Internal Stresses in Iron and Steel

Andrews, T

doi:10.1038/061541b0

Cited by 73 publications

(107 citation statements)

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“…Ae 3 temperatures (austenite to ferrite transformation temperature under equilibrium conditions) were calculated using Andrew's formula 8) and have a value of 802°C and 811°C for the as-cast and the as-rolled steels respectively. Ar 3 temperature (austenite to ferrite transformation temperature in continuous cooling conditions) was calculated using the formula of Ouchi 9) and has a value of 733°C for the as-cast steel and 713°C for the as-rolled one.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…Under these circumstances, the embrittlement caused by the existence of a ferrite layer would be extended to higher temperatures than the ones initially calculated. According to the equations used to calculate Ae 3 and Ar 3 , 8,9) most alloying additions decrease these transformation temperatures and only Si and Mo would increase them. Therefore, and increase of Ae 3 related to segregation is not likely to be taking place since neither Si nor Mo have tendency to segregate.…”

Section: Overview Of the Mechanisms Of Hot Ductilitymentioning

confidence: 99%

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Evaluation of the Hot Ductility of a C–Mn Steel Produced from Scrap Recycling

Calvo¹,

Cabrera²,

Ahmad

et al. 2007

ISIJ Int.

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The use of scrap for the production of steel has been related to a high incidence of transverse cracking during continuous casting. This phenomenon is linked to the high contents on residual elements and impurities present in recycled steels. In order to understand the embrittlement mechanisms that can take place at high temperatures, the hot ductility of a C-Mn steel with residual contents of Cu and Sn was analyzed. The steel was evaluated in two as-received conditions, i.e. as-cast and as-rolled, and samples were subjected to different reheating and in-situ melting cycles prior to tensile tests. Testing temperatures ranged from 650 to 1 100°C and strain rate was 5 · 10 Ϫ3 s Ϫ1. Results show that the width and depth of ductility troughs depend on both the reheating cycle and the as-received condition of the material. According to the fractographical analysis, a reheating of the samples at 1 100°C leads to a combined intergranular and interdendritic fracture while samples reheated at 1 330°C exhibit mainly intergranular features at temperatures in the ductility trough. The interdendritic brittleness for samples reheated at the low temperature is related to the microsegretation taking place during solidification as it can be demonstrated with samples in-situ melted. On the other hand, intergranular brittleness is related to the segregation of impurities and residuals to grain boundaries. The recovery of the ductility in the high temperature range is associated to the appearance of D-REX. The differences observed between the as-cast and as-rolled as-received condition of the steel are associated to differences in the austenite grain size and its effect on dynamic recrystallization.

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Section: Experimental Methodsmentioning

confidence: 99%

Section: Overview Of the Mechanisms Of Hot Ductilitymentioning

confidence: 99%

Evaluation of the Hot Ductility of a C–Mn Steel Produced from Scrap Recycling

Calvo¹,

Cabrera²,

Ahmad

et al. 2007

ISIJ Int.

View full text Add to dashboard Cite

show abstract

“…4, and one can see that the average carbon concentration increases from about 0.94 to 1.06 % during the designed tensile test. From a thermodynamic point of view, this composition change means that there is only about 50 K decrease of the M S temperature 27) or about 300 J/mol decrease of the chemical driving force. 4) Therefore, the XRD measurements show a small carbon concentration variation in the retained austenite.…”

Section: Mechanical Stability Measured By Conventionalmentioning

confidence: 99%

“…The transition temperature of individual austenite grain with different carbon concentration (C%), M S temperature, can be calculated using Andrews' empirical equation: 27) M S ϭ766Ϫ425ϫC% (in K) ..................... (4) where the constant 766 is calculated considering the alloying elements re-distribution during intercritical annealing. 23) The calculated C%-M S relation is plotted in Fig.…”

Section: Thermal Stability By Magnetization Measurementsmentioning

confidence: 99%

Thermal and Mechanical Stability of Retained Austenite in Aluminum-containing Multiphase TRIP Steels.

et al. 2002

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Stability of retained austenite is the key issue to understand transformation-induced plasticity (TRIP) effect. In this work, both thermal stability and mechanical stability are investigated by thermo-magnetic as well as in situ conventional X-ray diffraction and micro synchrotron radiation diffraction measurements. The thermal stability in a 0.20C-1.52Mn-0.25Si-0.96Al (wt%) TRIP steel is studied in the temperature range between 5 and 300 K under a constant magnetic field of 5 T. It is found that almost all austenite transforms thermally to martensite upon cooling to 5 K and M S and M f temperatures are analyzed to be 355 and 115 K. Transformation kinetics on the fraction versus temperature relation are well described by a model based on thermodynamics. From the in situ conventional X-ray and synchrotron diffraction measurements in a 0.17C-1.46Mn-0.26Si-1.81Al (wt%) steel, the volume fraction of retained austenite is found to decrease as the strain increases according to Ludwigson and Berger relation. The diffraction measurements also show that the mechanical stability depends on the orientation of the grain with respect to the direction of the applied stress, and the austenite grains at an angle of 45°or 60°were found to be more stable than those at lower or higher angles. Both thermal and diffraction experiments show an increase in the average carbon concentration of the remaining austenite with lowering temperature or increasing stress. Thermal and mechanical stability of retained austenite is therefore attributed to the carbon distribution over different austenite grains.

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“…As occurs in the case of the B s calculation, there are some empirical formulas for M s as a function of the chemical composition 14,[18][19][20][21][22][23] with different grades of accuracy depending on the allowed range of alloying elements. An alternative approach is to use thermodynamic theory, which has the advantage that any solute combination can be considered on condition that the thermodynamic data are available.…”

Section: Introductionmentioning

confidence: 99%

Time-Temperature-Transformation Diagram within the Bainitic Temperature Range in a Medium Carbon Steel

et al. 2004

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The time-temperature-transformation (TTT) diagram within the medium temperature range of medium carbon steel has been determined. A single type of C-curve is found within the bainite temperature range for the studied steel. Distinct reaction C-curves were not observed for both types of microstructure, upper bainite and lower bainite in the TTT diagram. Experimental results on the kinetics of the isothermal formation of bainite at different temperature have demonstrated that both type of microstructure, upper and lower bainite, possesses similar overall transformation kinetics. Some applications of phase transformation theory towards the formation of bainitic microstructures are discussed, with particular emphasis on the bainite start temperature, transition temperature from upper to lower bainite, martensite start temperature and the thickness of bainitic plates.

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Internal Stresses in Iron and Steel

Cited by 73 publications

References 0 publications

Evaluation of the Hot Ductility of a C–Mn Steel Produced from Scrap Recycling

Evaluation of the Hot Ductility of a C–Mn Steel Produced from Scrap Recycling

Thermal and Mechanical Stability of Retained Austenite in Aluminum-containing Multiphase TRIP Steels.

Time-Temperature-Transformation Diagram within the Bainitic Temperature Range in a Medium Carbon Steel

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Internal Stresses in Iron and Steel

Cited by 73 publications

References 0 publications

Evaluation of the Hot Ductility of a C&ndash;Mn Steel Produced from Scrap Recycling

Evaluation of the Hot Ductility of a C&ndash;Mn Steel Produced from Scrap Recycling

Thermal and Mechanical Stability of Retained Austenite in Aluminum-containing Multiphase TRIP Steels.

Time-Temperature-Transformation Diagram within the Bainitic Temperature Range in a Medium Carbon Steel

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Evaluation of the Hot Ductility of a C–Mn Steel Produced from Scrap Recycling

Evaluation of the Hot Ductility of a C–Mn Steel Produced from Scrap Recycling