| 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 the following results were withdrawn. 1) With increasing holding time after melted down, the inclusion contents and average inclusion size were decreased and increased respectively; from 2.0 and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℃. |
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