18Cr-8Ni stainless 鋼 scrap을 熔解處理한 後 時間經過에 따라 試料를 採取하여 介在物의 크기를 測定하고 이들 介在物들을 抽出하여 稱量 및 X-線檢査를 하였다. 그 結果를 要約하면 다음과 같다. 1) 熔落後 維持時間이 經過할수록 介在物含量은 熔解直後 0.47%에서 2時間經過後 0.13%로 減少하였으며 介在物의 平均粒經은 熔解直後 2.0μ에서 2時間經過後 4.2μ까지 增加하였다. 2) Fe-Cr 處理한 試料의 介在物은 含量에는 크게 變化가 없고 介在物粒徑을 크게 하였다. Fe-Si 處理한 試料의 介在物은 微細한 粒狀으로 存在하였으며, 이 경우 介在物含量은 크게 增加하였다. 이것은 介在物이 微細할 경우 그 形態가 球狀이면 介在物含量이 적고 球狀이 아닐 때는 含量이 많은 傾向을 보였다. 3) Br-Methanol法으로 抽出한 介在物중의 Br이 free Br으로 含有되어 있으면 Br의 沸點이 58.75℃ 이므로 100℃로 乾燥할 경우, Br이 모두 揮發除去되어야 하는데 100℃로 乾燥한 介在物중에 Br이 많이 含有되어 있는 것으로 보아 이 Br은 Fe 酸化物 및 Cr酸化物과 함께 非晶質의 化合物을 形成하고 있는 것으로 生覺 된다. 4) 抽出한 介在物을 1000℃로 加熱하였더니 주로 Fe₃O₄및 Cr₂O₃의 結晶임을 알 수 있었으며, 이 때 介在物의 重量은 100℃로 加熱한 介在物에 비하여 約 7% 減少되었다. 또 이 重量減少가 일어난 介在物을 X-線螢光分析 하였더니 Br의 peak가 나타나지 않았다.

After melted down the scraps of 18Cr-8Ni stainless steel in the high frequency induction furnace, the samples were obtained at various holding time. With the increase of holding time, the average inclusion size and inclusion contents were measured by means of optical microscopy and Br-Methanol method And the behaviours of inclusions were studied by the X-ray technique. From above experiment. the following results were withdrawn. 1) With increasing holding time after melted down, the inclusion contents and average inclusion size were decreased and increased respectively; from 2.0 and 0.47% just after melted down to 4.22 and 0.13% after 2 hours. 2) In the case of the inclusions of Fe-Cr treated sample, the content was not changed but the size was increased compared with the inclusion content of just holding sample after melted down, The type of inclusion of Fe-Si treated sample was very fine and granulous. In this case, the content of inclusion was remarkably increased. In the case of fine inclusions, the inclusion content of granula shape was more than that of spheroidal shape. 3) In spite of the low bailing point of bromine(58.78℃) the dried inclusions at 100℃ which were extracted from Br-Methanol method were still contained bromine. This was the direct result that the bromine formed amorphous compound with iron oxide and chromium oxide. 4) The extracted inclusions which were dried at 1000℃ were crystallized to Fe₃O₄and Cr₂O₃. And the weight decrease was 7% compared with the inclusions dried at 100℃. And by the X-ray fluorescence analysis, the bromine peak was not detected in dried inclusions at 1000℃.