Spatial Characterization of Internal Defects in Medium Carbon Steel via X‐Ray Computed Tomography

Ali, Naqash; Zhang, Liqiang; Sui, Zhisong; Zhou, Hongwei; Zhang, Chaojie; Nian, Yi

doi:10.1002/srin.202100777

Cited by 4 publications

(3 citation statements)

References 31 publications

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“…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. The increasing reduction amount was always accompanied with a high stress concentration at the two-phase zone, which is mainly responsible for the cracks initiation which further propagate from the stress concentrated toward the stress-free area [90]. If the reduction amount is too small, the effect of SR will not be obvious, as the effective reduction will not shift to the core of cast product.…”

Section: ) Reduction Ratiomentioning

confidence: 99%

“…Cheng et al [92] compared the influence of different number of reduction rolls on the internal porosity of the slab by using single and multiple rolls to enhance the efficiency of SR technology. Currently, several researchers focused on the exploration of reduction process parameters and the adjustment of equipment related to reduction technology to implement the optimized parameters in the actual production process [51,56,90]. For example [93], the control of cooling water intensity and casting speed in the secondary cooling zone can accurately determine the reduction interval.…”

Section: Research On Reduction Equipmentmentioning

confidence: 99%

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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%

Section: Research On Reduction Equipmentmentioning

confidence: 99%

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

Nian

Zhang

et al. 2022

Processes

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“…Reasonable undercutting of the big billet at the end of the solidification can compensate for the solidification shrinkage in the paste zone, effectively reducing center loosening and center segregation within the cast billet. It should be noted that the two-phase region of medium and high carbon steel is wider, making it more susceptible to defects such as center segregation, shrinkage, and porosity [17,18]. However, when dealing with large cross-section blooms, center mass defects are more likely to occur, requiring a larger reduction to compensate for solidification shrinkage.…”

Section: Introductionmentioning

confidence: 99%

Homogenization Path Based on 250 mm × 280 mm Bloom under Mixed Light and Heavy Presses: Simulation and Industrial Studies

Dang,

Wang,

Wang

et al. 2024

Metals

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This study proposed a new method for homogenizing continuous casting blooms based on solidification simulation calculations and industrial tests. The text describes a theoretical analysis of the solidification route of a cast billet of high-carbon alloy steel (B300A) under different process conditions. It summarizes the changing law of different under-pressure process parameters and under-pressure efficiency. The text also presents a solution to the seriousness of center shrinkage defects in the continuous casting of a large square billet of high-carbon alloy steel with the synergistic control technology of mixed light and heavy mixing under pressure. The study indicates that the center carbon segregation index of a high carbon steel continuous casting billet is 1.05, with a carbon extreme difference of not more than 0.08% and a proportion of 98.4%. Additionally, the center shrinkage is not more than a 0.5 level with a proportion of 99.5%. Meanwhile, the internal quality of cast billets has been improved, allowing for the rolling of large-size bars with a low consolidation ratio. The pass rate for internal ultrasonic flaw detection using the GB/T4162A grade is now higher than 99.95%, significantly reducing process costs and improving production efficiency for continuous casting and rolling.

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Research on the source of internal fault defects in 40Mn2 oil drill pipe

Gao,

Bao,

Xing

et al. 2024

Metall. Res. Technol.

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As an essential material in various industries, steel’s internal defects can seriously affect its performance and cause huge economic losses. To investigate the source of internal fault defects in oil drill pipes, this study used ultrasonic testing equipment to accurately locate internal fault defects in steel, and obtained the spatial coordinates of the defects as (2.15, 2.29, 0.77). Then, by dissecting layer by layer, the target defect was determined to be a large Al2O3 inclusion with a length of 1.609 mm and a width of 0.2 mm. Afterwards, based on the results of automatic scanning of inclusions, this study used extreme value statistical method to estimate the maximum size inclusions that may exist in steel, and found that the target defect size was much larger than the estimated value. Finally, to further determine the source of large inclusions, this study conducted sampling and analysis on immersion nozzles, refining slag, tundish slag, and mold flux. The study found that the matching degree between the composition of large inclusions and the composition of submerged nozzle nodules was the highest, indicating that the fault defect was caused by the peeling of nozzle nodules. This indicates the direction for process optimization.

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Spatial Characterization of Internal Defects in Medium Carbon Steel via X‐Ray Computed Tomography

Cited by 4 publications

References 31 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

Homogenization Path Based on 250 mm × 280 mm Bloom under Mixed Light and Heavy Presses: Simulation and Industrial Studies

Research on the source of internal fault defects in 40Mn2 oil drill pipe

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