Effect of slag-metal composite cored wire feeding on the cleanness of Al-containing steel

Abstract

The metal yield is low in traditional calcium treatment processing and secondary oxidation of molten steel can be serious. As such, it is of great interest to control the inclusions in steels by feeding the CaO-Al2O3-Ca composite cored wire as an alternative treatment where calcium is protected from sublimation until in contact with the melt. To analyse the effect of composite cored wire on cleanliness of the liquid steel, the evolution of inclusions in steel has been investigated. The initial composition of the calcium aluminate in composite cored wire was changed systematically, and reacted with Al-containing steel to study the effects of starting composition. It can be concluded that when the content of calcium aluminate in the core powder is 80 wt-% to 90 wt-% (the yield is 10%) or the content is 90 wt-% (the yield is 20%), the typical inclusions which have a lower melting point in the steel are spherical CaO-MnO-SiO2-Al2O3, when the calcium aluminate content reaches to 70 wt-% (the yield is 10%) or the content reaches to 70 wt-% to 80 wt-% (the yield is 20%), CaO-MgO-Al2O3 or CaO-Al2O3 is more easily generated in the steel, Al2O3 is gradually reduced.