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结晶器摩擦力对连铸顺行非常重要,而钢液流动行为会影响铸坯温度场和保护渣分布,可能对铸坯摩擦力产生一定的影响.利用Fluent软件建立结晶器内钢液流动、传热三维数学模型,并将温度场数据导入Ansys计算铸坯应变,然后根据铸坯-保护渣-结晶器摩擦行为数学模型讨论了渣膜润滑情况,对比了不同水口底部形状下结晶器内液态、固态和总摩擦力.结果表明:不考虑水口射流时结晶器总摩擦力比考虑水口时增大约29.4%;浸入式水口底部形状分别为凸底、平底和凹底3种情况下铸坯窄面中心温度依次降低,凝固壳厚度依次增大,固态摩擦力依次增大,总摩擦力依次增大,液态摩擦力相差较小. 相似文献
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软接触结晶器电磁连铸可以改善铸坯的表面质量,但其电磁场对拉坯阻力的影响以及拉坯阻力与铸坯表面质量间的关系仍值得研究。笔者设计并制作了悬臂梁应变仪,在小型连铸机上测定了软接触结晶器电磁连铸过程中结晶器内的拉坯阻力,并对连铸坯的表面质量进行了分析。结果表明:①在本实验条件下,随着拉坯速度的提高,无论有、无保护渣或连续的高频电磁场,拉坯阻力均增加,铸坯表面质量下降;②施加保护渣或连续的高频电磁场都能显著降低拉坯阻力,而且拉坯速度越大,拉坯阻力下降的幅度越大;③随着磁场强度的增加,拉坯阻力减小,铸坯表面质量提高。但当磁场强度达到一定程度时,拉坯阻力开始增大,相应的铸坯表面质量下降。这表明,铸坯表面质量与拉坯阻力直接相关。 相似文献
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以水平连铸圆坯连铸生产工艺为研究对象,采用Fluent数值模拟软件凝固传热模型并结合射钉试验共同研究了管坯在不同拉坯工艺条件下,结晶器内的温度场分布与凝固传热过程,并对不同拉坯参数下铸坯试样进行了检测分析。研究发现:水平连铸拉坯工艺参数:拉速V=2.13m/min,浇注温度T=1544℃,中间包过热度△T=40℃的拉坯参数下,结晶器内的温度场分布均匀稳定,铸坯质量好,产量高。研究表明,采用Fluent数值模拟软件凝固传热模型并结合射钉试验可以有效分析在不同拉坯工艺条件下水平连铸结晶器内的温度场分布及凝固传热过程,并进一步制定合理的拉坯工艺参数,降低管坯质量缺陷的发生,提高铸坯质量。 相似文献
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考察了结晶器电磁制动技术在板坯连铸过程中的应用效果,比较了电磁制动对结晶器内钢液火焰状态和温度分布的影响,结果表明:合理的制动电流可使结晶器内钢液液面波动降低、火焰均匀分布,燃烧状态达到最佳,过大和过小都不利于火焰燃烧状态和传热的均匀性;施加电磁制动可显著提高结晶器内钢液温度分布的均匀性,平均温差由10℃降低到4℃;合理使用电磁制动有利于提高保护渣渣耗且使保护渣熔化更均匀,本研究条件下的吨钢渣耗提高了0.021kg;铸坯质量检验表明,使用电磁制动可降低铸坯中氧化夹杂物含量,对于试验条件下的低碳钢全氧质量分数降低了49%。 相似文献
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将连铸过程连铸坯凝固收缩、鼓肚变形、气隙、保护渣及结晶器传热进行耦合求解,开发出了适用于165 mm×225 mm的Q235B钢矩形坯连铸过程中钢水传热凝固的计算模型,并利用该模型对拉速1.5 m/min工况下结晶器内连铸坯的传热凝固行为进行了详细计算。计算结果表明连铸坯宽面温度在气隙分布的影响下呈不均匀分布,且与现场坯壳比对研究可以发现振痕的形成分成了4个阶段,第1阶段发生在距弯月面0~0.17 m,高温区分布法向与拉坯方向垂直,法向垂直于拉坯方向的振痕形成;第2阶段发生在距弯月面0.17~0.26 m,温度分布呈现W形,法向与拉坯方向平行的振痕形成;第3阶段发生在距弯月面0.26~0.36 m,宽度方向温度进一步均匀化,法向与拉坯方向平行的振痕进一步向均匀化发展;第4阶段发生在距弯月面0.36~0.80 m,连铸坯宽面宽度方向的温度分布趋于稳定,振痕也趋于稳定。现场漏钢坯壳的振痕形貌图与计算的温度分布图相似,计算模型可以用来解释该工况下连铸坯的传热凝固行为。现场加大结晶器锥度和调整结晶器铜管刚度,漏钢率和铸坯鼓肚及脱方超标比例显著下降。 相似文献
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Lubrication and friction between the mould and strand are strongly influenced by mould oscillation, and play an important role in slab quality and operating safety during continuous casting processes. Investigation of mould oscillation is therefore essential for getting a better online control of the mould processes. A feasible approach for the development and optimization of mould oscillation was put forward, which combined online measurement of mould friction, design of negative oscillating parameters and evaluation for powder consumption. Three different control models including sinusoidal and non-sinusoidal oscillation for mould oscillations were developed to investigate and evaluate the effects of oscillation on mould friction and powder lubrication. For the purpose of investigating mould friction between mould and strand, online measurement was carried out on a slab continuous caster equipped with a hydraulic oscillator. Also the comparison of the mould friction in sinusoidal and non-sinusoidal mould oscillation was made for subsequent analysis. The industrial experiment result shows that the combination of inverse control model and non-sinusoidal oscillation mode will contribute to the proper powder consumption, leading to a suitable effect of friction force on strand surface, especially for high speed continuous casting. The proposed method provides reliable basis for guiding and optimizing mould oscillation among control models, sinusoidal oscillation and non-sinusoidal oscillation. 相似文献
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《钢铁冶炼》2013,40(2):112-118
