低密度脉冲电流对钢包中非金属夹杂物迁移行为的影响

In order to accelerate the migration and floating upward rate of inclusions in the ladle and improve their migration behavior, low density electric current pulses will be utilized in this proposal. Through high temperature static experiment and hydraulic simulation investigation, the effect of electric current pulses on the migration route of inclusions in the molten steel, flow field of molten steel, bubble behavior, and interactions between bubbles and inclusions will be systematically explored, and the coupling effect of electric current pulses, flow field of molten steel, and movement of bubble on the migration behavior of inclusions in the molten steel will also be considered. In addition, a relationship between elctric current pulses and the migration rate of inclusions will be established, and the mechanism of the migraion and floating upward of inclusions in the molten steel under the influence of electric current pulses will be clarfied. Furthermore, the law of the effect of low density electric current pulses on the migraion behavior of inclusions in the molten steel will be revealed, and a physical model of the migration and floating upward of inclusions in the molten steel under the coupling interactions of electric current pulses, flow field of molten steel, and the movement of bubble will be builded. By the accomplishment of the proposal, the physical essence of the migration and floating upward of inclusions in the molten steel under the effect of electric current pulses will be revealed, and a therorectical foundation of the controlling of the quantity and distribution of inclusions in the molten steel by the application of electric current pulses will be provided. Especially, a feasible new method to remove inclusions in the molten steel will be proposed and the application of electric current on the purification of molten steel will be enriched.

申请者拟采用低密度脉冲电流处理技术促进钢包中夹杂物的迁移上浮，改善钢液中夹杂物的迁移行为。项目采用静态高温实验和水力学模拟实验相结合的方式，分别考察脉冲电流对钢液中夹杂物迁移过程、钢液流场、气泡行为以及气泡与夹杂物间相互作用过程的影响；研究脉冲电流、钢液流场以及气泡运动耦合作用下钢液中夹杂物的迁移行为，建立脉冲电流参数与夹杂物迁移速率间的关系式，阐明脉冲电流作用下钢液中夹杂物迁移上浮的机理；揭示低密度脉冲电流对钢液中夹杂物迁移行为的影响规律，构建脉冲电流、钢液流场以及气泡运动耦合作用下钢液中夹杂物迁移上浮的物理模型。 研究结果揭示了脉冲电流作用下钢液中夹杂物迁移上浮的物理本质，为利用脉冲电流处理技术控制钢液中夹杂物的数量和分布奠定了理论基础，尤其为去除钢液中夹杂物提出一种新的可行方法，丰富了电流在钢液中的应用。

随着社会的进步和科技的发展，人们对钢铁材料性能的要求越来越高，这就需要在原有冶炼技术的基础上开发出新技术。本项目通过系统研究钢液中非金属夹杂物在低密度脉冲电流作用下的迁移行为，揭示了低密度脉冲电流对钢液中夹杂物迁移行为的影响规律，并将脉冲电流技术应用于连铸过程中控制浸入式水口堵塞，获得以下主要结论：.(1) 与未脉冲电流处理试样相比较，脉冲电流处理试样中的非金属夹杂物尺寸减小，气泡数量非常少且尺寸小；.(2) 在熔融钢液中施加脉冲电流处理时Al2O3系夹杂物和金属夹杂物聚集在负极区域，MnS夹杂物在正极附近；.(3) 在熔融钢液至固相点以上50℃（1420℃）的过程中施加脉冲电流处理时析出含钛夹杂物，而未施加脉冲电流处理试样中钛元素的偏析严重；.(4) 在熔融钢液至固相点以下60℃（1310℃）过程中施加脉冲电流处理，靠近负极附近的位置出现了较多Al2O3系的小颗粒夹杂物，且高频率脉冲电流的影响效果更加明显；.(5) 在熔融钢液至1110℃的过程中施加脉冲电流处理，在正极附近的位置出现了大量的MnS-Al2O3-SiO2的复合夹杂物，而在不施加脉冲电流处理钢样发现有鱼骨状的MnS夹杂析出；.(6) 将脉冲电流处理技术应用于防止浸入式水口堵塞的实践应用，提出钢液中的夹杂物在脉冲电流作用下通过层流层在水口内壁的附着，从而形成光滑致密夹杂物附着层。该技术的应用不仅延长了浸入式水口的使用寿命，而且提高了铸坯质量。. 综上，通过本项目的实施不仅揭示了脉冲电流作用下钢液中夹杂物迁移上浮的物理本质，为利用脉冲电流处理技术控制钢液中夹杂物的数量和分布奠定了理论基础，尤其将脉冲电流应用在连铸过程中不仅延长了浸入式水口的使用寿命，而且提高了铸坯质量，丰富了电流在钢铁工业中的应用。