Effect of MgO on crystallization behavior of MnO–SiO(2)–Al(2)O(3) based inclusions in tire cord steel

Increasingly MgO content in refining slag and molten steel is the major cause of corrosion of refractory materials at slag line during the refining process of Si–Mn deoxidized tire cord steel, the effects on the crystallization behavior of typical MnO–SiO(2)–Al(2)O(3) based inclusions in tire cord steel were studied. The relation between the formation of high melting point and high hardness inclusions (Al(2)O(3), 3Al(2)O(3)·2SiO(2), MgO·Al(2)O(3) and 2MgO·SiO(2)) with MnO–SiO(2)–Al(2)O(3)-(0wt.%, 4wt.%, 8wt.%, 12wt.%, 16wt.%) MgO system was verified by ICP, XRD, SEM-EDS and FactSage 8.0. The results indicated that the crystallization temperature of MnO–SiO(2)–Al(2)O(3) system increases with the increase of MgO content. Mg(x)Mn((2-x))SiO(4)(1 ≤ x < 2) solid solution is the main crystalline phase due to isomorphism. Only a small amount of 2MgO·SiO(2) which is not enough to cause wire breakage was formed in the trial with the highest MgO content (16wt.%) after the low melting point MnO–SiO(2)–Al(2)O(3) composition added different MgO content and the other three kinds of inclusions were not produced in the five trials.