Effect of Dynamic Soft Reduction Range and Amount on Central Segregation in Bloom and the Resulting Microstructure in the Rod of GCr15‐Bearing Steel

Yao, Cheng; Wang, Min; Cheng, Ming; Lü, Xing; Wang, Ying; Gao, Yubo; Bao, Yanping

doi:10.1002/srin.202200495

Cited by 5 publications

(5 citation statements)

References 22 publications

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“…They found that the reduction amount of 2 mm and 4 mm is enough to compensate the solidification shrinkage porosity, while the size of the shrinkage cavity was significantly increased ~2 times with the increase of the reduction amount to 6 mm. Yao et al [62] studied the solid-liquid temperatures and mechanical properties of GCr15 bearing steel. According to the experimental results and heat transfer model, the reduction interval and optimized reduction amount was proposed for dynamic SR technology.…”

Section: Experimental Researchmentioning

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: Experimental Researchmentioning

confidence: 99%

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

Nian

Zhang

et al. 2022

Processes

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“…Spot segregation defects can be classified into two types: loose and speckled. [ 10,31,32 ] The speckled type spot segregation defects are larger in size and appear more in the center of the continuous casting slab, while the spot segregation defects appearing in the 3/8 thickness of the slab are basically of the loose type.…”

Section: Discussionmentioning

confidence: 99%

“…The continuous casting process has the advantage of stability and mass production compared to the electroslag remelting process. Some high-carbon content steels have been industrially produced by the continuous casting process, e.g., GCr15 (C: 1.00%, Cr: 1.50%), [7][8][9][10][11][12][13][14] 82 A, B (C: 0.82%), [15,16] Mn13 (C: 1.00%, Mn: 13.00%), [17,18] etc. The techniques such as cooling rate control, [8,12,14,16] electromagnetic stirring, [7,8,13] soft reduction, [10,11,13] casting speed control, [16,18] and low-superheat casting [12,16] have been used to improve the solidification quality of the continuous casting slab as well as to alleviate the segregation of the alloying elements.…”

Section: Introductionmentioning

confidence: 99%

“…Some high-carbon content steels have been industrially produced by the continuous casting process, e.g., GCr15 (C: 1.00%, Cr: 1.50%), [7][8][9][10][11][12][13][14] 82 A, B (C: 0.82%), [15,16] Mn13 (C: 1.00%, Mn: 13.00%), [17,18] etc. The techniques such as cooling rate control, [8,12,14,16] electromagnetic stirring, [7,8,13] soft reduction, [10,11,13] casting speed control, [16,18] and low-superheat casting [12,16] have been used to improve the solidification quality of the continuous casting slab as well as to alleviate the segregation of the alloying elements. However, the central segregation of C elements still exists and carbides will precipitate in the regions where the segregation of alloying elements is severe.…”

Section: Introductionmentioning

confidence: 99%

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Precipitation, Growth, and Aggregation Behavior of Primary Carbides during Continuous Casting of 6Cr13 Slabs

Li,

Pan

et al. 2024

steel research int.

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The types, distribution, morphology, orientation, growth, and aggregation mechanism of primary carbides in the continuous casting slab of 6Cr13 high‐carbon martensitic stainless steel are investigated. In the results, it is shown that M7C3 carbides precipitate from the liquid steel at the end of solidification. The area fraction of primary carbides in the slab thickness direction shows an overall decreasing trend from the center to the edge. And, the closer to the center region, the greater the difference in carbide distribution due to the presence of spot segregation defects. At 1/8 thickness and edges in the slab, the fast cooling rate and fine dendrites make the carbide morphology to be a small‐sized brain like that aggregates a large number of spherical carbides. At 1/4 thickness in the slab, blocky, fibrous, and spherical carbides precipitate successively and eventually aggregate together. At 3/8 thickness and center in the slab, the cooling rate is slower and spot segregation defects are randomly distributed in this region. The carbide morphology is mostly small‐sized brain like in the non‐spot segregation region. However, the alloying elements are highly supersaturated and the carbides can grow sufficiently to form less oriented, large‐sized brain‐like carbide in the spot segregation region.

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“…Due to solute redistribution and forced cooling, the heterogeneous defects, such as macrosegregation and shrinkage cavity, are inevitable in continuous casting and are difficult to eliminate through subsequent processes, which seriously affect the quality of steel products. [1,2] Hence, a variety of technologies have been developed to improve the homogeneity of casting blooms, such as electromagnetic swirling flow, [3,4] electromagnetic stirring, [5][6][7] soft or heavy reduction, [8][9][10][11] and so on. The pulsed electromagnetic field, with advantages such as low energy consumption, convenient application, and significant effects, has become a research hotspot in the field of solidification structure refinement technology.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Process Parameters for 40Cr Steel Continuous Casting Round Bloom with Pulsed Magneto‐Oscillation Treatment

Yang,

Chen,

Zhang

et al. 2024

steel research int.

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To reduce the solidification structure defects and the macrosegregation of the Φ300 mm continuous casting round bloom, the pulsed magneto‐oscillation (PMO) treatment is added at the secondary cooling zone. A numerical model for calculating the pulsed electromagnetic field, flow field, and temperature field in continuous casting is established, and the coupling simulations of multiphysical fields under different casting parameters and PMO parameters are performed. Their influence on solidification process and the appropriate parameters are discussed. The industrial experiments conducted under the recommended parameters yield good results. Industrial experiments show that when the peak current is increased from 1350 to 1550 KIA and the casting speed is increased from 0.75 to 0.90 m min−1, PMO can increase the equiaxed grain zone and reduce the carbon macrosegregation of the bloom. Moreover, at high casting speed, PMO treatment can significantly promote columnar‐to‐equiaxed transition and increase the width of mixed grain zone.

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Effect of Dynamic Soft Reduction Range and Amount on Central Segregation in Bloom and the Resulting Microstructure in the Rod of GCr15‐Bearing Steel

Abstract: The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/srin.202200495.

Cited by 5 publications

References 22 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

Precipitation, Growth, and Aggregation Behavior of Primary Carbides during Continuous Casting of 6Cr13 Slabs

Optimization of Process Parameters for 40Cr Steel Continuous Casting Round Bloom with Pulsed Magneto‐Oscillation Treatment

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