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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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薄板坯连铸带液芯轻压下过程的力学计算 总被引:2,自引:0,他引:2
为了给实际薄板坯连铸带液芯轻压下的设备设计和工艺设计提供依据,对薄板坯连铸带液芯轻压下过程中的铸坯变形抗力、拉坯阻力及其变化特性进行了理论计算。分析比较了不同轻压下设备(二冷支撑段辊列)条件下,连铸及轻压下过程的工艺参数对它们的影响。结果表明,在二冷支撑段辊列运动挤压铸坯阶段,最后一对支撑辊的移动量、挤压速度、拉坯速度、支撑辊间距离、辊径和对数以及坯壳温度对铸坯变形抗力和拉坯阻力有很大影响;而在二冷支撑段辊列稳定挤压铸坯阶段,只有总轻压下变形量及坯壳厚度影响较大。 相似文献
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边直裂缺陷控制装备在使用过程中会使铸机在拉坯方向产生额外的拉坯阻力,造成电机电流增大,影响铸机正常生产,严重的甚至会产生"滞坯"风险。因此,建立了边直裂缺陷控制装备模型,对该装备的运行过程进行了数值模拟,研究了压制不同宽度二次倒角与所产生的额外拉坯阻力和所需压制力的对应关系,并以此为依据开展工业试验,研究了拉坯阻力增大对电机电流实际变化的影响。同时计算了不同压力条件下的拉坯力,对比分析了电机电流的变化。研究表明:所产生的额外拉坯阻力的大小与压制的二次倒角宽度呈正比,在满足工艺效果的前提下,压制最大二次倒角宽度时的电机实际电流小于额定电流,说明其产生的额外拉坯阻力不会对该钢厂铸机正常运行产生影响。 相似文献
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分析了可分式拉坯辊装置在水平连铸拉坯生产中存在的问题,介绍了整体式拉坯辊装置的研制和使用情况,使用水平连铸机整体式拉坯辊装置具有结构轻便简单,安装更换方便,使用寿命长。能有效提高铸坯质量,降低成本及明显提高水平连铸机生产效率等优点。 相似文献
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简要分析了可分式拉坯辊装置在水平连铸拉坯生产中存在的问题,简要介绍了整体式拉坯辊装置的研制和使用情况,使用水平连铸机整体式拉坯辊装置具有结构轻便简单,安装更换方便,使用寿命长,能有效提高铸坯质量,降低成本及明显提高水平连铸机生产效率等优点。 相似文献
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分析了可分式拉坯辊装置在水平连铸拉坯生产中存在的问题;介绍了整体式拉坯辊装置的研制和使用情况。整体式拉坯辊装置具有结构轻便简单.安装更换方便,使用寿命长,能有效提高铸坯质量.降低成本及明显提高水平连铸机生产效率等优点。 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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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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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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《钢铁冶炼》2013,40(5):353-359
AbstractThis paper is the first of a series of two describing online monitoring of the continuous casting machine and the abnormal transient phenomena observed. The present paper, Part 1, pays attention to assessment of the friction between the billet and mould based upon the cam rod force and the electric current intensity of the mould oscillation motor. Information relating to casting parameters before 58 breakouts has been obtained with a monitoring computing program. Almost 40% of the breakouts could have been forecast through assessment of the billet-mould friction force before the breakouts. Transient phenomena in the withdrawal machine have been detected. The jerking of the strand is related to high billet-mould friction; however, other parameters such as the billet cutoff unit and roller bed design also have some effects on this transient phenomenon. Some mechanisms influencing the jerking of the strand are proposed. 相似文献
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《钢铁冶炼》2013,40(3):164-168
AbstractIn casting the control model relation between casting speed and frequency plays an important role in the optimisation of process parameters and the improvement of lubrication condition. The mould friction between mould and strand can directly describe the powder lubrication situation in a mould. In the present research, based on the slab continuous caster equipped with hydraulic oscillators, the transient friction forces were obtained by the differences between the monitored driving forces of casting and the calculated driving forces of no casting at same oscillation parameters. According to the trends of friction force with different control models, the characteristics and disadvantages of the traditional positive control model, and the improved positive control model and the inverse control model are discussed. This experimental study contributes to studying the frictional behaviour in mould under different control models, as well as selecting reasonable control model for high speed continuous casing. 相似文献
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外加液态保护渣可以提高铸坯质量和可浇性。在某厂板坯连铸机上,分别采用液态保护渣和固态保护渣进行多钢种浇注试验,对比液态保护渣和固态保护渣消耗量、结晶器温度分布、拉坯摩擦力及铸坯质量,并对液态保护渣的应用前景进行展望。结果显示,液态保护渣比固态保护渣消耗量增加60%左右,结晶器温度分布更均匀,连铸拉坯摩擦力降低约15%,铸坯质量有所提高。这说明在连铸过程中,液态保护渣使结晶器和铸坯间传热更均匀;液态保护渣润滑效果更好,可以提高铸坯质量。同时,有望不添加F-、Na+等有害离子,改善环保问题。 相似文献
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《钢铁冶炼》2013,40(5):360-368
AbstractThis paper is the second of a series of two describing abnormal transient phenomena observed during online monitoring of a billet continuous casting machine. Special attention is paid in Part 2 to in mould solidification. A mould heat flux drift phenomenon (HFD) has been detected, but only for mould powder basicities larger than 0·8. The HFD is related to a decrease of the heat flux in the lower part of the mould and an increase in both the billet-mould friction force and mould thermocouple variability. Results of tests changing the mould powder grade during casting have provided help in explaining the HFD. The probable reason for the HFD is crystallisation of the glassy slag layer. The heat flux ratio parameter (HFR), defined as the ratio between the heat flux in the lower part of the mould and the heat flux in the upper part of the mould, has proved to be a good tool for judging the casting performance of a mould powder. 相似文献