Analysis and Application of Soft Reduction Amount for Bloom Continuous Casting Process

Ji, Cheng; Luo, Shaohua; Zhu, Miaoyong

doi:10.2355/isijinternational.54.504

Cited by 71 publications

(51 citation statements)

References 26 publications

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“…The synchrotron experimental procedure has been described in previous publications [8,14,16] and is schematized in Figure 1. It consisted of the specimen being held in a square, hollowed out, 200 µm thick Al2O3 mould sandwiched in between two 100 µm thick sapphire plates and held in between two boron nitride plates.…”

Section: Methodsmentioning

confidence: 99%

“…On the other hand, external deformation can be beneficial such as the application of a 'soft reduction', a small rolling reduction (e.g. a few % strain) near to the end of the sump to compensate for solidification shrinkage and reduce centreline segregation and porosity [6][7][8]. Despite this importance, there remains only limited understanding of the mechanical behaviour of the mushy-zone in steels and, in particular, of their microstructural response to load and how this leads to defects.…”

Section: Introductionmentioning

confidence: 99%

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Dilatancy in semi-solid steels at high solid fraction

et al. 2017

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The study of mushy-zone deformation in steels is important for limiting defect formation in continuous casting. Here, we use in situ synchrotron radiography to quantify the shear deformation mechanisms of an equiaxed carbon steel at a solid fraction >0.9 and to understand how these mechanisms lead to casting defects. We show that the grain assembly undergoes shear-induced dilation (Reynolds' dilatancy) which opens liquid-filled fissures and cracks at high solid fraction. We further show a complex interaction between grain rearrangement, grain deformation and local coarsening, where rearrangement reduces the grain-grain contact area and coordination number which alters the stress network and also drives coarsening as grains move apart.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dilatancy in semi-solid steels at high solid fraction

et al. 2017

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“…In the secondary cooling zones, the heat of the strand is taken away by the cooling water, roll contact, and radiation. Therefore, the heat flux in secondary cooling was calculated as follows:

q_{\sec}^{i} = h_{\sec}^{i} \cdot (T_{s u r f} - T_{a m b})

\begin{array}{l} center & h_{\sec}^{i} = α_{i} W_{i}^{0.55} \cdot false(1 - 0.0075 T_{w} false) + \frac{h_{c}^{i} \cdot N_{R}^{i} \cdot R_{l}^{i}}{Z_{L}^{i}} \\ center & + σ \cdot ϵ \cdot false(T_{s u r f} + T_{a m b} false) \cdot false({T_{s u r f}}^{2} + {T_{a m b}}^{2} false) \end{array}

where, i denotes the i th cooling zone;

q_{\sec}^{i}

is the heat flux, MW m −2 ,

h_{\sec}^{i}

is the effective heat transfer coefficient, w/(m 2 · °C); α i is the modified parameter; W i is the cooling water flux density, L/(m 2 · min);

N_{R}^{i}

is the number of roll;

h_{c}^{i}

and

R_{l}^{i}

are, respectively, represent the heat transfer coefficient and the contact length between the strand and roll in W/(m 2 · °C) and m; T w , T surf , and T amb are, respectively, the cooling water temperature, the surface temperature and the ambient temperature, °C.…”

Section: Model Descriptionmentioning

confidence: 99%

Real‐Time Heat Transfer Model Based on Distributed Thermophysical Property Calculation for the Continuous Casting Process

Deng

Guan

et al. 2018

steel research int.

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In this work, a one‐dimensional real‐time heat transfer model, which considers the effect of varying thermophysical properties along slab thickness direction caused by the distribution of solute segregation, is built to predict the location of the solidification end of a wide‐thick continuous casting slab accurately. According to the measurement results of carbon segregation on the slab transverse section, a database of thermophysical properties with different carbon contents is established based on the micro‐segregation model. At the beginning of the calculation, the pre‐calculated thermophysical properties of the target slab are pre‐loaded to random access memory (RAM), and the corresponding physical parameter data are called from RAM to complete the calculation process according to the pre‐measured carbon concentration at different slab thicknesses. Additionally, the solidification relationship between the slab center and other positions along the width direction is derived based on an offline two‐dimensional heat transfer model. With calling the relationship, the whole slab uneven solidification process can be described based on the real‐time calculated results of the slab centerline solidification process. The real‐time heat transfer model is validated by measuring the slab thickness and surface temperature.

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“…17 The boundary condition of heat transfer has been described in the present authors' previous work. 1 In the mold, the heat flux decreases from the surface center to the corner due to the shrinkage of the shell. In the secondary cooling zone, the equivalent convection coefficients of each of the cooling zones were calculated according to the measured water flux distribution of the nozzles.…”

Section: Heat Transfer Modelmentioning

confidence: 99%

Thermo-Mechanical Behavior of the Continuous Casting Bloom in the Heavy Reduction Process

Zhu

2016

JOM

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A two-stage sequential heavy reduction (HR) method, in which the reduction amount was increased both before and after the solidification end, is presented to simultaneously improve the homogeneity and compactness of the continuous casting bloom. With bearing steel GCr15 chosen as the specific research steel, a three-dimensional thermal-mechanical finite element model was developed to simulate and analyze the thermal and mechanical behaviors of the continuous casting bloom during the HR process. In order to ensure the accuracy of the simulation, the constitutive model parameters were derived from the experimental results. The predicted temperature distribution and shell thickness were verified using a thermal infrared camera and nail shooting results, respectively. The real measured relationship between the HR pressure and amount were applied to verify the mechanical model. The explorative application results showed that the quality of the bloom center and compactness of rolled bars have both been significantly improved after the HR was applied.

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Analysis and Application of Soft Reduction Amount for Bloom Continuous Casting Process

Cited by 71 publications

References 26 publications

Dilatancy in semi-solid steels at high solid fraction

Dilatancy in semi-solid steels at high solid fraction

Real‐Time Heat Transfer Model Based on Distributed Thermophysical Property Calculation for the Continuous Casting Process

Thermo-Mechanical Behavior of the Continuous Casting Bloom in the Heavy Reduction Process

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