Calculation of solidification-related thermophysical properties for steels

Miettinen, Jyrki

doi:10.1007/s11663-997-0095-2

Cited by 187 publications

(94 citation statements)

References 42 publications

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“…It is interesting to note that the MTMR of heat 3 is higher than MTMR of heat 4 at the mold exit whereas the depth of crack of heat 3 (12.6 mm) is deeper than its depth of heat 4 (9.2 mm) [16]. This is due to the effect of position of neutral axis on the mechanical stress distribution in the coherent shell [33]. Another reason comes from examination of the computed MTMR histories where the effect of surface reheating reduces the growth rate of MTMR based upon the reheating degree as shown in Figure 5(d) [6,15,44].…”

Section: Casementioning

confidence: 95%

“…[28] whereas the functions for calculating the equilibrium partition, diffusion coefficients and thermo-physical properties are illustrated in Refs. [29][30][31][32][33]. The temperature-dependent conductivity and enthalpy functions for multi-component alloying elements or impurities for plain steels and their different phases are fitted from measured data compiled by Harste [32].…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Casementioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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

El-Bealy¹

2013

MSA

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“…Los términos ρ, C p , y κ representan respectivamente la densidad, el calor específico y la conductividad térmica del material, todas ellas consideradas dependientes de la temperatura usando la metodología para el cálculo de propiedades termo-físicas de acuerdo a Miettinen (1997).…”

Section: Modelo Acoplado Temperaturas/oxidaciónunclassified

Caracterización de la reacción de oxidación superficial y su influencia sobre la absorción de radiación durante el proceso de temple superficial con láser para el acero 42CrMo4

Cordovilla

Domínguez²,

Sancho³

et al. 2016

REVMETAL

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RESUMEN:El temple superficial con láser es un proceso en el que se depositan elevadas expectativas por sus innumerables ventajas en términos de calidad y productividad frente al temple por inducción. Su implantación efectiva, no obstante, se está viendo lastrada ante la falta de herramientas predictivas fiables y flexibles. Existen diversos modelos para el cálculo de temperaturas, aunque pocos realizan un tratamiento exhaustivo de la oxidación superficial y sus importantísimas implicaciones sobre la absorción de radiación láser. Este artículo adopta un modelo acoplado temperaturas/oxidación disponible en la literatura, utilizándolo, por primera vez, para la simulación de procesos sencillos llevados a cabo en distintas condiciones de potencia y velocidad, para el acero 42CrMo4. Dichas condiciones han sido reproducidas experimentalmente, registrando la temperatura máxima superficial y el espesor de óxido generado. Ambos resultados han mostrado un elevado grado de coincidencia con los resultados teóricos, avalando la fiabilidad y utilidad del modelo.PALABRAS CLAVE: Absorción; Acero; Láser; Oxidación; Superficial; Temple Citation / Cómo citar este artículo: Cordovilla, F., Domínguez, J., Sancho, P., García-Beltrán, A., Ocaña, J.L. (2016) "Caracterización de la reacción de oxidación superficial y su influencia sobre la absorción de radiación durante el proceso de temple superficial con láser para el acero 42CrMo4". Rev. Metal. 52(2):e067. doi: http://dx.doi.org/10.3989/ revmetalm.067. ABSTRACT: Characterization of the surface oxidation reaction and its influence on the radiation absorption during the surface laser hardening process of the 42CrMo4 steel.Surface laser hardening of steel is a process that produces an enormous interest due to its uncountable advantages in terms of quality and productivity against induction hardening The effective implantation of this process, nevertheless, is been hampered because of the lack of reliable and flexible predictive tools. There are different models focused on the temperature calculation, thought, few make a thorough analysis of the surface oxidation associated with the process and its important implications over the absorption coefficient. This work proposes and explains a coupled model temperature/ oxidation available in literature, applied, for the first time, for the simulation of simple processes carried out with different conditions of power and speed, for the 42CrMo4 steel. These conditions have been reproduced experimentally, tracking the maximum surface temperature and the oxide thickness. Both results have shown a high degree of coincidence whit theoretical predictions, confirming the capabilities and utility of the model.

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“…...... (12) where a×b is the size of billet, le is the effective mold length, Q is mold water flow, Tin is the inflow temperature of mold water and Tout is the outflow temperature of mold water. The temperatures are obtained in different casting speed, so A, B can be evaluated by least square method.…”

Section: Model Calibrationmentioning

confidence: 99%

“…It is assumed that thermal properties ρ, ceff and keff are functions of T and of steel components. [10][11][12] Considering the symmetry, one quarter of the billet slice (transverse cross section) is selected to be the calculation domain. Each slice starts at the meniscus (assumed flat) and moves along the strand through the mold, secondary cooling zones (SCZ) and the air cooling zone sequentially.…”

Section: Introductionmentioning

confidence: 99%

Real-time Heat Transfer Model Based on Variable Non-uniform Grid for Dynamic Control of Continuous Casting Billets

Yang

Xie

et al. 2014

ISIJ Int.

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A real-time heat transfer model has been developed for dynamic control of continuous casting billets. In order to fulfill the real-time requirements for efficiency and accuracy, finite volume method (FVM) and alternating direction implicit algorithm (ADI) have been selected as the efficient numerical solution algorithm. And most important of all, variable non-uniform grid and variable time step have been adopted in the algorithm, accelerating the calculation of heat transfer model by 20-40 times. Further, the algorithm's discretization parameters including the grid, time step and slice distance have been optimized by error control (< 3°C), improving the relative calculation time to 0.57. The real-time model has been calibrated by surface temperature measurements using a thermal infrared imager, and its online performance has been tested, within ±13°C of the measurements. After the calibration, the model has been applied to the dynamic control of secondary cooling and the dynamic control of the electric current of final electromagnetic stirring (FEMS), providing the surface temperatures and mushy zone radius at the installation position of FEMS. The latter has been validated by shell-thickness measurements using nail-shooting (relative error< 2.3%). The model-based dynamic control systems controlled the surface temperatures and the flow in mushy zone precisely with changing casting conditions, and have improved the billet quality obviously and reduced the fractures of rolling line during wire-drawing to 1/6 times per month in average from 2-3 times before.

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Calculation of solidification-related thermophysical properties for steels

Cited by 187 publications

References 42 publications

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

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

Caracterización de la reacción de oxidación superficial y su influencia sobre la absorción de radiación durante el proceso de temple superficial con láser para el acero 42CrMo4

Real-time Heat Transfer Model Based on Variable Non-uniform Grid for Dynamic Control of Continuous Casting Billets

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