Tundish Nozzle Constriction in Continuous Casting of Titanium Bearing Stainless Steel Slabs

Thermodynamic Interaction between Chromium and Titanium in Liquid Fe–Cr Alloys Containing 30 mass% Cr

“…Solid TiN precipitate started to form on the melt surface as the melt temperature decreased below 1 873 K. After an equilibration time of 1 h at 1 823 and 1 793 K, metal samples were taken and water quenched. The nitrogen and titanium contents in metal samples taken at 1 823 and 1 793 K are shown as symbols [3] and [4] in Fig. 10, respectively.…”

“…[1][2][3] On the other hand, an excessive formation of those inclusions can cause a nozzle clogging problem during continuous casting and various defects in final products. [4][5][6] In order to control those inclusions during steel processing, it is essential to have accurate thermodynamic information of titanium in liquid stainless steels containing high chromium. In spite of its importance, the thermodynamic relation between chromium and titanium in liquid Fe-Cr-Ti alloys is not consistent in the literature, [7][8][9][10][11] and little information is available at temperatures other than 1 873 K.…”

Thermodynamics of the Formation of MgO-Al2O3-TiO x Inclusions in Ti-Stabilized 11Cr Ferritic Stainless Steel

“…Clogging phenomena of SEN or tundish nozzle during continuous casting of Ti-stabilized stainless steels have been investigated by several researchers. Hasegawa et al [1] observed that the constriction of tundish nozzle becomes more severe as the ratio of Al 2 O 3 to TiN increases and that the main origin of these particles is the reaction between aluminum in the stainless steel melt (type 321) and silica in the refractory, as well as the reaction products in deoxidation and nitrogen removal processes. They assumed that the buildup originated not only from the deposition of nonmetallic inclusions, but also from freezing of the steel.…”

“…In view of productivity of the melt shops and surface quality (sliver, flaw, or crack) of steel products, it is desirable to have the amount of inclusions as low as possible. [1][2][3][4][5][6][7] On the contrary, the use of inclusions is expected to help produce fine grains during primary solidification, which is preferable to other methodologies such as controlled deformation and heat treatment. [8,9] In these studies, the MgAl 2 O 4 spinel inclusion could accelerate the formation of TiN in molten steel due to very low disregistry between them, and finally an equiaxed fine-grained structure was produced by the heterogeneous nucleation of delta ferrites on the TiN particles.…”

“…The equilibrium deoxidation reaction by aluminum and silicon is given in Eqs. [1] and [3], respectively. [18,19] 2½Al…”