Formation of fine intragranular ferrite in cast plain carbon steel inoculated by titanium oxide nanopowder

Nedjad, S. Hossein; Farzaneh, Amir

doi:10.1016/j.scriptamat.2007.07.016

Cited by 57 publications

(30 citation statements)

References 10 publications

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“…7) Furthermore, recent research works have reported laboratory scale investigations aiming at the dispersion of nanopowders based on liquid metallurgy with promising results. 8,9) Hence, the addition of appropriate non metallic nanoparticles into a liquid steel matrix involves the understanding of high-temperature wetting behavior in liquid metal/solid ceramic system that is critical for improving industrial liquid phase-assisted processes and the quality of the final product. Methods to characterize the wettability are diverse, however, most interfacial properties of liquid steel on solid oxides have been investigated by the sessile drop technique.…”

Section: Introductionmentioning

confidence: 99%

Wetting Behavior of Sintered Nanocrystalline Powders by Armco Fe and 22CrNiMoV5-3 Steel Grade Using Sessile Drop Wettability Technique

Amondarain

Kolbeinsen

Arana³

2011

ISIJ Int.

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The wettability of sintered nanocrystalline oxide powders (CeO2, TiO2, Y3Al5O12, and ZrO2-yttria stabilized) and Al2O3 basis powder (60-70% purity) (product originated in the secondary aluminium production, composed mainly of nano and micrometric aluminium oxide) by liquid Armco Fe and by 22CrNiMoV5-3 steel grade was studied using sessile drop wettability technique. The powders were pressed and sintered under different pressures, heating rates and holding times. The later grinding and polishing surface treatments were characterized by infinite focus microscope. The wetting experiments were carried out under pure Ar atmosphere. A small piece of Armco Fe and steel grade was melted on sintered nano oxides, heating up to 1 600°C with a holding time of 10 minutes for each experiment. The contact angles were measured and chemical analyses were conducted on tested samples to characterize the wetting reactions. It was found that sintered nano TiO2 not only suffered considerable wetting by Armco Fe and 22CrNiMoV5-3 steel in both cases, but also reacted with the substrate to form ilmenite and pseudobrookite. The CeO2 substrate and Armco Fe system also showed good wetting behavior. In general terms, it was concluded that wettability was affected by substrate chemical composition, and surface characteristics by sintering conditions. The preliminary results of this investigation may help to determine the suitability of the nanoparticle to be added in a liquid iron based matrix in order to influence the microstructure evolution improving mechanical properties by a fine distribution in the metallic alloy.KEY WORDS: high temperature wettability; metal/ceramic system; sessile drop technique.

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Section: Introductionmentioning

confidence: 99%

Wetting Behavior of Sintered Nanocrystalline Powders by Armco Fe and 22CrNiMoV5-3 Steel Grade Using Sessile Drop Wettability Technique

Amondarain

Kolbeinsen

Arana³

2011

ISIJ Int.

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“…The introduced oxide particles could affect decomposition of austenite during subsequent cooling by either increasing the number of intragranular nucleation sites or retarding the growth velocity of the ferrite. 8) However, according to the thermodynamic simulations and transmission electron microscopy results found in this work, it appears that C is mainly stabilized by Ti-rich phases and if CO(g) is formed, it is a minor phase. Consequently, the reaction proposed by Hossein to stabilize C and originate solute depleted zones can not be considered here as the mechanism for refining ferrite grain size.…”

Section: Microstructure Characterizationmentioning

confidence: 48%

“…S. Hossein Nedjad et al have put forward that after TiO 2 addition to plain carbon steel 8) and CMn steel 33) a thermodynamically favored chemical reaction of titanium oxide nanoparticles with dissolved carbon occurs during melting and solidification. Then, the chemical reaction between solid carbon and solid titanium oxide is given by: 2CðsÞ þ TiO 2 !…”

