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

Abstract

Experiments with different titanium addition were carried out in alumina crucible without slag at 1 873 K to investigate the variation of inclusion composition, size and morphology in Al-Ti-Ca complex deoxidized steel. The samples exacted from the experimental steels were analyzed by field emission scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS). Titanium influence significantly on the morphology, size distribution and composition of oxide inclusions in Al-Ca deoxidized steels, and the inclusions characteristics vary with titanium content. Liquid oxide inclusions are promptly modified by titanium. On the other hand, titanium can also change solid calcium aluminate inclusions into spherical ones in the melts similarly, but there are a number of inhomogeneous inclusions in molten steel at the initial stage. Therefore, to modify inclusions better, the content of titanium and calcium in molten steel should be controlled simultaneously during the production process.

Evolution Mechanism of Inclusions in Al-killed, Ti-bearing 11Cr Stainless Steel with Ca Treatment

“…The presence of titanium in Al-killed molten steel generally causes more severe clogging of the submerged entry nozzle than Ti-free steel, and the titanium oxide inclusions have been suggested as a possible cause. [26][27][28] Thus, many studies of nonmetallic inclusions in Al-killed Ti-bearing steel have been carried out, such as nozzle clogging behavior, 26,28) thermodynamics and characteristics of inclusions, [29][30][31][32][33][34][35][36][37][38][39][40] modification of inclusions with Ca treatment [41][42][43][44][45][46][47] or Mg treatment [48][49][50][51][52] and evolution of inclusion during solidification and heating. 41,48,[53][54][55] The two-layered inclusions of the Al-Ti-O phase with core Al 2 O 3 were observed in Al-killed Ti-bearing molten steel, which was identical to the inclusions causing the nozzle clogging.…”

Evolution mechanism of inclusions during refining and continuous casting process of 321H stainless steel

“…For Al-killed molten steel, calcium treatment is carried out as a routine technology in steelworks in order to solve the clogging of SEN during CC process, which can effectively modify the solid alumina and spinel (MgO•Al 2 O 3 ) inclusions to liquid calcium aluminate inclusions [40][41][42]. Many researchers [40][41][42][43][44][45][46][47][48] have investigated the evolution mechanism, reaction steps and reaction kinetics, morphology and size characteristics of aluminate-based inclusions in Al-killed molten steel during calcium treatment process on both thermodynamics and experiment scale. It was found that the evolution followed route of 'Al 2 O 3 →MgO•Al 2 O 3 →CaO-Al 2 O 3 -MgO' during the refining process [39,41,42].…”

Effect of Ti Addition on Non‐Metallic Inclusion Characteristics in TRIP Steel

“…The effects of Ti addition on inclusions in Alkilled steels have been widely investigated, including the effect of the sequence of Ti addition, Ti/Al ratio, Ti content, and evolution behavior of inclusions. [17][18][19][20][21][22] Zheng et al [23,24] investigated Al-Ti complex deoxidization and concluded that the evolution of inclusions depended strongly on the Al content. Kim and Thapliyal et al [25,26] reported that Mn-Si-O inclusions decreased in number and even disappeared upon addition of Ti to molten steel.…”