AbstractIt is very important to obtain reliable lubrication from casting powder both at the meniscus and in the gap between strand and mould as it affects slab surface quality and caster productivity. With knowledge of mould friction, a quantitative insight into the behaviour of powder during caster operation is possible. In the present research, the friction was studied based on a slab continuous caster equipped with hydraulic oscillators. The effects of mould oscillation and the abrupt change of casting speed on mould friction force were evaluated, and the characteristics of lubrication behaviour in a casting sequence were investigated. In particular, a comparison between the mould friction force between sinusoidal oscillation mode and non-sinusoidal oscillation mode was made. Finally, the characteristics of friction before a breakout are discussed. The experimental and analytical results may contribute to the development of mould friction online measurement and more clearly learn the lubrication behaviour in different conditions. 相似文献
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根据攀钢2^#板坯连铸的工艺特点,在分析了高速连铸对保护渣性能要求的基础上,研究开发出了适应高拉速浇注的连铸保护渣,工业试验结果表明,研究开发的YC—DT高拉速用连铸保护渣,在拉速≥1.70m/min时不仅结晶器内熔化状况良好,而且保护渣消耗量适宜,所浇铸坯表面质量良好,能够满足攀钢2^#板坯高速浇注的需求。 相似文献
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In continuous casting, the friction forces in the mould reflect the lubrication between the mould and slab, moreover, they affect the slab surface quality and caster productivity. In the present research the friction force is calculated by measuring the difference of working forces during HOT and COLD tests, which are carried out on the slab continuous caster equipped with hydraulic oscillators. Through analysing the mould friction using the Fast Fourier Transformation (FFT) method, the effects of mould oscillation mode and casting speed on the mould friction force are evaluated. The characteristics of the friction signal in the frequency domain are also investigated. Especially, the characteristics of friction force fluctuations before breakouts are discussed. The experimental and analytical results may contribute to more clearly understand the transient lubrication behaviour not only in the time domain but also in the frequency domain, which is also useful for the application of FFT in data analysis of mould processes. 相似文献
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The interaction of the strand shell surface and mold copper plates has significant effects on the slab surface quality and casting productivity. This article focuses on developing a reliable approach to measure the transient friction force between the slab and the mold for the purpose of the investigation of lubrication and friction behavior inside a mold. This method is presented to monitor transient mold frictions for the slab continuous caster equipped with hydraulic oscillators. A mathematical model is also developed to calculate the empty working force of the no casting state, and a new algorithm, based on the particle swarm optimization, is proposed to predict the dynamic characteristic parameters of mold oscillation. The results have shown that the method has a sufficient sensitivity to variation, especially to the periodical variation of the mold friction, and it has been identified that the transient mold friction can be used as an effective index with regard to detecting mold oscillation and optimizing the casting parameters for process control. It may lay the practical foundation for the online detection of powder lubrication and the visualization of the continuous-casting mold process. 相似文献
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宽厚板连铸结晶器摩擦行为在线测试与分析 总被引:1,自引:0,他引:1
结晶器/铸坯摩擦行为是影响并决定铸坯表面质量的重要因素。以宽厚板坯连铸结晶器为对象,在线检测基于液压振动装置的结晶器/铸坯摩擦力,测试和分析浇铸温度、铸坯断面、拉速与结晶器振动方式等主要工艺参数对摩擦力的影响,为考察和调控结晶器/铸坯摩擦行为提供试验基础。相同工艺条件下,摩擦力随浇铸温度的升高而降低,随铸坯断面尺寸的增加而增大。正弦、非正弦振动方式与拉速-振频、振幅振动控制模型的合理匹配,能够显著改善高拉速下的结晶器/铸坯摩擦行为,结晶器振动工艺的开发和优化对于充分发挥液压振动装置设备潜力,稳定高拉速下铸坯表面质量具有积极意义。 相似文献