like midface longitudinal cracks (LC) and transverse edge crack (EC) etc. A systematic investigation of the operating parameters of these casters e.g. monitoring of oscillation parameters, slabs and mould flux, simulation and analysis of fluid flow inside mould, steel chemistry and role of dissolve gases in steel. Based on the investigation critical parameters responsible for crack formation have been identified and key areas identified where modification need to be done. Modifications has been done in terms of mould flux addition practice, optimization of the grade chemistry, optimization of process route, optimization of casting speed, checking of strand thermal profile, mould & machine allignment etc. It was observed that the crack incidences are significantly lower after the modifications were done.

Precipitation in Surface Zone of Continuously-Cast Slab of ULC/IF Steel Microalloyed with Titanium

2014 ◽  
Vol 782 ◽  
pp. 73-80 ◽  
Author(s):  
Margita Longauerová ◽  
Maria Hurakova ◽  
Svätoboj Longauer
Keyword(s):  
Continuous Casting ◽  
Drawing Rate ◽  
Surface Zone ◽  
If Steel ◽  
Slab Surface ◽  
Cast Slab ◽  
Surface Areas ◽  
Elliptical Shape ◽  
Continuously Cast ◽  
Mean Size

The aim of this work was to analyze the morphology and distribution of the microalloy precipitates in the slab surface zone of ULC/IF steel microalloyed with titanium. The slab was made by continuous casting using two different slab pulling rates. Transient slabs were pulled with pulling rate 0.4 m/min at the start and 0.8 m/min at the end of the slab. It was confirmed that morphology of the particles evaluated in the surface areas of slab were globular, cubical or elliptical shape and have been identified as of TiS, TiN and TiC. At the lower drawing rate particles from the middle cut-out from an area with coarse ferritic grains at the slab surface attained an mean size of 2r = 41.8 nm, and from an area with fine ferritic grains they attained an mean size of 2r = 32.5 nm. At the higher drawing rate particles in the middle cut-out attained an mean size of 2r= 63.5 nm. The coarser particles were found in areas with coarse ferrite grains and at higher pulling speed.

Star Cracks in Continuously Cast Deep-Drawing Tin Steel Slab

2014 ◽  
Vol 782 ◽  
pp. 235-238
Author(s):  
Jaroslav Duška ◽  
Gabriel Grimplini ◽  
Marek Molnár ◽  
Lucia Hrabčáková ◽  
Atila Drotár
Keyword(s):  
Deep Drawing ◽  
Small Radius ◽  
Internal Quality ◽  
Cast Slab ◽  
Steel Slab ◽  
Continuous Slab ◽  
Slab Casting ◽  
Continuously Cast ◽  
Gradual Expansion

The final quality of flat products is directly related to surface and internal quality of continuously cast slabs. This aspect is very important especially in case of IF and deep-drawing tin grades, in which even the smallest defects can cause problem in the final processing of the material, especially during forming by stamping, when the material fails. This work is devoted to the analysis of the surface defect of star crack type. The presence of defect was visually detected after scarfing process during removal of surface layer on the small radius side of the slab. This type of defect occurs particularly in cases, when steel is contaminated by copper in the process of continuous slab casting. In view of the copper melting point (1083°C) and the surface temperature of the cast slab shell at the mold exit (about 1200°C) in the process of steel cooling at continuous casting, Cu penetrates along the boundaries of primary austenitic grain, or separate particles are precipitated at the grain boundaries. Initial cracks are formed in the area of primary cooling in the mold. Thermal and mechanical stresses acting in the surface area of slab shell when the slab passes thorough the rollers of secondary cooling cause gradual expansion of crack defects along boundaries of grains contaminated by copper.

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

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.

Improvement of Continuously Cast Slab Surface and Performance of Rolling the Slab Free from Surface Conditioning

1981 ◽  
Vol 67 (8) ◽  
pp. 1229-1235 ◽  
Author(s):  
Minoru KITAMURA ◽  
Tosiyuki SOEJIMA ◽  
Sinzi KOYAMA ◽  
Yosihiro MATUDA ◽  
Junji ABU ◽  
...  
Keyword(s):  
Slab Surface ◽  
Cast Slab ◽  
Surface Conditioning ◽  
Continuously Cast ◽  
And Performance

Effect of Strain Rate on Nb(C,N) Precipitation in Micro Alloy Steel Slab

2012 ◽  
Vol 535-537 ◽  
pp. 633-638 ◽  
Author(s):  
Zheng Hai Zhu ◽  
Sheng Tao Qiu
Keyword(s):  
Continuous Casting ◽  
Strain Rate ◽  
Alloy Steel ◽  
Casting Speed ◽  
Casting Process ◽  
Continuous Casting Process ◽  
Precipitation Model ◽  
Strain And Strain Rate ◽  
Steel Slab

It was analyzed by strain-induced precipitation model that Nb(C,N) precipitation in micro alloy steel slab was effected by strain rate during continuous casting process. The results are as follows: The changing of casting speed could effect the time for 5%precipitation of Nb(C,N), which was decreasing with increasing casting speed at certain temperature and strain rate. Slab strain and strain rate were too small in bending zone and leveling zone. The effect of slab strain rate on Nb(C,N) precipitation could be ignore when Nb(C,N) precipitation in continuous casting process was studied.

Deformation distortions of geometric form tube blanks in the process of drilling holes

2021 ◽  
pp. 104-110
Author(s):  
A.N. Isaev ◽  
S.V. Vlaskin ◽  
V.A. Lebedev ◽  
M.D. Gavrilenko
Keyword(s):  
Stress State ◽  
Wall Thickness ◽  
Cross Sections ◽  
Theoretical Studies ◽  
Geometric Form ◽  
Axisymmetric Stress ◽  
Axisymmetric Stress State ◽  
Elastic Plastic ◽  
The Cross

The influence of deviations of the shape of the cross-sections of pipes from roundness on the axisymmetric stress state and taking this factor into account in theoretical studies and methods for solving problems of mandrel drilling in the elastic-plastic mode are considered. The features of the choice of tubular blanks, which help to reduce the unevenness of deformation and increase the accuracy of processing in the process of mandrel drilling, are revealed. Recommendations are given for eliminating the variance in wall thickness of blanks at the stage of their preparation for the mandrel operation.

Influence of the configuration of the submerged entry nozzle inner channel and electromagnetic effect within its length on the qualitative distribution of metal flows during continuous casting of steel

2021 ◽  
pp. 17-22
Author(s):  
A. Yu. Tretyak ◽  
◽  
Qiang Wang ◽  
Chun-Lei Wu ◽  
E. I. Shifrin ◽  
...  
Keyword(s):  
Quality Control ◽  
Continuous Casting ◽  
Submerged Entry Nozzle ◽  
Electromagnetic Stirring ◽  
Continuous Casting Of Steel ◽  
Electromagnetic Effect ◽  
Inner Surface ◽  
Continuously Cast ◽  
Inner Channel ◽  
Research Show

Today, the most promising and effective method of quality control of the continuously cast billets is electromagnetic stirring of the melt. In this case, an important component is the effect of the stirring on the jet in the nozzle. Moreover, as research has shown, this method is highly dependent on the configuration of the inner channel of the nozzle. Research have shown that positive or negative taper of the inner surface of the nozzle allows to obtain different results after applying EMS. Taper control completely changes the pattern of the melt flow and its deceleration in the mold, especially when it is casting of large billets. The results of the research show that minor changes in the taper of the nozzle significantly increase the effect of EMS implementation, which is observed already at 0.27 % of positive the taper and increases to 0.54%.

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