Surface Defect Formation in Steel Continuous Casting

2018 ◽  
Vol 941 ◽  
pp. 112-117 ◽  
Author(s):  
Matthew L.S. Zappulla ◽  
Brian G. Thomas
Keyword(s):  
Continuous Casting ◽  
Thermal Model ◽  
Defect Formation ◽  
Casting Process ◽  
Element Model ◽  
Steel Shell ◽  
Formation Mechanisms ◽  
Δ Ferrite ◽  
And Behavior ◽  
Longitudinal Cracks

Serious defects in the continuous casting of steel, including surface cracks and depressions, are often related to thermal mechanical behavior during solidification in the mold. A finite-element model has been developed to simulate the temperature, shape, and stress of the steel shell, as it moves down the mold in a state of generalized plane strain at the casting speed. The thermal model simulates transient heat transfer in the solidifying steel and between the shell and mold wall. The thermal model is coupled with a stress model that features temperature-, composition-, and phase dependent elastic-visco-plastic constitutive behavior of the steel, accounting for liquid, δ-ferrite, and γ-austenite behavior. Depressions are predicted to form when the shell is subjected to either excessive compression or tension, but the shapes, severity, and appearance differ with conditions. Cracks appearing without depressions are suggested to form in the lower ductility trough when the shell is colder but more brittle. The local thickness of the shell and austenite layer appears to have major effects as well. The model reveals new insights into the formation mechanisms and behavior of surface depressions and longitudinal cracks in the continuous casting process.

3D Fem Study of Fluid Flow in the Mould for Billet Continuous Casting

2009 ◽  
Vol 79-82 ◽  
pp. 1269-1272
Author(s):  
Wei Chen ◽  
Bao Xiang Wang ◽  
Yu Zhu Zhang ◽  
Jin Hong Ma ◽  
Su Juan Yuan
Keyword(s):  
Fluid Flow ◽  
Continuous Casting ◽  
Casting Speed ◽  
Three Dimensional ◽  
Casting Process ◽  
Element Model ◽  
3D Fem ◽  
Billet Continuous Casting ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

In this paper, a three-dimensional finite element model is developed to simulate and analyze the turbulent flow in the mould of billet continuous casting. The result shows that if the SEN is used in the continuous casting process, there exists a symmetrical stronger vortex in the middle of the mould and a weaker vortex above the nozzle. The casting speed, the depth and diameter of SEN all have significant effect on the fluid flow field and the turbulent kinetic energy on the meniscus, and then have effect on the billet quality. At the given conditions, the optimum set of parameters is: the casting speed 0.035 , the depth of the SEN 0.1 , the diameter of the SEN 0.025 . Online verifying of this model has been developed, which can be proved that it is very useful to control the steel quality and improve the productivity.

Numerical Calculation About Influence of Crystallizer Structure on the Stress Evolution Process of Horizontal Continuous Casting of Copper Tubes

2021 ◽  
Author(s):  
Yao Xiao ◽  
Yi Han ◽  
Ming Huang ◽  
Xin-Liang Gao ◽  
Jia-Yin Liu
Keyword(s):  
Continuous Casting ◽  
Equivalent Stress ◽  
Semimajor Axis ◽  
Casting Process ◽  
Element Model ◽  
Cooling Zone ◽  
Continuous Casting Process ◽  
Horizontal Continuous Casting ◽  
Temperature Field Model ◽  
Measurement Experiment

Abstract The horizontal continuous casting plays a key role in the production of inner grooved copper tubes. In order to improve the accuracy of the temperature field model of the copper tubes horizontal continuous casting process, the model heat transfer coefficient was validated through temperature measurement experiment of graphite crystallizer. The finite element model of stress field evolution was established, based on considering the temperature and microstructure changes. It was found that tensile stress was generated in the outer layer of the casting billet and compressive stress was generated in the inner layer, when the casting billet entered the primary cooling zone. The paper investigated the mechanism of the liquid inlet number and shape on the microstructure and stress distribution after the casting billet was solidified. When the number of liquid inlets was 6, the ratio of the semimajor axis of ellipsoid to the short semi-axis was 3:2 and the backward tilt angle was 10°, the equivalent stress value of the casting billet was smaller and the grains were dense and uniform. This paper promotes the research of horizontal continuous casting process and provides measurable reference for improving the quality of casting billet in the further.

