Origin of Heat Transfer Anomaly and Solidifying Shell Deformation of Peritectic Steels in Continuous Casting.

Suzuki, Mikio; Yu, Chong-Hee; Sato, Hidenori; Tsui, Yuji; Shibata, Hiroyuki; Emi, Toshihiko

doi:10.2355/isijinternational.36.suppl_s171

Cited by 29 publications

(17 citation statements)

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“…Heat transfer and solidification of steels during continuous casting process have been extensively studied 7, 24, 25, 28, 31–34. However, the effect of the uniformity of cooling intensity in the transverse direction on the center macro‐segregation was not paid much attention to.…”

Section: Mathematical Modeling On Mitigating Center Macro‐segregationmentioning

confidence: 99%

Study on Mitigating Center Macro‐Segregation During Steel Continuous Casting Process

Long

Chen

2011

steel research int.

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In the current paper, Methods of enlarging the area for the distribution of segregation solutes were introduced to mitigate center macrosegregation in steel billets and steel slabs during continuous casting process, which cost less and have significant effect. The location of center macro-segregation is relative to the shape of liquid-core at the solidification end during steel continuous casting. A method of dissymmetrical cooling on different surfaces, by which the area for the precipitation of segregation solutes was enlarged, was introduced to mitigate the center macro-segregation in billets during continuous casting process. Method of optimizing the uniformity of solidified shell in the transverse direction was introduced to mitigate the center macro-segregation in steel slabs. The uniform cooling intensity along the transverse direction guaranteed a regular solidification end in the continuous casting slab, which aided in the effective application of dynamic soft reduction technology. A relevant 2-D heat transfer model was developed for the optimization of uniform solidification. The current method was applied to the industrial slab continuous casting using the heat transfer model. The results indicated a better industrial slab quality with much less center macro-segregation after the use of the method.

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Section: Mathematical Modeling On Mitigating Center Macro‐segregationmentioning

confidence: 99%

Study on Mitigating Center Macro‐Segregation During Steel Continuous Casting Process

Long

Chen

2011

steel research int.

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“…It is mentioned that the shrinkage values reported by the authors some time ago 7) are of similar magnitude and show the peak at about 0.1 mass% carbon. Also Emi et al 8) find the shrinkage peak at the same carbon content.…”

Section: Effect Of Carbon Content On Ingot Shrinkagementioning

confidence: 82%

“…Investigations have been carried out on lead, 1,2) aluminum, 3) copper, 4) cast iron 5) and steel. [6][7][8] It is well known that apart from the casting conditions the chemical analysis has a considerable influence on the phenomena occurring in the mold. Certain steel grades with about 0.1 mass% carbon have been found to be more sensitive to surface defects, surface roughness, geometrical defects and breakouts than grades with elevated carbon contents.…”

Section: Introductionmentioning

confidence: 99%

Shrinkage of Round Iron-Carbon Ingots during Solidification and Subsequent Cooling

Harste

Schwerdtfeger

2003

ISIJ International

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The shrinkage of round iron-carbon ingots during solidification and subsequent cooling has been investigated with hot model experiments involving round ingots of 50 kg of steel. Three motor driven sensors made it possible to measure the shrinkage without deformation of the shell starting a few seconds after casting.The temperature distribution was computed with a thermal model. Thereafter, a mechanical model was applied to compute the shrinkage finding satisfactory agreement between the measured and computed shrinkage-time curves. Data are given on the effect of carbon content on the shrinkage of steel and it was confirmed that there is a shrinkage peak at about 0.1 mass% carbon.KEY WORDS: shrinkage of carbon steels; solidification of carbon steels; peritectic steels. crease of density) associated with the d/g transformation. During solidification of an ingot (strand) the d/g transformation occurs layerwise, due to the temperature gradient, Fig. 2. Consequently, there is a dϩg band in the solid shell with steep change of the thermal contraction value, moving inwards with time, and this effect will enhance the formation of thermal stress. Hence, the quantitative treatment of the shrinkage of steel during solidification and of the associated formation of stress is of high interest for various reasons.We have performed extensive shrinkage measurements on iron-carbon alloys and developed a corresponding mathematical model for the computation of displacements, strains and stresses originating during solidification and subsequent cooling. The results are reported in the following. Experimental Method for Shrinkage MeasurementsAs has already been mentioned shrinkage* 1 measurements under continuous casting conditions are extremely difficult or even impossible, but they are feasible on standing ingots. The experimental setup used in the present study is shown in Figs. 3 and 4. It consists of an instrumented mold with feeding channel installed within the chamber of a vacuum induction furnace. The round mold is made of grey cast iron and has a height of 470 mm, an I.D. of 140 mm (at half height) and an O.D. of 240 mm. The mass of the cast steel melts is 50 kg.The surface position of the solidifying ingot is determined with a contact mechanism, Fig. 4, using an alumina sheath as a sensor and an inductive transducer to record its position. In the early stages of solidification the shell is thin and soft, and the contact of the sensor must be gentle to avoid deformation of the surface. Therefore, the sensor is not pressed permanently against the ingot but is driven by a motor towards the surface and then withdrawn immediately after contact has been made. The contact is recorded electrically via a platinum bead located at the tip of the sheath and connected, with a platinum wire, to the control unit of the motor. So, the sensor moves towards the ingot and the platinum bead touches the ingot surface. The control unit receives a signal to change the polarity of the power supply of the motor and the motor rotates in reverse dire...

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“…Fig. 4 shows the schematic presentation of the mechanical properties of carbon steel and the δ-γ transformation range for middle carbon steels during solidification [4], in which T l denotes the liquid temperature. What's more, for peritectic medium carbon steels, the deformation of the shell caused by shrinkage due to the transformation of δ to γ during and just after solidification is responsible for the formation of the surface roughness, resulting in local air gaps and heat transfer anomaly.…”

Section: Reasons Of Longitudinal Crack Formationmentioning

confidence: 99%

Longitudinal surface cracks of thin slabs

Sun

Wang

et al. 2010

Int J Miner Metall Mater

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Based on the production practice of medium carbon thin slabs in the CSP plant, the reasons and influencing factors for the formation of longitudinal cracks were investigated, and some industrial measures were taken to eliminate the cracks. The results show that the efficient solutions to reduce longitudinal cracks are improving the performance of the mold powder, stabilizing the mold heat flux, and maintaining a proper taper of the mold during casting. Proper pouring temperature and secondary cooling also play important roles in preventing longitudinal surface cracks.

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Origin of Heat Transfer Anomaly and Solidifying Shell Deformation of Peritectic Steels in Continuous Casting.

Cited by 29 publications

References 1 publication

Study on Mitigating Center Macro‐Segregation During Steel Continuous Casting Process

Study on Mitigating Center Macro‐Segregation During Steel Continuous Casting Process

Shrinkage of Round Iron-Carbon Ingots during Solidification and Subsequent Cooling

Longitudinal surface cracks of thin slabs

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