Nonmetallic inclusion removal of Si-Mn deoxidized steel by nitrogen absorption and release method
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摘要: 以硅錳脫氧的SWRH82B熱軋盤條為實驗鋼種，研究增氮析氮法對硅錳脫氧鋼中夾雜物的去除效果，并設置0.02、0.035、0.05、0.065和0.08 MPa五組增氮壓力進行熱態實驗.實驗結果表明：在1873 K的溫度下，鋼液經過增氮20 min、真空處理30 min后，不同爐次鋼中T[O]均下降至1×10-5以下，最低為4×10-6，T[N]均下降至5×10-6以下，最低為2×10-6，夾雜物去除率均為40%以上，T[O]去除率均大于78%，表明該技術對硅錳脫氧鋼中的夾雜物及T[O]有良好的去除效果.此外，隨著增氮壓力的升高，鋼中T[O]與夾雜物去除率均有所升高，當充氮壓力為0.08 MPa時，T[O]與夾雜物去除率分別達到89.2%和87.4%.理論分析表明，隨著增氮壓力的升高，氣泡形核率增大、鋼中生成氣泡數量增多、鋼中氣泡的密度增加，從而提升氣泡去除夾雜物的效率.Abstract: The micro nonmetallic inclusion and oxygen content in steel significantly affect its performance, and removing the inclusion involves a difficult process. A nitrogen absorption and release method has been developed with which nonmetallic inclusions and T[O] were efficiently removed from bearing steel. However, the inclusions in bearing steel are highly different from those in Si-Mn deoxidized steel, and the effect of the nitrogen absorption and release method on the Si-Mn deoxidized steel remains unclear. Based on this, a thermal experiment was carried out in this study to investigate the removal of nonmetallic inclusions from Si-Mn deoxidized steel by nitrogen absorption and release method, where SWRH82B hot rolled wire coil was used as the experimental steel, and five groups of increasing nitrogen pressure (0.02, 0.035, 0.05, 0.065 and 0.08 MPa) were set up. The results show that for all groups, the T[O] and T[N] in the steel reduce to below 1×10-5 and 5×10-6, respectively, after the molten steel is subjected to 20 min of increasing nitrogen and 30 min of vacuum treatment. The lowest T[O] and T[N] in the steel is 4×10-6 and 2×10-6, respectively, and the inclusion removal rates for all the groups are more than 40%. The T[O] removal rates for all the groups are more than 78%.This result proves that nitrogen absorption and release method is efficient in removing inclusions and T[O] in Si-Mn deoxidized steel. Furthermore, the removal rate of inclusion and T[O] in the steel increases with the nitrogen pressure. When the nitrogen pressure is 0.08 MPa, the removal rates of T[O] and the inclusions are 89.2% and 87.4%, respectively. Theoretical analysis shows that the nucleation rate, number, and density of bubble in molten steel increase with pressure, the efficiency of the inclusions removal can be promoted.
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參考文獻
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