Section: Microstructure Characterizationmentioning

confidence: 99%

“…6) However, recent research works have reported laboratory scale investigations based on the liquid metallurgy route with promising results aiming at the dispersion of nanophase particles in low alloy steel grades, but there is still very little research work found in the literature. K. Verhiest et al 7) introduced a dispersion of nanosized yttrium oxides particles into a steel matrix and concluded that the upper temperature limit in mechanical creep strength can be enhanced by at least 100 K. Furthermore, Hossein et al 8) concluded in their work that when titanium oxide nanopowder is inoculated in plain carbon steel, fine intragranular ferrite is formed. Besides, particle incorporation into a liquid metal matrix is associated with mechanical and thermodynamic barriers in terms of wettability.…”

Section: Introductionmentioning

confidence: 99%

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Mechanical Properties and Phases Derived from TiO<sub>2</sub> Nanopowder Inoculation in Low Carbon Steel Matrix

et al. 2013

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The effect of TiO 2 nanoparticle addition on mechanical properties of low carbon steel and the phases originated from this inoculation were investigated. Equilibrium phases were estimated by means of thermodynamic modeling and the results were compared with further microscopy characterization. Both techniques confirmed the dissolution of TiO 2 nanoparticles in the molten steel which derived in TiN and Ti 4 C 2 S 2 nanometric reaction products. The formation of these nanometric phases, were found to result in ferrite grain refinement and consequently in the enhancement of mechanical properties. In addition, the formation of these phases led to C and N depletion from the iron matrix and to a continuous yielding behavior in tensile stressstrain curves.

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“…Corresponding experiments with the TiO 2 addition into liquid steel were not found in the literature, but an addition of TiO 2 within the steel charge before melt down has been reported. [26,27] The further goals for this research were to test and evaluate the inoculants systems for low-alloyed steel in the experimental heats; to analyze the ingots chemistry, as-cast structure, and inclusions size and distribution; and to compare the results from the heats with a TiO 2 addition and without a TiO 2 addition. The effect of the inclusions on grain refinement and the formation of acicular ferrite also were investigated for some specific samples through hot rolling experiments followed by controlled cooling and heat treatment.…”

Section: Introductionmentioning

confidence: 99%

Addition of Dispersoid Titanium Oxide Inclusions in Steel and Their Influence on Grain Refinement

Kiviö

Holappa

Iung

2010

Metall Mater Trans B

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In this article, the addition of dispersoid titanium oxide inclusions into liquid steel, the effect of additions on the inclusions found in the steel and on grain refinement, and acicular ferrite formation were studied. Different TiO 2 -containing materials and addition procedures into liquid steel were tested in experimental heats to obtain inclusions that promote grain refinement and acicular ferrite formation in C-Mn-Cr steel. Different additives with metallic Ti and TiO 2 were added into the steel melt just before casting or into the mold during casting to create Ti-containing inclusions. The aluminum content in steel was lowered by an addition of iron oxide. The samples taken from steel melts and ingots were studied with a scanning electron microscope to find inclusions and to analyze them. Thermodynamic calculations showed that the Al content should be low (<50 ppm) to obtain Ti oxide dominating inclusions, whereas Al 2 O 3 were formed at higher Al contents. When TiO 2 was added late before casting, the oxide inclusions were Ti oxides and were mixed with Ti, Al, and Mn oxides. Small inclusions around 1 lm were detected in the samples with TiO x or TiN as the main component. It could be concluded that the additions resulted in a clearly higher number and in a smaller size of TiO x inclusions than just by adding metallic Ti. Selected samples were brought for subsequent hot rolling and heat-treatment experiments to find out the grain-refining effect and the eventual formation of acicular ferrite. Grain refinement was observed clearly, but the presence of acicular ferrite could not be confirmed definitely.

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Formation of fine intragranular ferrite in cast plain carbon steel inoculated by titanium oxide nanopowder

Cited by 57 publications

References 10 publications

Wetting Behavior of Sintered Nanocrystalline Powders by Armco Fe and 22CrNiMoV5-3 Steel Grade Using Sessile Drop Wettability Technique

Wetting Behavior of Sintered Nanocrystalline Powders by Armco Fe and 22CrNiMoV5-3 Steel Grade Using Sessile Drop Wettability Technique

Mechanical Properties and Phases Derived from TiO<sub>2</sub> Nanopowder Inoculation in Low Carbon Steel Matrix

Addition of Dispersoid Titanium Oxide Inclusions in Steel and Their Influence on Grain Refinement

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