共查询到20条相似文献,搜索用时 106 毫秒
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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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Mikael PERSSON 《冶金译丛》2010,(1):25-32
在过去几十年里,连铸是铸钢过程中的主要生产工艺流程。在此工艺过程中,结晶器保护渣在结晶器和坯壳之间起到润滑作用,保证连铸过程顺利地进行,同时保证铸坯质量。结晶器保护渣粘度是确定最佳浇铸条件的关键参数。为了确定结晶器保护渣的粘度参数,早期进行了几个试验研究,工业用渣以及合成渣的成分接近于工业用结晶器保护渣。然而,随着新钢种的不断更新,需要更多的洁净钢生产工艺操作,在生产中使用的结晶器保护渣,一般观察到Al2O3含量大约为2%-4%,由于这个原因,本文对瑞典钢厂使用的结晶器保护渣粘度开始进行试验性地研究,并且同时研究了氧化铝的溶解对其产生的影响,讨论了本研究中测量结晶器保护渣粘度的工业涵义。通过旋转圆筒式方法测量了连铸生产工艺中使用的结晶器保护渣粘度。本研究采用了7种工业用结晶器保护渣,对应的7种不同化学成分,也研究了结晶器保护渣中Al2O3含量的影响。甚至加入相对较小数量的Al2O3,也会对保护渣粘度产生较大的影响,测量温度范围从1373K到1673K。 相似文献
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影响连铸板坯表面质量的内在因素很多,其中结晶器的传热和二冷区的传热过程是不可忽视的两个方面。概述了国内外用数学模型分析热流状态、分析结晶器保护渣发生的热过程,以及研究开发二冷区热交换系数模型,用于预测中间裂纹的形成的情况。 相似文献
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Mould powders impact the stability of the continuous casting process for steel at all casting speeds. The main functions of mould powder are to provide sufficient lubrication and to control the mould heat transfer between the solidifying steel shell and the copper mould. At higher casting speeds associated with thin slab casting, the role of the mould powder is even more important. Actual casting speeds for the thin slab caster at Corus IJmuiden are between 5.4 and 6 m/min; the production level is around 1.3 Mt/year (coils). It has been decided to increase the production of this caster to a level of 1.8 Mt/year (coils). In order to meet this demand, the steel in mould time has to be increased to approximately 85% and the maximum casting speed will be increased to 8 m/min. A collaborative project between Sumitomo Metal Industries (SMI) and Corus IJmuiden was initiated to develop mould powders which facilitate casting speeds up to 8 m/min at the thin slab caster. Main subjects of this project are: mould powder design, characterisation of mould powder and mould slag, trials at the pilot caster of Sumitomo and finally plant trials at the thin slab caster of Corus. A special point of attention is the condition to use mould powder as a granulated material at the thin slab caster. As a consequence, the characterisation work focussed on the choice of raw materials and on the corresponding phase relations at elevated temperatures. Typical of the developed mould powders are so‐called mild cooling properties which will result in a controlled mould heat transfer during casting. In this paper, several aspects of this joint project between Sumitomo and Corus will be described. 相似文献
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Mould powders play an important role in the stability of the continuous casting process of steel. The main functions of mould slag (i.e. molten powder) are to provide sufficient lubrication and to control the heat transfer between the developing steel shell and the mould. Sufficient lubrication requires an undisturbed melting of mould powders and uniform infiltration of mould slag. Based on the casting practice in IJmuiden, it is found that these demands become even more important for the applied high casting speeds in thin slab casting at 5 to 6 m/min. At Corus RD&T, mould powders were characterised by X‐ray diffraction and subsequent fully quantitative Rietveld analysis. Additionally, the melting of mould powders has been studied in‐situ using high‐temperature X‐ray diffraction, to gain crucial knowledge about melting relations. Slag rims obtained from the thin slab caster mould were characterised using extended microscopic techniques in order to describe the mechanisms of rim formation and growth. Finally, slag films obtained after casting were characterised. As a result, not only the melting process of mould powder, but also the mechanism of formation and growth of slag rims is much better understood. This knowledge will be applied to define the demands on the composition and properties of mould powder for even higher casting speeds. 相似文献
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根据包钢圆坯连铸机的浇铸条件,研制出一种圆坯结晶器保护渣。工业试验结果表明;研制的渣能够替代进口产品,满足圆坯Φ230-350mm断面连铸生产工艺要求。 相似文献
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Jeferson L. Klug Daniel R. Silva Suzana L. Freitas Márcia M. S. M. Pereira Nestor C. Heck Antônio C. F. Vilela Detlef Jung 《国际钢铁研究》2012,83(8):791-799
There is a clear trend in industry to eliminate fluorine from metallurgical slags. Regarding the continuous casting process, fluorine in mould powders is undesirable due to the following reasons: (i) evolves easily from slags producing health‐injurious gaseous substances like hydrofluoric acid, (ii) creates problems for storage and utilization of solid waste, and (iii) causes machinery corrosion. A collaboration among universities, mould powder supplier, and steel producer was established, aiming for the development of a new F‐free mould powder for billet casting. Firstly, technological parameters for a particular composition were determined: melting characteristics, viscosity, melting behavior, and crystallization tendency. Afterwards, industrial trials were performed in a Brazilian steelworks, doing some evaluations during the continuous casting process, such as ΔT between water cooling inlet and outlet, slag pool thickness, melting performance, powder consumption, Al2O3 pick‐up, and effect on SEN erosion. Comparable surface quality for the billets was obtained when using the F‐free mould powder, since the amount of scrap produced during the rolling process was not critical. 相似文献
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The melting behaviour of mould powder during continuous casting is an important consideration with respect to caster performance, production rate and steel quality. In this experimental study the effect of different carbonaceous materials on the melting characteristics of mould powders was evaluated. Using X‐ray diffraction, different types of carbon were quantitatively characterized in terms of their internal structure and reactivity experiments were conducted to investigate potential relationships between the structural morphology of carbons and their reactivity. High temperature microscopy and drip test experiments were then used to investigate the melting behaviour of mould powders containing different carbonaceous materials. From the results obtained, correlations were established between the structural factors, chemical reactivity and melting behaviour. 相似文献
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《Canadian Metallurgical Quarterly》2013,52(4):467-476
The melting behaviour of mould powder during continuous casting is an important consideration with respect to caster performance, production rate and steel quality. Two important factors, powder composition and carbon addition, are critical to control the properties and melting behaviour of the mould flux. In this study, the effect of different carbonaceous materials on the melting characteristics of mould powders was evaluated. Correlations were established between the structural factors and chemical reactivity of carbon and melting behaviour of mould flux. In addition, two examples are given of the effect of flux composition on casting performance for specific steels. A flux with reasonable basicity and additives was designed for the casting of heat-resistant steel (Incoloy 800) to reduce surface cracks. Another flux was designed for the casting of non-magnetic steel containing high aluminium by partially replacing SiO2 with Al2O3 to limit aluminium oxidation by SiO2. 相似文献