Study On Behaviour Of Non-metallic Inclusions In Fe-Ni Base Alloy Metallurgical Process

Because of Fe-Ni base alloy's excellent property,it is used very widly in many fields,such as aerospace,petrochemical industry and so on.Traditional module casting process is hard to meet the need of Fe-Ni base alloy.Some enterprises start attempting to use EAF-AOD-LF-CCM process to product Fe-Ni base alloy,aimed at developing continual casting process for it.Therefore,the change rule of the non-metallic inclusions in Fe-Ni base alloy metallurgical process is studied in system in this article,which is very significant for the development of Fe-Ni base alloy metallurgical techology.The transformation rule of the non-metallic inclusions in Fe-Ni base alloy metallurgical process is studied in this article by industrial test.What's more,high temperature simulation experiments were conducted in the lab to explore the generation mechanism of the inclusions containing Mg.The main conclusions are distributed as follows:(1)During Fe-Ni base alloy metallurgical process,except for Al2O3 inclusions,MgO inclusions,Mg-Al-O system inclusions,Ca-Mg-O system inclusions,and Ca-Al-Mg-O system inclusions also formed after Al deoxidation.After Ti addition,TiN inclusions formed,too.After LF fefining,the main inclusions is TiN,and a few Al2O3 inclusions and Ca-Mg-O system inclusions also existed.The type of the inclusions in the casting blank are amost invariant with the inclusions after LF refining.(2)After Ti addition,Al-Ti-O system inclusions could not exist in the Fe-Ni base alloy under the equlibrium condition.If Ti enriched in the alloy or it could not diffuse an time,a few Al-Ti-O system inclusions would form.(3)The main sources of theinclusions containing Mg are as follows:firstly,the reaction between[Al]and the slag;secondly,the refractory peeled off.MgO inlusions and Ca-Mg-O system inclusions have the tendency to taansform to MgO inclusions and Ca-Al-Mg-O system inlusions respectively.(4)[Al]in the Fe-Ni base alloy could reduce the MgO in the slag and made[Mg]enter the alloy.[Mg]enriched in the field close to the interface between the alloy and the slag,which led to the MgO inclusions formation.After MgO inclusions entered the alloy,they would be reduced by[Al]in the alloy and changed to Mg-AL-O system inclusions.