Effect of Carbon Content on the Potency of the Intragranular Ferrite Formation

Abstract

The effect of the carbon content on the potency of the intragranular ferrite (IGF) formation for each inclusion size is investigated in the present work. The TiN inclusion was detected to be the effective nucleation site for the IGF formation in the Fe–0.2 mass% C alloy and the Fe–0.4 mass% C alloy. It is noted that the potency of the IGF formation for each inclusion size is decreased with the increase of carbon content. Moreover, the critical diameters of the TiN, TiO, and VN inclusions in the steels with different carbon contents are calculated based on the classical nucleation theory. The calculated critical diameter is also found to be decreased with the increase of carbon content. This is in agreement with the experiment results. Finally, the decrease of the potency of IGF formation for each inclusion size is due to a larger amount of pearlite formation in the steel containing a higher carbon content, which is detected by differential scanning calorimetry (DSC) measurements.

Inclusion and Microstructure Characteristics in Steels with TiN Additions

“…The critical diameter of TiN inclusions for IGF nucleation has been reported in our previous study . Here, the values of σ Iγ – σ Iα were selected to be 0.337 and 0.197 J m −2 .…”

“…This difference is due to the different interfacial energies of σ Iγ – σ Iα . The critical diameters of TiO, TiN, and VN inclusions for IGF nucleation have been calculated in our previous study …”

On the Capability of Nonmetallic Inclusions to Act as Nuclei for Acicular Ferrite in Different Steel Grades

“…They mostly used artificially added oxide powders like Ti 2 O 3 to create the desired inclusion types because an appropriate tailoring of potent nucleation sites only by deoxidation and desulfurization reactions can be difficult. [21][22][23] However, this might be in contrast to the demands of high-quality steels, which generally require low inclusion contents. The present study investigates the acicular ferrite formation on nonmetallic inclusions on a laboratory scale, with special consideration paid to the importance of the relationship between steel composition and inclusion type.…”

“…Apart from weld metals, most published studies addressed High-Strength LowAlloyed (HSLA) steels. [21][22][23] Therefore, a systematic comparison of the inclusions' effects in different steel grades has been sparsely represented. Therefore, the current study compares four steel grades with significantly different compositions, and their effects on the capability of inclusions to nucleate acicular ferrite.…”

Synthesis of Core-Shell MgO Alloy Nanoparticles for Steelmaking

“…The carbonized NPs were found to exist in a stable form in an appropriate solvent, exhibiting good monodispersity and reduction in the aggregation of the NPs [15,22,23]. In the subsequent process of high-temperature steelmaking, the insignificant amount of carbon found in the coating of the surface-treated NPs exhibited little or no pollution in the molten steel [24].…”