Transformation behavior of a Ti–Zr deoxidized steel: Microstructure and toughness of simulated coarse grain heat affected zone

Effect of ZrO2 nanoparticles on the impact properties of shielded metal arc welds

“…Furthermore, nonmetallic inclusions in the nanometer scale can enhance grain refinement by preventing grain growth due to the pinning of grain boundaries [6]. Several studies have reported that ZrO 2 is a very effective nucleation site for the nucleation of acicular ferrite [2][3][4]. The higher magnification SEM micrograph and EDS elemental maps of weld Z3 is shown in Fig.…”

“…It is obvious that the acicular ferrite plates nucleate on the ZrO 2 inclusions. Wang et al [3] and Guo et al [4] have concluded that the ZrO 2 phase is a very effective nucleation site for the nucleation of acicular ferrite, improving the impact toughness. The ZrO 2 inclusions absorb Mn from the steel matrix and deplete Mn from the austenite.…”

“…This can be attributed to the absorption of Mn into cation vacancies of ZrO 2 inclusions or the formation of MnS at the ZrO 2 inclusions. The formation of Mn-depleted zones around the ZrO 2 inclusions reduces the austenite stability and increases driving force for ferrite transformation and thus promotes the nucleation of acicular ferrite [2,3]. Acicular ferrite with small effective packet size and fine interlocking microstructure with high angle grain boundaries between ferrite plates significantly prevents the initiation and propagation of cleavage cracks.…”

“…Acicular ferrite has been known to intragranulary nucleate at non-metallic inclusions in prior austenite grains during the austenite-ferrite transformation [1]. It has been shown that ZrO 2 , among various non-metallic inclusions, is very effective for the nucleation of acicular ferrite [2][3][4]. No research dealing with welds produced by coated electrodes containing ZrO 2 nanoparticles appears in the literature.…”

Effect of Ti Content on the Characteristics of Inclusions in Al–Ti–Ca Complex Deoxidized Steel

“…3) In addition, Ti-oxide in steel can be nucleating sites for intragranular acicular ferrite during solidification, and improve mechanical properties around welded region in steels. [4][5][6][7][8] However, Ti-containing inclusions may also cause severe nozzle clogging problems, which are detrimental to steel production process. As a result, there are many researches of nonmetallic inclusions in Al-Ti deoxidized steel in recent years, such as thermodynamic, [9][10][11][12][13][14][15][16] size distribution, [17][18][19] modification process 10,11,16,20) and collision character.…”