Macrostructure of and Segregation in Continuously Cast Carbon Steel Billets

Mori, Hisashi; Tanaka, N.; Satô, Norio; Hirai, Masazumi

doi:10.2355/isijinternational1966.12.102

Cited by 19 publications

(9 citation statements)

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“…5-8 reveals only a columnar crystal zone for all the heat samples. Figure 5 shows first group sample (heat 2), with large single 'V' segregates with discontinuous mini-ingotism 31 and discontinuous filled interdendritic cracks in the upper and bottom areas. The distance between 'V' segregates changes from 12 to 15 mm as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Spray cooling pattern and microthermomechanical rigidity criterion for improving inner quality in continuously cast steel slabs

El-Bealy

2013

Ironmaking & Steelmaking

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A new concept has been developed to assess, and a new technique developed to improve, the microthermomechanical rigidity of the solidifying shell in the secondary cooling zones during continuous casting of steel. This is to maximise the coherent solid shell resistance 'I c ' against thermometallurgical and mechanical stresses at different levels from meniscus. The idea behind this concept is to optimise the degree of homogeneity of the cooling pattern between a pair of rolls. The effect of the degree of homogeneity of the cooling pattern between a pair of rolls 'HDCP', in different spray cooling zones on the different types of centreline segregates has been investigated. A number of plant trials with two different water cooling patterns between a pair of rolls have been performed. The metallographic investigation contains examinations and measurements of the level of centreline segregates of collected samples. A one dimensional (1D) transient finite difference mathematical model of thermal, solidification, solid shell resistance and cooling conditions has been developed to test the different effects of spray patterns on the microthermomechanical rigidity concept and therefore on the mechanism of centreline macrosegregation level. The results indicate that the increase in the degree of homogeneity of the cooling conditions is proportional to the increase in slab internal microquality. The results show that the degree of homogeneity of the cooling pattern affects centreline macrosegregation significantly. This depends significantly on the degree of homogeneity of cooling pattern between a pair of rolls, its location from the meniscus and, generally, on the increase microthermomechanical rigidity concept.

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Section: Resultsmentioning

confidence: 99%

Spray cooling pattern and microthermomechanical rigidity criterion for improving inner quality in continuously cast steel slabs

El-Bealy

2013

Ironmaking & Steelmaking

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“…This agrees well with the measurements and predications of bulging level by Miyazawa and Schwerdtfeger, 60 where they concluded that the major cause of centreline macrosegregation is solid shell bulging. In addition to the bulging shape, several operational factors have been reported to increase the severity of centreline segregation such as steel composition, 61 structure crystal, 62 casting speed, 63 tundish superheat, 64 section size, 65 EMS 45 and, finally, the characteristics of mechanical soft reduction technique. 18 These factors affect the central quality of steel slabs by different segregation levels.…”

Section: Centreline Zonementioning

confidence: 99%

New macrosegregation criteria for quality problems in continuous casting of steel

El-Bealy

2013

Ironmaking & Steelmaking

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To estimate the quality condition in continuously cast steel slabs, simple but accurate macrosegregation criteria have been proposed. The formation of macrosegregation phenomena in continuous casting of peritectic carbon steels has been investigated by metallographic study of collected slab samples. The metallographic study involved plant trails to collect the slab samples and to prepare them for chemical macrosegregation analysis. The experimental results show a fluctuation of carbon between positive and negative segregation with distance from slab surface based on the cooling conditions experienced by the slab. Via mathematical analysis, formulae of average macrosegregation level ASL, its fluctuation level FSL and its segregation quality number SQN have been developed. The results calculated by these formulae show good agreement with the description of the formation mechanisms of different continuous casting defects and their locations. Therefore, these calculations illustrated that macrosegregation criteria and their distributions can be considered by experimental, simple and vital tools to evaluate the conditions of surface and inner qualities in continuously cast steel slabs. The mechanisms of these criteria with some mechanisms of continuous casting defects have been explained and discussed.

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“…Wyższymi współczynnikami wzbogacenia w pierwiastki stopowe i domieszkowe niż segregacja międzydendrytyczna, charakteryzuje się makrosegregacja [41]. Makrosegregacja środkowa i nieosiowe segregacje o wielkości pośredniej, do których należy segregacja typu "V", wykazują istotną różnicą w stosunku do segregacji międzydendrytycznej, którą jest wzbogacenie w węgiel strefy makrosegregacji [70][71][72]. Segregacja węgla nie występuje (lub występuje w bardzo niewielkim stopniu) w obszarach międzydendrytycznych, ze względu na wyrównywanie się stężenia węgla pomiędzy obszarami ramion dendrytów i przestrzeni międzydendrytycznych.…”

Section: Ewolucja Struktury Wlewków Ciągłych Ze Stali Niestopowych I Niskostopowych W Trakcie Przeróbki Plastycznej Na Gorącounclassified

Structure of Continuously Cast Ingots of Unalloyed and Low Alloy Steels and Its Evolution as a Result of Hot Working

Garbarz¹,

Staszica²

2018

PIMZ

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W artykule przedstawiono systematykę morfologiczną struktur powstających we wlewkach ciągłych ze stali niestopowych i niskostopowych. Scharakteryzowano pierwotną strukturę krzepnięcia (strukturę dendrytyczną) oraz ziarnową strukturę austenitu pierwotnego. W zależności od składu chemicznego stali, warunków krzepnięcia i stygnięcia wlewka ciągłego oraz od zastosowanych metod ujawniania elementów morfologicznych, jedna z tych struktur może być dominująca lub ich obrazy mogą się nakładać. Wykazano, że po początkowym okresie wzrostu fazy austenitycznej w korelacji ze strukturą dendrytyczną, w stadium rozrostu ziarna pierwotnego austenitu tracą związek z dendrytyczną strukturą krzepnięcia. Opisano cztery główne typy struktur wlewków ciągłych, powstające w wyniku przemian fazowych i strukturalnych poniżej zakresu perytektycznego, w zakresie podperytektycznym, w zakresie nadperytektycznym oraz powyżej zakresu perytektycznego. Przeanalizowano potencjalne oddziaływania dendrytycznej struktury krzepnięcia i struktury ziarnowej austenitu pierwotnego na jakość wlewka ciągłego i wyrobów stalowych, w szczególności przedstawiono wpływ segregacji międzydendrytycznej na powstawanie pasmowości mikrostrukturalnej w wyrobach stalowych.

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Macrostructure of and Segregation in Continuously Cast Carbon Steel Billets

Cited by 19 publications

References 0 publications

Spray cooling pattern and microthermomechanical rigidity criterion for improving inner quality in continuously cast steel slabs

Spray cooling pattern and microthermomechanical rigidity criterion for improving inner quality in continuously cast steel slabs

New macrosegregation criteria for quality problems in continuous casting of steel

Structure of Continuously Cast Ingots of Unalloyed and Low Alloy Steels and Its Evolution as a Result of Hot Working

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