共查询到19条相似文献,搜索用时 62 毫秒
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摘要:通过水模型实验研究了上水口环形吹氩工艺下中间包和结晶器内气泡形貌,并结合数值模拟分析了透气砖位置、拉坯速度和吹氩量对中间包和结晶器内气泡尺寸、气泡迁移和中间包近液面钢液流动的影响。结果表明:上水口环形吹氩形成以塞棒为中心的圆台状气泡羽流,气泡浓度沿径向向外逐渐减少;附壁效应使得气泡羽流偏向塞棒壁面流动,增大气泡的碰撞聚并概率和近塞棒壁面的羽流上升速度,对中间包液面产生较大冲击作用;同时,部分细小气泡会随钢液进入水口及结晶器内部;增大吹氩量,中间包内环形气泡羽流中气泡数目明显增多,中间包近液面钢液上升速度增大;增大拉坯速度,环形气泡羽流的宽度和气泡数量逐渐减小,近液面速度减小;增大透气环距水口中心距离,中间包内气泡弥散度增大,环形气泡羽流宽度也随之增大,气泡羽流对中间包液面冲击作用减弱;增大吹氩量和拉坯速度、减小透气环距水口中心距离,进入结晶器的气量和气泡尺寸逐渐增大。实验条件下,透气环内外径为110mm/140mm、拉坯速度为1.2m/min时,吹氩量为4L/min较为合适。 相似文献
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以180 t双孔底吹氩钢包为研究对象,对6种钢包底吹氩模式进行数值模拟,并结合现场试验与当前采用的吹氩模式进行对比。研究发现:(1)钢液的混匀时间随吹氩量的增加而减少,吹氩量一定时,差流量吹氩模式对钢液的搅拌强于等流量吹氩模式。(2)不同的钢包底吹氩模式,渣眼形成的位置不同,渣眼面积也不同。总流量一定时,差流量吹氩模式钢液面最大流速大于等流量吹氩模式,易发生钢液卷渣。(3)差流量吹氩模式渣线处渣层厚度的波动大于等流量吹氩模式,且流量差值越大,波动越剧烈。(4)差流量吹氩模式通过“强-弱”流股的配合,进一步强化了钢包底吹氩的钢液精炼效果。工业试验表明,采取等流量吹氩模式(500 L/min—500 L/min),钢中的较大夹杂物的数目明显多于差流量吹氩模式(400 L/min—600 L/min)。 相似文献
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连铸中间包底吹氩物理模拟和工业实践 总被引:1,自引:0,他引:1
通过实验室物理模拟和工业应用实践,研究了透气砖底吹氩对本钢中间包内流体流动行为和去除钢中夹杂物行为的影响.物理模拟研究结果表明,底吹氩可以显著改善中间包内钢水的流动特征,延长钢水在中间包内的停留时间,提高中间包内钢水的混合程度,减少死区体积分率;吹气位置越靠近中间包水口侧对流体特征参数的改变效果更佳;吹氩形成的微气泡群可以显著改善中间包内流体的运动轨迹,流体运动的路线更加曲折,并且全程流动靠近液体表面.工业实践表明,底吹氩形成的“气幕挡墙”对夹杂物效果去除效果明显,与不吹氩相比,铸坯中夹杂物指数从7.33~8.98 mg/(10 kg)降低至4.21~4.33 mg/(10 kg),且大颗粒夹杂物数量明显减少,没有发现尺寸大于30~50μm的夹杂物. 相似文献
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通过现场实验,研究了中间包吹氩位置和氩气流量对钢水洁净度的影响,重点探讨了在注流区吹氩对钢水洁净度的影响.结果表明:在T型中间包注流区内进行合适流量吹氩可提高钢水洁净度,在浇铸区拐角处和塞棒附近吹氩对钢水洁净度没有明显的影响;在注流区内吹氩,合适的氩气流量为6L·min-1,与不吹氩相比,钢中总氧降低率和夹杂物的去除率均可提高10%左右,但15L·min-1的大流量吹氩将会显著增加钢中总氧和大型夹杂物数量.分析认为:注流区内大的湍流强度可将氩气泡击碎成弥散小气泡,大量小气泡在钢液中上浮,不但提高了气泡捕捉夹杂物的概率,而且增加了夹杂物之间的碰撞机会,其结果是增大了夹杂物的粒径,促进了夹杂物的上浮去除;同时,注流区离水口距离最远,在注流区吹氩,碰撞长大的夹杂物有更长的时间上浮排出.以上两个因素的共同作用,使得在注流区吹氩对去除钢水夹杂物有显著效果. 相似文献
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The water model experiments were carried out to study the bubble morphology in the tundish and mold with the process of annular argon blowing at tundish upper nozzle. The effects of the position of gas permeable brick, the casting speed and the argon flow rate on the bubble size distribution, the bubble migration behavior and the flow behavior of liquid steel near the liquid level in tundish were further investigated, coupled with the numerical simulation. The results show that with the process of annular argon blowing at tundish upper nozzle, a frustum cone shaped bubble plume can be formed around the stopper rod. The concentration of argon bubbles gradually decreases outward along the