• 作者： 周釋善; 賴文貴
• 作者服務機構： 國立成功大學礦冶及材料科學研究所
• 中文摘要： 本研究於高週波爐中以頂吹方式，高度攪拌，極小的 2 mm 吹距條件下，吹送 Ar/O , Ar/O /II O, H O/O 氣體混合物於 Fe-C-Cr 鋼液上，探討吹入水蒸汽及減壓清況下，對脫碳反應之影響。歸納如下： 1. 吹煉 Ar/O 氣體，脫碳曲線明顯分成兩個部份，其轉折點在 0.04~～0.02% C。碳含量低於此轉折點，速率控制機構為碳擴散及界面阻礙。高於此轉折點，脫碳速率隨氧流量之增加而變大，為氣相傳送控制機構。而吹煉 H O/O 氣體，馬上生成氧化物，山此氧化物問接脫碳，其轉折點一在 0.11～0.07% C 間，一在 0.03～0.01%C 間。 2. 吹入水蒸汽將提高脫碳速率及氧氣利用效率，但會增加鉻的氧化損失。 3. 中途減壓具有去除氫氣，繼續脫碳，減少鉻過度損失，及節省氣體消耗之優點。 4. 減壓吹煉可以提高脫碳速率，氧氣利用效率，減少鉻的氧化損失，得到極低的脫碳終點。如起始含碳量在 0.233%，經 300 mm Hg H O/O2＝3：1，總流量 100 ml/min 之 H O/O2 氣體減壓吹煉經15分鐘，其碳含量降為 0.015%，鉻損失為1.4%，經50分鐘，脫碳終點在 0.005%C，鉻氧化損失為 3.3%，其氫含量為 6.1 ppm。 5. 氫氣在減壓吹煉各爐，其含量在 8 ppm以下，經50 mm Hg 爐壓，減壓除氣1分鐘，氫氣含量降至 5 ppm以下。
• 英文摘要： Decarburizatien of molten Fe-C-Cr, alloyby top blowing Ar/O , Ar/O /H O, H O/O gasmixtures under very small lance height, extremelystirred condition have been studied in a highfrequency induction furnace. Studying the effectof blowing steam and reduced pressure on thereaction of decarburization of molten stainlesssteel, the results are summarized as follows: 1. The curve of carbon concentration vs timeis distinctly divided into two parts under topblowing Ar/O gas mixtures. The critical carbonconcentration is 0.04～0.02%C. When carbonwas lowered less than C , decarburizing rate wasrapidly reduced, the controlling steps of reactionare diffusion of carbon in molten steel. De-carburization rate increases as the oxygen flowrate increases when carbon concentration ofbath is above C , the controlling step is gasphase transport of oxygen. It seems to formoxide simultaneously at the starting of blowingsteam gas, then carbon is removed indirectly byreducing the oxide with carbon dissolved inbath. There are two crictical points on the curveof carbon concentration vs time, one is between0.11～0.07%C, the other is between 0.03～0.01%. 2. It could increase the rate of decarburiz-ation and efficiency of available oxygen but in-crease the oxidation loss of chromium whensteam is injected on the molten Fe-C-Cr alloy. 3. There are many advantages e．g. removinghydrogen gas, further decarburizing, reducingoxidation loss of Cr, saving gas consumption asto reduce the top pressure under an inert at-mosphere at the end of blowing oxygen/steamgases. 4. We could increase the rate of decarburiz-ation and efficiency of oxygen, lower the Crloss, achieve very low final carbon content bytop blowing H O/O gas mixtures under reducedtop pressure. Example: Initial carbon contentis 0.233%, total flow rate 100 ml∕min, gas ratioH O/O = 3:1, 300 mm Hg the carbon content ofbath is changed into 0.015%, Cr loss 1.4%in 15 minutes, and the final carbon content is0.005% C, Cr loss 3.3%, the hydrogen contentof bath 6.1 ppm by blowing the steam/oxygengas mixtures in 50 minutes. 5. The hydrogen content of bath by blowingsteam/oxygen under reduced top pressure are lessthan 8 ppm, and lowered less than 5 ppm bydegassing under 50 mm Hg atmosphere in oneminute.
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