Thermal soft reduction in continuously cast slabs

1993 ◽  
Vol 173 (1-2) ◽  
pp. 299-304 ◽  
Author(s):  
P. Sivesson ◽  
C.-M. Raihle ◽  
J. Konttinen
2021 ◽  
Vol 316 ◽  
pp. 468-472
Author(s):  
A.M. Stolyarov ◽  
Ye.A. Buneyeva ◽  
M.V. Potapova

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.


1991 ◽  
Vol 31 (12) ◽  
pp. 1400-1407 ◽  
Author(s):  
Shigeaki Ogibayashi ◽  
Masayuki Kobayashi ◽  
Mamoru Yamada ◽  
Tatsuo Mukai

1994 ◽  
Vol 80 (1) ◽  
pp. 42-47 ◽  
Author(s):  
Kohichi ISOBE ◽  
Hirobumi MAEDE ◽  
Kiyomi SYUKURI ◽  
Satoru SATOU ◽  
Takashi HORIE ◽  
...  

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 9
Author(s):  
Liang Li ◽  
Zhonghua Zhang ◽  
Ming Luo ◽  
Bo Li ◽  
Peng Lan ◽  
...  

Based on the Ø195 mm round bloom continuous casting of oil pipe steel, a two dimensional thermal-mechanical coupled model has been developed to investigate the deformation behavior of round bloom during soft reduction (SR) in the reduction force mode. Good agreement was achieved in surface temperature, shell thickness and contact zone width from modeling and measurement. Under the same reduction force, the reduction amount of round bloom at the front unit is much larger than back unit. Moreover, due to its higher temperature and lower center solid fraction, the deformation penetration before solidification is much stronger than that after solidification. Considering the limitation of the round bloom ovality, the maximum allowable force in reduction unit is calculated. According to the simulation results, a multi-unit soft reduction plan was proposed and carried out on the Ø195 mm round bloom. After the reduction process of No.1 to No.3 withdrawal units, the shrinkage porosity in the center of the round bloom was almost vanished, while the number and size of spot segregation were significantly reduced. Moreover, the oil pipe produced by the round bloom with SR got a better resistance to sulfide stress corrosion (SSC). It indicates that SR is an effective technology for the round bloom to control the shrinkage porosity and spot segregation in the continuous casting.


2020 ◽  
Vol 63 (1) ◽  
pp. 19-26
Author(s):  
E. N. Smirnov ◽  
V. A. Sklyar ◽  
D. I. Bogadevich ◽  
A. N. Smirnov ◽  
V. A. Belevitin

Aside from electromagnetic stirring, casting with low superheat and intensive cooling of the strand in the upper range of secondary cooling zone, Mechanical Soft Reduction (MSR) has proved, above all, to be very effective in reducing segregation and axial porosity in continuously cast billet. Implementation of MSR technology in the production of continuously cast billets has a number of features that are due to their square shape. In this case, particularly promising is the use of blocks of segment design, so called pinch-roll segment. The presence in CCM line of MSR block of such design allows to implement a two-stage deformation scheme. The paper proposes a new two-stage scheme of MSR technology realizing the combined deformation on the basis of cobbing in vertical plane and shearing relative displacement of the faces at the first stage, and at the second stage – deformation on the basis of cobbing in vertical plane. This approach additionally helps to correct deformations of the profile cross section, namely the rhomboidity defect. We present the results of a comparative study using physical modeling methods to assess the contribution of additional shear relative displacement of faces in the horizontal plane to the overall efficiency of MSR technology of continuous casting. The use of a flat model in conjunction with the proposed form of deforming rolls and a combination of modeling materials allowed to achieve a good similarity in geometric criterion, as well as in the criterion of stress ratio equivalence arising at the interface of crystallization front. The obtained experimental data helps to develop ideas about the mechanisms of additional positive effect from the application of shear action. In particular, the deformation of metal surface and adjacent layers of the billet in the rolls with a special above-described profiling will improve their quality due to the occurrence of shear deformations intensifying the process of collapse of subcortical bubbles, “healing” of microcracks, etc. In turn, the artificial creation of torque effect in cross section of the billet will contribute to the occurrence of shear deformations in the crystallized “bridges” of axial liquid-solid region of the ingot, thereby intensifying the process of their destruction and improving the quality of the billet’s macrostructure.


2007 ◽  
Vol 14 (5) ◽  
pp. 13-17 ◽  
Author(s):  
Yong Chen ◽  
Gui-jun Li ◽  
Su-bo Yang ◽  
Miao-yong Zhu

1997 ◽  
Vol 83 (1) ◽  
pp. 36-41 ◽  
Author(s):  
Shigeaki OGIBAYASHI ◽  
Ryoji NISHIHARA ◽  
Satoshi SATOH

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