radial direction of the stopper rod. Owing to the wall attached effect, the bubble plumes float upward along the stopper rod, which can increase the collision probability between bubbles and the velocity of bubble plumes, causing a larger impact strength on the liquid level in tundish. In addition, a part of small bubbles are wrapped into the nozzle and the mold due to the drag force of liquid steel. With increasing argon flow rate, the number of bubbles in annular bubble plumes and the vertical velocity of liquid steel near the liquid level in tundish increase significantly. With increasing casting speed, the width and the bubble number of annular bubble plumes gradually decrease, leading to a decrease of the vertical velocity of liquid steel near the liquid level in tundish. Increasing the distance between the annular gas permeable brick and the center of tundish upper nozzle, the dispersion of bubbles and the width of bubble plumes increase, and the impact strength of bubbles acting on the liquid level in tundish becomes weaker. As the argon flow rate and the casting speed increase, and the distance between the gas permeable brick and the center of tundish upper nozzle decreases, the gas volume and bubble size in the mold increase. Under the experimental conditions, when the inner and outer diameters of the annular gas permeable brick are 110mm and 140mm, respectively, and the casting speed is 1.2m/min, the appropriate argon flow rate is 4L/min. 相似文献
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针对石钢60tLD-LF-VD-CC生产工艺,对4炉采用不同钢包软吹氩时间的GCr15轴承钢进行取样分析.采用金相显微镜和扫描电镜结合能谱分析,研究了4炉轴承钢中间包样品中夹杂物的尺寸分布及种类特征.结果表明,随着精炼后软吹氩时间的延长,GCr15轴承钢中全氧质量分数降低,中间包中的夹杂物平均直径减小,大于15μm的夹杂物比例也明显降低,但对夹杂物的种类没有明显影响.钢中夹杂物主要为Al_2O_3、MgO·Al_2O_3和MgO-Al_2O_3-SiO_2-CaO(CaS)夹杂物等,这与冶金热力学计算结果一致. 相似文献
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全文通过对钢包建立合理的数学模型 ,对其吹氩行为进行模拟 ,分析了不同情况下钢液温降行为 ,为减少钢液温降、降低出钢温度、合理制定钢包的温度制度提供了一定的依据 相似文献
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Bubble defect is one of the main defects of an automobile sheet.To solve this defect,the technology for nitrogen-argon mixed gas blowing on the tundish stopper is developed,the theoretical research on nitrogen absorption in the molten steel is performed,the nitrogen-argon mixed gas blowing equipment is developed and experimented in the plant.The expected effect is achieved in the industrial test,and the slab inclusion density and quality degradation ratio of the automobile sheet are significantly reduced. 相似文献
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