scholarly journals Effect of Bubbles on Crystallization Behavior of CaO–SiO2 Based Slags

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 193 ◽  
Author(s):  
Shaopeng Gu ◽  
Guanghua Wen ◽  
Zequan Ding ◽  
Junli Guo ◽  
Ping Tang ◽  
...  
Keyword(s):  
Molten Slag ◽  
Casting Process ◽  
Steel Shell ◽  
Slag Film ◽  
Peritectic Steel ◽  
Activation Energy Of Crystallization ◽  
Mold Fluxes ◽  
Temperature Transformation ◽  
Longitudinal Cracks ◽  
Cct Diagrams

Surface longitudinal cracks are a serious problem and particularly prevalent in the casting of peritectic steel (carbon content between 0.10%C and 0.18%C, non-alloyed). It is usually alleviated by controlling the horizontal heat transfer from the steel shell to the mold through increasing the crystallization performance of slags. In the actual continuous casting process, a large number of bubbles are formed in the molten slags, and the crystallization properties of the mold fluxes are affected by bubbles. Therefore, an investigation of the influence of bubbles on the crystallization performance of mold fluxes was carried out by applying the hot thermocouple technique and it is hoped that surface longitudinal cracks can be solved in this way in the peritectic steel casting process. The continuous cooling transformation (CCT) diagrams and time–temperature transformation (TTT) diagrams were constructed for an analysis of the crystallization kinetics. The results showed that the crystallization ability of mold fluxes was enhanced by adding bubbles through shortening the incubation time of crystallization, increasing the critical cooling rate, and decreasing the activation energy of crystallization. As a result, the crystalline fraction, slag film thickness, and surface roughness of the slag films were improved, but the crystalline phase was not affected by bubbles. With an increase of the bubble content remaining in the molten slag, the growth mechanism of the cuspidine crystal phase changed from a low dimension to a high dimension, and the content of the molten slag’s structure unit (Q1) needed for cuspidine in the molten slag was markedly increased.

Defect Formation Mechanism and Influence of Processing Parameters on Surface Quality of Copper Clad Steel Composite Wires Prepared by Core-Cladding Continuous Casting

2017 ◽  
Vol 898 ◽  
pp. 1183-1189
Author(s):  
Wei Yu Wu ◽  
Xue Feng Liu ◽  
Feng Yi
Keyword(s):  
Continuous Casting ◽  
Surface Quality ◽  
Molten Metal ◽  
Surface Defects ◽  
Defect Formation ◽  
Formation Mechanisms ◽  
Core Diameter ◽  
Melt Temperature ◽  
Clad Steel ◽  
Composite Wires

Copper clad steel (CCS) composite wires with the carbon steel core diameter of 8 mm and copper cladding thickness of 1 mm were prepared by core-cladding continuous casting method under argon protection. The effects of melt temperature, molten metal height and drawing velocity on the surface quality were investigated. The formation mechanisms of the surface defects were discussed. The results showed that CCS wires with good surface quality could be continuously fabricated at a melt temperature of 1120 to 1200°C, a molten metal height of 2 to 4 cm and a drawing velocity of 10 to 30 mm/min. Raising the melt temperature, increasing the molten metal height or decreasing the drawing velocity is in favor of improvements in the surface quality. Insufficient supplement of liquid copper during solidification shrinkage resulted in surface dimple. Transverse hot cracking and exposed steel defect appeared because the frictional force between cladding metal and mold was larger than the tensile strength of cladding metal under high temperature.

