Solidification of iron-base alloys

Fredriksson, Hasse; Stjerndahl, J.

doi:10.1179/030634582790427136

Cited by 80 publications

(44 citation statements)

References 7 publications

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“…Figure 4 shows that the critical strain, using the above method, is sharply decreased from 5.3 to 2.2 % with increases of Ni content from 0.021 to 3.35 % and slowly decreased thereafter. Austenite phases formed during solidification cause larger microsegregation 12,13) due to much lower diffusivities of solute elements in Austenite phases than in Delta ferrite phases. The sharp decrease in critical strain up to ϳ3.5 % Ni may correspond to the fact that residence time during solidification within Delta ferrite phase decreases with increases in Ni content and according to the Fe-Ni phase diagram, the Austenite phase starts to form from Ͼϳ4.1 % Ni.…”

Section: Methodsmentioning

confidence: 99%

Hot Cracking Behavior of Fe-Ni Alloys via Direct Observation.

Lee

2003

ISIJ International

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Hot cracking behavior of Fe-Ni alloys was investigated by using a high-speed camera to observe hot cracking in samples that were temperature-gradient heated and tensile deformed. The susceptibility to hot cracking was reliably evaluated based on critical strain and crack propagation length as functions of Ni content and cool side temperature. Grain size and shape in the brittle temperature region depended on liquid boundary migration due to solute diffusion within the liquid boundary under temperature gradient. High susceptibility to hot cracking of Fe-Ni alloys could be explained by the high sulfur segregation near the grain boundary and the large grain size within the solid/liquid coexisting region due to the rapid migration of the liquid boundary.KEY WORDS: hot cracking; continuous casting; Fe-Ni alloys; grain growth; sulfur segregation; direct observation of hot cracking; temperature-gradient tensile test. ent direction, and examined metallographically. Samples with hot cracks were dipped in liquid nitrogen and fractured by impact to reveal the crack surface. Auger analysis was performed in a Physical Electronics Phi 600 Auger microprobe by slicing off the measured surfaces at a rate of 0.217 nm/s to investigate the microsegregation near the crack surface. Experimental Results Evaluation of Crack SusceptibilityFigure 2 shows hot crack occurrence followed by melt flowing into the crack near the hot surface during tensile deformation. Only a portion of the specimen's width is shown due to the cover that prevents heat loss. In order to evaluate critical strain for hot cracking, it is necessary to know the length of the uniform deformation zone, the exact time deformation started and the time the crack occurred. Figure 3 shows the measured displacements of various positions within the deformation zone using a program that allows tracking a movement in any position during hot deformation. From this result and the fact that only the upper jig in the tester moves up during the tensile test, the length of the uniform deformation zone could be defined by roughly ISIJ International, Vol. 43 (2003) assuming the curve of displacements and the relative positions of the measured points to be linear. The times of initial deformation and crack occurrence could also be determined through tracking the movements of points within the deformation zone. Figure 4 shows that the critical strain, using the above method, is sharply decreased from 5.3 to 2.2 % with increases of Ni content from 0.021 to 3.35 % and slowly decreased thereafter. Austenite phases formed during solidification cause larger microsegregation 12,13) due to much lower diffusivities of solute elements in Austenite phases than in Delta ferrite phases. The sharp decrease in critical strain up to ϳ3.5 % Ni may correspond to the fact that residence time during solidification within Delta ferrite phase decreases with increases in Ni content and according to the Fe-Ni phase diagram, the Austenite phase starts to form from Ͼϳ4.1 % Ni. Figure 5 shows that critical str...

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Section: Methodsmentioning

confidence: 99%

Hot Cracking Behavior of Fe-Ni Alloys via Direct Observation.

Lee

2003

ISIJ International

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“…For the Fe-C binary alloy, the relationships between peritectic temperature range and initial carbon content were calculated and the results compared with the ones of a model reported by Fredriksson et al 25) As the calculated conditions, l 1 ϭ250 mm, Dxϭ2.5 mm and R c ϭ0.1, 0.5, 1.0, 5.0 K/s were used. Figure 6 shows the relationship between peritectic temperature range, DT p , and the initial carbon content, C 0,C , at Fe-C binary alloys.…”

Section: Peritectic Transformation Of Fe-c and Fe-c-mnmentioning

confidence: 99%

Numerical Modeling of Microsegregation for Fe-base Multicomponent Alloys with Peritectic Transformation Coupled with Thermodynamic Calculations

2010

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“…ing solid phase transformation or during peritectic reactions [9,10]. Also, Miyazawa and Schwerdtferger [11] proposed an approach to model the resistance of coherent solid shell against the thermo-mechanical stresses subjected to slab as shown in Figures 3(a) and (b).…”

Section: Introductionmentioning

confidence: 99%

“…The same approach developed by Rogberg [8], for calculating delta phase of different carbon steel alloys whereas Fredriksson and Stjerndahl [9], approach was used to calculate the different interdendritic liquid and dendritic solid phases dur- …”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mold Thermo-Mechanical Rigidity Criterion for Surface Quality of Continuous Casting of Steel

El-Bealy¹

2013

MSA

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A theoretical investigation of heat flow, solidification and solid shell resistance "I c " has been undertaken by using a mathematical model and previous plant trials. The ultimate purpose is to develop operating conditions and therefore to improve the surface quality for continuously cast steel slabs. A new simple criterion called mold thermo-mechanical rigidity "MTMR" has been proposed to evaluate and to improve these purposes. The parameters of MTMR and its non-dimensional number which use to control the surface defects are present in this investigation. Previous plant trails of slab surface defects formation have been investigated thermo-mechanically with this criterion. The predications show that this criterion is very sensitive of operating parameters and is a significant qualitative tool to evaluate the surface quality. From examination of the behavior of MTMR, the susceptibility and mechanism of surface defects formations with MTMR have been primarily discussed.

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Solidification of iron-base alloys

Cited by 80 publications

References 7 publications

Hot Cracking Behavior of Fe-Ni Alloys via Direct Observation.

Hot Cracking Behavior of Fe-Ni Alloys via Direct Observation.

Numerical Modeling of Microsegregation for Fe-base Multicomponent Alloys with Peritectic Transformation Coupled with Thermodynamic Calculations

Mold Thermo-Mechanical Rigidity Criterion for Surface Quality of Continuous Casting of Steel

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