Reducing macro segregation of high carbon steel in continuous casting bloom by final electromagnetic stirring and mechanical soft reduction integrated process

An, Hanghang; Bao, Yan; Wang, Min; Zhao, Li Hua

doi:10.1051/metal/2017029

Cited by 18 publications

(12 citation statements)

References 23 publications

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“…(3) Total reduction amount The total reduction amount is related to the reduction ratio [85]. The optimized reduction amount is that which can compensate the volume shrinkage of the molten steel at the solidification end, decrease the flow of the molten steel enriched solute elements, and reduce the center segregation [86][87][88][89]. If the reduction amount is too large, it will lead to internal cracks formation, which will also adversely affect the service life of the SR equipment.…”

Section: ) Reduction Ratiomentioning

confidence: 99%

Application Status and Development Trend of Continuous Casting Reduction Technology: A Review

Nian

Zhang

et al. 2022

Processes

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Continuous casting is a dominant steelmaking process due to its steady-state nature, enhanced yield of steel production, and low consumption of energy and manpower. However, the production of defect-free cast products is still a big challenge, as the internal defects, including macro-segregation of alloying elements, cracks, and pores, can be easily formed during the solidification process, which seriously deteriorates the microstructure and mechanical properties of the cast products. Therefore, this paper puts forward the common solutions to overcome these problematic issues. The reduction technology can effectively improve the center segregation of the billet, bloom, and slab. The history of the development of the reduction technology is summarized and classified according to the variations in research trend. Furthermore, the basic principles and parameters of reduction technology are described to implement them in the actual production process. This paper compares the similarities and differences between soft reduction (SR) and heavy reduction (HR) technologies with a particular focus on the theoretical research of HR technology and further elaborates the key parameter and equipment problems during implementation of HR. Moreover, this paper also considers the HR technology adopted by Baosteel as a case study, which helped to put forward some viewpoints for the future development of reduction technology.

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Section: ) Reduction Ratiomentioning

confidence: 99%

Application Status and Development Trend of Continuous Casting Reduction Technology: A Review

Nian

Zhang

et al. 2022

Processes

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“…[20,21] The implementation of the soft reduction process needs to set a reasonable reduction interval and amount to ensure good effect. [22][23][24]…”

Section: Generation Mechanism Of Central Cracksmentioning

confidence: 99%

Formation and Control of Central Cracks in Alloy Steel ZKG223

Zhang

Bao

Zhao

et al. 2022

steel research int.

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When the molten steel contains high carbon and alloy elements, the continuous casting bloom is prone to internal defects. Soft reduction is an effectively means of improvement and is widely utilized in the continuous casting process. Herein, the generation mechanism of the central cracks in alloy steel ZKG223 is analyzed in detail; that is, the tensile stress is generated by the accelerated solidification and shrinkage in the core of the bloom at the end of solidification, which acts on the dendrites and causes central cracks. In order to reduce the shrinkage stress during the solidification of the bloom, the reasonable reduction parameters of the bloom are determined by establishing a soft reduction model, and the industrial test is carried out. Through the implementation of well‐designed soft reduction, the central cracks in the bloom are significantly bridged, and the secondary dendrite spacing in the center of the bloom is shortened from 315 to 230 μm. The maximum positive and negative carbon segregation indices in the cross section of the bloom are changed from 1.039 and 0.957 to 1.020 and 0.977, respectively, which greatly improve the uniformity of element distribution and the internal quality of the bloom.

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“…Meanwhile, a banded microstructure is also an internal defect of steel that deteriorates mechanical properties. Though the relationship between central segregation and continuous casting parameters has been reported in previous studies [12][13][14], the heredity effect of central segregation on segregated bands and mechanical properties is still a problem that has not yet been solved. A few works have been done to examine the relative influences of central segregation of billets on the banded microstructures and mechanical properties of final products.…”

Section: Introductionmentioning

confidence: 95%

“…The quality of a continuously cast billet is closely related to the continuous casting processes, such as superheating, secondary cooling [12], electromagnetic stirring [13] and soft reduction [14].…”

Section: Introductionmentioning

confidence: 99%

The Significance of Central Segregation of Continuously Cast Billet on Banded Microstructure and Mechanical Properties of Section Steel

Guo

Wang

et al. 2020

Metals

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The solidification structure and segregation of continuously cast billets produced by different continuous casting processes are investigated to elucidate their effect on segregated bands in hot-rolled section steel. It suggested that segregated spots are mainly observed in the equiaxed crystal zone of a billet. The solidification structure is directly related to superheating and the intensities of secondary cooling. To a certain extent, the ratio of the columnar crystal increases with the increase of superheating and secondary cooling. Moreover, the number of spot segregations decreases with the decrease of the equiaxed crystal ratio. After hot rolling, the segregation spots are deformed to form segregated bands in steels. The severe segregation of Mn in segregated bands corresponds with that in the segregation spots. The elongation ratio and low temperature toughness deteriorate significantly by a high fraction of degenerate pearlite caused by central segregation. With a decrease of central segregation, the total elongation is increased by 10% and the ductile–brittle transition temperature (DBTT) is also reduced from −10 to −40 °C. According to the experimental results, columnar crystal in billets is preferred to effectively reduce the degree of central segregation and further improve low temperature toughness and the elongation ratio.

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Reducing macro segregation of high carbon steel in continuous casting bloom by final electromagnetic stirring and mechanical soft reduction integrated process

Cited by 18 publications

References 23 publications

Application Status and Development Trend of Continuous Casting Reduction Technology: A Review

Application Status and Development Trend of Continuous Casting Reduction Technology: A Review

Formation and Control of Central Cracks in Alloy Steel ZKG223

The Significance of Central Segregation of Continuously Cast Billet on Banded Microstructure and Mechanical Properties of Section Steel

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