Stainless Steel 용해시 탈산효과 (2) : Stainless 강의 규소에 의한 탈산 The Deoxidation of Stainless steel with silicon in Melting = Study on the Deoxidation of Stainless Steel in melting (2)

국문 초록 (Abstract)

18Cr-8Ni과 stainless鋼 scrap을 高周波誘導爐에서 熔解시킬 때 脫크롬의 現象, 脫酸現象 및 Slag의 浮上機構와 鋼中 分解物의 結晶構造에 對하여 調査하였다.
17Cr stainless鋼을 熔解할 때 熔解時間이 延長될수록 脫크롬率이 增加하였으며 特히 1時間 以後부터는 脫크롬率이 顯著하게 增加하였다. 18Cr-8Ni stainless鋼의 경우는 脫크롬率이 微少하였으며 1 時間동안 熔解시킨 後 1600℃에서 2時間동안 維持하여도 1.67%의 낮은 脫크롬率을 보였다.
熔湯中의 介在物이 球狀으로 凝集할 때에 鋼內의 介在物含量이 적었으나 分散狀態로 介在할 때는 熔湯으로부터의 浮上速度가 늦어져 介在物含量이 增加하였다. 本 實驗에서 製造한 試料, 卽 珪素 0.8% 以下, 망간1.0% 以下를 含有하고 있는 18Cr-8Ni과 17Cr stainless鋼中 各各의 介在物을 抽出하여 X-線分析한 結果 Cr₂O₃와 Fe₃O₄의 peak가 나타났으며 介在物中의 Mn, Si等의 結晶質化合物의 peak는 나타나지 않았다.

다국어 초록 (Multilingual Abstract)

The phenomenon of decreasing chromium content, the effect of deoxidation by adding silicon and the floating mechamism of slags, the crystal structre of inclusions for 18Cr-8Ni and 17Cr stainless steel respectively have been investigated. The scraps are melted by a high frequency induction furnace.
The results are as follows;
(1) The chromium content in 17Cr stainless steel exhibits a remarkable decrease more than 1 hr. is required for melting the scrap. The chromium content in 18 Cr-8 Ni stainless steel exhibits a small decrease, as 1.67% until holding for 2 hrs. The required melting time is 1 hr.
2) The floating rate of spheroidal inclusions is greater than the floating rate of dispersed inclusions from molten bath.
3) The slags of 17 Cr stainless steel before deoxidation and after deoxidation by adding silicon are FeO·Cr₂O₃and SiO₂, the slag of 18 Cr-8 Ni stainless steel is FeO·Cr₂O₃, which can be seen by X-ray diffraction.
4) The inclusions in 18Cr-8Ni and 17Cr stainless steel (containing less than 0.8% Si and less than 1.0% Mn, as cast) are Cr₂O₃and Fe₃O₄ as can be seen by X-ray diffraction.