scholarly journals Dispersion strengthening in vanadium microalloyed steels processed by simulated thin slab casting and direct charging Part 2 – Chemical characterisation of dispersion strengthening precipitates

2007 ◽  
Vol 23 (5) ◽  
pp. 519-527 ◽  
Author(s):  
J. A. Wilson ◽  
A. J. Craven ◽  
Y. Li ◽  
T. N. Baker
Keyword(s):  
Microalloyed Steels ◽  
Dispersion Strengthening ◽  
Thin Slab ◽  
Thin Slab Casting ◽  
Slab Casting

scholarly journals Vanadium Microalloyed Steel for Thin Slab Casting and Direct Rolling

2005 ◽  
Vol 500-501 ◽  
pp. 237-244 ◽  
Author(s):  
Yu Li ◽  
T.N. Baker
Keyword(s):  
Grain Size ◽  
Yield Strength ◽  
Grain Structure ◽  
High Yield ◽  
Microalloyed Steels ◽  
Dispersion Strengthening ◽  
Thin Slab ◽  
Thin Slab Casting ◽  
Slab Casting ◽  
Direct Rolling

Vanadium microalloyed steels with high yield strength (»600MPa), good toughness and ductility have been successfully produced in commercial thin slab casting plants employing direct rolling after casting. Because of the high solubility of VN and VC, most of the vanadium is likely to remain in solution during casting, equalisation and rolling. While some vanadium is precipitated in austenite as cuboids and pins the grain boundaries, a major fraction is available for dispersion strengthening of ferrite. Despite a coarse as-cast grain size, significant grain refinement can be achieved by repeated recrystallisation during hot rolling. Consequently, a fine and uniform ferrite grain structure is produced in the final strip. Increasing the V and N levels increases dispersion strengthening which occurs together with a finer ferrite grain size. The addition of titanium to a vanadium containing steel, decreases the yield strength due to the formation of V-Ti(N) particles in austenite during both casting and equalisation. These large particles reduced the amount of V and N available for subsequent precipitation of fine (~5nm) V rich dispersion strengthening particles in ferrite.

Modeling of the Microstructural Evolution and Mean Flow Stress during Thin Slab Casting/Direct Rolling of Niobium Microalloyed Steels

2005 ◽  
Vol 500-501 ◽  
pp. 221-228 ◽  
Author(s):  
Fulvio Siciliano ◽  
L.L. Leduc
Keyword(s):  
Flow Stress ◽  
Microalloyed Steels ◽  
Hot Strip Mill ◽  
Thin Slab ◽  
Mean Flow ◽  
Thin Slab Casting ◽  
Slab Casting ◽  
Mean Flow Stress ◽  
Direct Rolling ◽  
The Mean

Mill logs obtained from the Hylsa CSPTM (thin slab casting/direct rolling – TSC/DR) mill were examined so that the mean flow stresses at each pass were calculated using the Sims equation modified to take into account the forward slip ratio, the redundant strain and the work roll flattening. The mean flow stresses were then compared to predicted values obtained from a model. The microstructures during the CSP process were predicted by a mathematical model which was initially derived for conventional slab/roughing mill/hot strip mill (HSM) processing route. The adapted model takes into account the deformation of the as-cast structure in the finishing CSP mill, by using particular microstructural equations to calculate the softening kinetics and grain sizes. The main metallurgical features such as the occurrence of Nb(C,N) precipitation, the softening mechanism which takes place (static or metadynamic recrystallization) as well as the strain accumulation between passes were calculated. The mean-flow-stress results obtained from the calculations are in good agreement with the mill data. The present analysis indicates that it is possible to produce fine-grained microalloyed steels with homogeneous microstructure in thin slab casting/direct rolling processing.

scholarly journals Primary Recrystallization Behaviors of Hi-B Steel with Lower Initial Nitrogen Produced by the Thin Slab Casting and Rolling Process

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 189
Author(s):  
Bing Fu ◽  
Li Xiang ◽  
Jia-Long Qiao ◽  
Hai-Jun Wang ◽  
Jing Liu ◽  
...  
Keyword(s):  
Grain Size ◽  
Electron Microscope ◽  
Nitrogen Content ◽  
Rolling Process ◽  
Primary Recrystallization ◽  
Thin Slab ◽  
Nitriding Temperature ◽  
Thin Slab Casting ◽  
Slab Casting ◽  
Inhomogeneity Factor

Based on low-temperature high-permeability grain-oriented silicon steel designed with an initial nitrogen content of 0.0055% and produced by the thin slab casting and rolling process, the effect of total nitrogen content and nitriding temperature on primary recrystallization microstructure and texture were studied by optical microscope, scanning electron microscope, transmission electron microscope, and electron backscatter diffraction. The nitriding temperature affects the primary recrystallization behaviors significantly, while the total nitrogen content has a small effect. As the nitriding temperature is 750–850 °C, the average primary grain size and its inhomogeneity factor are about 26.58–26.67 μm and 0.568–0.572, respectively. Moreover, the texture factor is mostly between 0.15 and 0.40. Because of the relatively sufficient inhibition ability of inherent inhibitors in a decarburized sheet, the nitriding temperature (750–850 °C) affects the primary recrystallization microstructure and texture slightly. However, as the nitriding temperature rises to 900–950 °C, the average primary grain size and its inhomogeneity factor increase to 27.75–28.26 μm and 0.575–0.578, respectively. Furthermore, because of the great increase on the area fraction of {112} <110> grains, part of texture factor is increased sharply. Therefore, in order to obtain better primary grain size and homogeneity, better texture composition, and stability of the decarburized sheet, the optimal nitriding temperature is 750–850 °C.

Numerical Investigation of Shell Formation in Thin Slab Casting of Funnel-Type Mold

2014 ◽  
Vol 45 (3) ◽  
pp. 1024-1037 ◽  
Author(s):  
A. Vakhrushev ◽  
M. Wu ◽  
A. Ludwig ◽  
Y. Tang ◽  
G. Hackl ◽  
...  
Keyword(s):  
Numerical Investigation ◽  
Shell Formation ◽  
Thin Slab ◽  
Thin Slab Casting ◽  
Slab Casting
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