(東北大學(xué) 材料電磁過程研究教育部重點(diǎn)實(shí)驗室, 沈陽 110004)
摘 要: 采用低熔點(diǎn)Sn-32%Pb-52%Bi合金模擬鋼液，研究交變磁場作用下金屬熔池液面的波動和變形行為。結(jié)果表明：交變磁場會使金屬液面發(fā)生弧形變形，液面一直處于波動狀態(tài)；熔池在三相點(diǎn)附近形成匯聚撞擊的兩個回流區(qū)，導(dǎo)致液面上三相點(diǎn)附近的波動最劇烈，易造成表面卷渣；增加線圈電流強(qiáng)度，液面變形增大，波動加劇；當(dāng)熔池外壁面的磁感應(yīng)強(qiáng)度達(dá)到約50 mT時，液面的波動幅度達(dá)到約±3 mm，應(yīng)有一個合理的電流強(qiáng)度；適當(dāng)增加頻率可減小電磁力對自由表面波動的影響范圍，有利于增大彎月面變形和減小液面波動，頻率控制在30 kHz左右較適宜；液面位于線圈中心高度附近時，彎月面變形較大，液面波動較劇烈，初始液面控制在線圈高度中心有利于節(jié)能。波動規(guī)律可解釋電磁軟接觸連鑄中鑄坯表面振痕隨電流強(qiáng)度大小的變化規(guī)律。
關(guān)鍵字: Sn-Pb-Bi合金；模擬鋼液；液面變形；液面波動；連鑄；交變磁場
alternating magnetic field in mold
（Key Laboratory of Electromagnetic Processing of Materials ,
Ministry of Education, Northeastern University, Shenyang 110004, China）
Abstract:Simulating molten steel using Sn-32%Pb-52%Bi low-melting-point alloy, the metal free surface fluctuation and deformation behavior with alternating magnetic field was investigated. The results show that the meniscus becomes camber due to alternating electromagnetic field, and the free surface is keeping fluctuating. There are two recirculation flow zones near the triple-phase point where the up flow is encountered with the down flow, which enhances the fluctuation of the free surface in the vicinity of triple-phase point and tends to cause slag entrapment. On the whole free surface, the fluctuation in the vicinity of triple-phase point is the most violent. With increasing coil current intensity, the meniscus distortion is enlarged, and the fluctuation of the free surface is aggravated. When the magnetic flux density on the outer surface of the molten bath is about 50 mT, the fluctuation amplitude of free surface is about ±3 mm. The coil current intensity should be controlled in a reasonable range. With increasing frequency, the effect of electromagnetic force on the free surface fluctuation reduces. Within a proper frequency range, with increasing magnetic field frequency, it tends to increase the meniscus height and decrease the fluctuation of free surface. While the initial metal level is located at the center height of the coil, the meniscus deformation is larger and the metal free surface fluctuation is also more violent. In order to save energy, the metal level should be located at the center of the coil height. The fluctuation behavior clearly interprets the change law of billet surface oscillation marks with coil current intensity in the electromagnetic soft-contact continuous casting process.
Key words: Sn-Pb-Bi alloy; simulating molten steel; meniscus deformation; free surface fluctuation; continuous casting process; alternating magnetic field