Continuous Casting of Magnesium Alloy Billet Using Electromagnetic Techniques

2010 ◽  
Vol 654-656 ◽  
pp. 787-790
Author(s):  
Myoung Gyun Kim ◽  
Jong Ho Kim ◽  
Joon Pyo Park ◽  
Gyu Chang Lee ◽  
Woo Jin Kim
Keyword(s):  
Continuous Casting ◽  
Latent Heat ◽  
Defect Formation ◽  
Casting Process ◽  
Heat Of Fusion ◽  
High Quality ◽  
Homogeneous Microstructure ◽  
Latent Heat Of Fusion ◽  
Quality Surface ◽  
High Quality Surface

Currently, magnesium billets produced by ingot casting or direct chill casting process, result in low-quality surfaces and peer productivity. Continuous casting technology for high-quality surface billets with fine-grained and homogeneous microstructure can be a solution for the cost barrier breakthrough. The latent heat of fusion per weight (J/g) of magnesium is similar to that of other metals, however, considering the heat emitted to the mould surface during continuous casting in meniscus region and converting it to the latent heat of fusion per volume, magnesium will be rapidly solidified in the mould during continuous casting, which induces subsequent surface defect formation. In this study, electromagnetic casting and stirring (EMC and EMS) techniques are proposed to control solidification process conveniently by compensating the low latent heat of solidification by volume and to fabricate magnesium billets with a high quality surface.

Effects of Magnetic Field on the As-Cast Structures of Dual-Ingot Low Frequency Electromagnetic Semi-Continuous Casting

2010 ◽  
Vol 97-101 ◽  
pp. 1033-1036
Author(s):  
Gao Song Wang ◽  
Zhi Hao Zhao ◽  
Jian Zhong Cui ◽  
Shuai Dong
Keyword(s):  
Magnetic Field ◽  
Continuous Casting ◽  
Three Dimensional ◽  
Low Frequency ◽  
Casting Process ◽  
Element Model ◽  
Magnetic Flux Density ◽  
Continuous Casting Process ◽  
Continuous Casting Mould ◽  
Three Dimensional Finite Element

Based on the non-uniform distribution of magnetic field within the ingot caused by its interactions during the dual-ingot low-frequency electromagnetic semi-continuous casting process, a three-dimensional finite element model was constructed. This model was meshed and calculated with the ANSYS software, and the distribution of magnetic field in low-frequency semi-continuous casting mould was obtained. The influence of the distance and current directions between two coils on magnetic field distribution in the ingot was studied. Calculated results showed that, during dual-ingot low-frequency electromagnetic semi-continuous casting process, whether the current was in the same direction or the reverse, magnetic field density on the remote end should be greater than that on the proximal of the same ingot; when the current directions of nearby coils were reverse, the magnetic intensity on ingot was higher than that with the same directions; as the distance between coils increased, the distal and proximal difference of magnetic flux density declined. Based on the results, a casting mould for dual-ingot electromagnetic semi-continuous casting ø152mm 7075 aluminum alloy was designed and produced. The experimental results showed that when the current directions of nearby coils were reverse, the as-cast macrostructures were a little bit better than that with the same directions. Moreover, when the current directions were reverse, the heterogeneity of the as-cast inner structure could be almost ignored.

scholarly journals Thermal Analysis of Solidifying Steel Shell in Continuous Casting Process

2020 ◽  
Vol 47 ◽  
pp. 686-692
Author(s):  
Hoang Son Tran ◽  
Etienne Castiaux ◽  
Anne-Marie Habraken
Keyword(s):  
Thermal Analysis ◽  
Continuous Casting ◽  
Casting Process ◽  
Steel Shell ◽  
Continuous Casting Process

The Air Reoxidation and the Formation of Large Inclusions in Continuous Casting Process

1973 ◽  
Vol 59 (1) ◽  
pp. 72-84 ◽  
Author(s):  
Kichinosuke MATSUNAGA ◽  
Chikakazu NAMIKI ◽  
Taiji ARAKI
Keyword(s):  
Continuous Casting ◽  
Casting Process ◽  
Continuous Casting Process
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