Thermodynamic Model for Prediction of Slag-Steel-Inclusion Reactions of 304 Stainless Steels

Abstract

A thermodynamic model was developed to predict slag-steel-inclusion reactions of 304 stainless steels. The dissolved aluminum in the steel, the sulfur distribution ratio and the composition of inclusions equilibrated with varying slags were predicted using the current model. The model can also be widely used to predict the liquid fraction of inclusions. For Al-killed 304 stainless steels, the optimized composition of CaO-Al 2 O 3 -SiO 2 -MgO slags is proposed to modify solid Al 2 O 3 inclusions to liquid CaO-Al 2 O 3 -MgO at 1 873 K. For Si-Mn-killed 304 stainless steels, the optimized composition of CaO-SiO 2 -MgO-Al 2 O 3 -20%CaF 2 slags is suggested to suppress the formation of Al 2 O 3 -MgO in SiO 2 -CaO-MnO-MgO-Al 2 O 3 inclusions and lower their melting temperatures.

Effect of Cooling Rate on Oxide Inclusions During Solidification of 304 Stainless Steel

“…The ways to reduce the detrimental effects include the removal and modification of inclusions. The removal of inclusions is usually promoted by the control of fluid flow, while the modification of inclusions is usually carried out through slag refining and calcium treatment during secondary refining …”

“…The transformation of inclusions during the process induces the different natures of inclusions in steel products from those in the molten steel. The formation, removal, and modification of inclusions in molten steel have been widely investigated. Meanwhile, the changes of inclusions in solid steel during heat treatment have been paid more and more attention to, especially for stainless steels .…”

Effect of Slag Composition on MgO·Al₂O₃ Spinel-Type Inclusions in Molten Steel

“…Most previous studies evaluated the formation of spineltype inclusions on the basis of thermodynamic calculations. 4,7,8,10) However, when considering the actual process, a kinetic analysis is necessary because the compositions of the molten steel, slag and inclusions change with time. Okuyama et al 11) and Galindo et al 12) analyzed experimental and operational results by using a coupled reaction model which considers the reaction between molten steel and slag, and simulated the changes in the MgO content in Al 2 O 3 -MgO type inclusions by using the changes in the composition of the molten steel.…”

“…[2][3][4][5][6][7][8] Some researchers have pointed out that changes in the slag composition affected the formation of spinel-type inclusions. 2,3,[9][10][11] When the slag basicity CaO/SiO 2 and CaO/ Al 2 O 3 is lower, reduction of MgO in the slag is suppressed. This means that decreasing the slag basicity is effective for suppressing the formation of spinel-type inclusions.…”

Enhancement of Mechanical Properties of AISI304 Stainless Thin Plate by Low-pressure, Repeated Explosive Hardening

“…1,2) However, with the development of aerospace industry and improvement of manufacturing technologies, the performance of AISI304 stainless steel treated with common strengthening processes has not met the desired requirements in these fields. [3][4][5][6] Therefore, to explore an effective method to remarkably strengthen the AISI304 stainless steel has become a vital issue.…”