Formation Mechanism of Inclusions Containing MgO Al2O3 Spinet in Type 304 Stainless Steel

Control of MgO·Al2O3 Spinel Inclusions in Stainless Steels

“…At first, slag entrainment takes place in an AOD converter due to its vigorous stirring by Ar gas after Cr reduction. 17,18,26,[34][35][36][37] For stainless steel 26,36,37) stated that this tendency is enhanced with a decrease in temperature. Similar tendency is reported by the other researcher.…”

“…(17) is not only approximately 1 wt% of Al contained in ferrosilicon alloys but bricks containing alumina also. 36,37) If alumina content exceeds the critical condition of the formation of spinel, they precipitate in aluminosilicate inclusions. The critical condition can be estimated thermodynamically by the following reaction.…”

“…From the phase diagram of the CaO-SiO 2 -Al 2 O 3 -MgO quaternary system, the critical alumina content of the primary crystalline phase of spinel is 20 wt% approximately. [34][35][36][37] Thus, it was recommended to control the content of alumina in the liquid inclusions less than about 20 wt% before solidification.…”

Formation and Evolution of Non-metallic Inclusions in Medium Mn Steel during Secondary Refining Process

“…Some of them [7][8][9][10]12,21,29) thought that the formation of MgO·Al 2 O 3 spinel inclusions depends on the concentration of dissolved Mg, Al and O in liquid steel. Meanwhile, some researchers 18,19,21) found that MgO·Al 2 O 3 spinel could still precipitate from CaO-SiO 2 -Al 2 O 3 -MgO system inclusions during the cooling of liquid steel, although the composition of Mg, Al and O in steel was not in the stable region of MgO·Al 2 O 3 . Additionally, Todoroki et al 16) and Wang et al 20) also proposed SiO 2 in slag would hinder the formation of MgO·Al 2 O 3 inclusions.…”

Effect of Li2O Addition on Crystallization Behavior of CaO–Al2O3–MgO Based Inclusions

“…It is well known that non-metallic inclusions will degrade the quality of clean steel especially regarding mechanical properties and workability. Thus, numerous efforts have been made to control the composition of the non-metallic inclusions in molten steel [1][2][3][4][5][6] and the morphology of inclusions in solid phase steel. [7][8][9][10][11] The behavior of non-metallic inclusions in solid phase steel has been investigated mainly for Si-killed steel.…”