Hot rolling texture development in CMnCrSi dual-phase steels

Waterschoot, Tom; Kestens, Léo; Cooman, Bruno C. De

doi:10.1007/s11661-002-0211-5

Cited by 48 publications

(18 citation statements)

References 7 publications

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“…The ferrite b-fibre is the transformation product from the austenite b-fibre, which represents the characteristic texture components of the deformed FCC material with high stacking fault energy (SFE). 15,16) A rotated cube recrystallization texture component {001}͗110͘ is also presented in the ODF with the intensity of 2ϫ.…”

Section: Resultsmentioning

confidence: 99%

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Microtexture of Thin Gauge Hot Rolled Steel Strip.

et al. 2003

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A series of trials were conducted on a compact rolling mill to evaluate the properties and characteristics of carbon steel strip hot rolled to less than 2 mm in thickness from thin cast slabs. Steels of two different compositions were studied, the first one, a low carbon steel, was rolled to a total reduction ranging from 94 to 98 %, final thickness ranging from 1.06 to 2.69 mm, whereas the second one was a Nb bearing microalloyed steel rolled to a total reduction of around 96 %. The rolling trials were complemented by means of computer modelling to get a deeper understanding of the process. It was found that the ferritic grain size of the low carbon strips varied from 7 to 10 mm, with the finer sizes found in the thinner strips, the grain size of the microalloyed steel was found to be 3.6 mm. Analysis of the texture of the hot rolled strips indicated that the ferrite in the low carbon resulted from the transformation of recrystallized austenite, in comparison, low intensity transformation texture from unrecrystallized austenite was found in the Nb bearing steel. The observed texture data correlate with the R-values measured.KEY WORDS: hot rolling; steel; texture; microstructure.used with steel of composition A (identified as A1, A2 and A3), whereas only one schedule, similar to that of A2, was applied with steel B. All the samples from either type of materials were cut at room temperature from the coiled product. Coiling of the strips take place at the end of the run out table, which is equipped with a cooling system. The cooling system consists of a series of low pressure laminar water headers located on the top of the strip and low pressure water jet headers from the bottom side. The number of headers being used was controlled by the operators to assure coiling temperature below 650°C. The chemical composition of the steels is shown in Table 1 and the parameters of the rolling schedules together with the measured R and Dr-values are shown in Table 2. The value of critical temperatures A 1 ϭ718°C and A 3 ϭ860°C were calculated with the equations proposed by Andrews.7) The temperature changes in the strips during rolling were predicted by computer modelling, 8) as this approach allows to have an idea whether the final rolling temperature (FRT) stays within the austenite phase field or within the two phase, aϩg, region. The values shown in Table 2 indicate that the final rolling temperatures predicted by the model were above A 3 , without entering the intercritical region for the rolling schedules A1, A2 and B, but not for the thinnest sample (A3), on which the final pass may have been imparted in the intercritical region.Evaluation of the forming characteristics of the hot rolled steels was carried out by testing tensile samples cut parallel, perpendicular and at 45°with respect of the rolling direction. Individual measurements of the instantaneous width and thickness to the samples were made to obtain the strain values as referred to the width and thickness (e w and e t respectively) of the samples. The plasti...

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Section: Resultsmentioning

confidence: 99%

“…10(d)). According to some authors 2,13,15) these texture components could emerge from either deformed or recrystallized austenite (see Fig. 9(b)), but the later is less probable, taking into account the Nb content of steel B, the rolling parameters and the model predictions.…”

Section: Texturementioning

confidence: 97%

Microtexture of Thin Gauge Hot Rolled Steel Strip.

et al. 2003

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“…el esfuerzo de fluencia y el esfuerzo tensil máximo y la ausencia de fluencia heterogénea. En general estos resultados se encuentran en el rango de los aceros HSLA [8] .…”

Section: Caracterización Mecánicaunclassified

Caracterización de aceros dual-phase obtenidos por laminación en caliente

Colás

Houbaert³

2011

REVMETAL

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ResumenSe tomaron muestras de acero al C-Mn-Si disponible en el mercado y mediante un proceso de laminación en caliente y bobinado, se obtuvo acero Dual Phase con microestructura y propiedades mecánicas dentro del rango teórico esperado de este material. El proceso termomecánico consistió en producir una fuerte reducción a temperaturas mayores a A r3 , mediante pasadas de laminación sucesivas, para posteriormente enfriar el acero durante aproximadamente 5 s, (a una velocidad de 20°C/s) en el rango de equilibrio α+γ. La temperatura A r3 , medida mediante calorimetría diferencial de barrido, fue de 890°C. A continuación se realizó un temple en el rango de temperaturas de bobinado (550-675°C), enfriando posteriormente las muestras de acuerdo a una curva pre establecida, que corresponde a la curva de enfriamiento real de una bobina. La caracterización microestructural de las muestras obtenidas, se realizó mediante microscopía óptica, microscopía electrónica de barrido y microscopía de fuerza atómica. Adicionalmente se realizó una medición de texturas mediante difracción de rayos X, para el estudio de las orientaciones resultantes, producto de la variación de la temperatura de término de laminación (TTL) y la temperatura de bobinado (TB), determinándose cómo afectan estas variables a las distintas componentes de texturas. Se complementó la información microestructural con los valores de los índices de anisotropía normal y planar, medidos de acuerdo a la norma ASTM E-517. Se correlacionaron las intensidades de las componentes de texturas encontradas con los valores de los índices de anisotropía, encontrándose que sólo es posible producir leves mejoras en el índice de anisotropía normal, a través de una combinación apropiada de las temperaturas de término de laminación y de bobinado. Palabras claveAceros; Dual-Phase; Laminado en caliente; Texturas; Embutición. Characterization of dual-phase steels obtained by hot-rolling AbstractSamples were obtained from C-Mn-Si steel available in the market. Through a hot rolling and coiling process, it was possible to obtain Dual-Phase steel with microstructural and mechanical properties in the theoretical range typical of this material. The thermomechanical process consisted of a strong reduction by multiples pass of hot rolling at temperatures above A r3 , controlled-cooling the sheets during 5 s (at a rate of 20°C/s in the equilibrium range α+γ. Temperature A r3 measured by differential scanning calorimetry was 890°C. Quenching was then carried out in the coiling temperatures range (500-675°C), cooling the samples in accordance to an established curve that corresponds to the actual cooling curve of a coil. The microstructural characterization of the samples obtained was carried out by optical microscopy, scanning electron microscopy and atomic force microscopy. Additionally, texture measurements were carried out by X-ray diffraction in order to study the resulting orientations due to the finishing rolling temperature and coiling temperature, determining the influence on these par...

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“…Recently, the degradation of ductility and impact toughness of DP steels has been receiving attention and this phenomenon has been attributed to the formation of coarse martensite phases as the intercritical annealing temperature increases [3,5,6]. It has been shown that the ductility and fracture toughness can satisfactorily be optimized by developing microstructures with fine distribution of ferrite and martensite in DP steel either by introducing new alloy design or adopting an appropriate heat treatment procedure [3,6,7]. On the basis of alloying design, the new chemistries are low in carbon and rich in hardenability enhancing element such as…”

Section: Introductionmentioning

confidence: 99%