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传统保护渣成分中含有氟化物,易导致连铸过程中环境污染、设备腐蚀等问题。选用合适的助熔剂替代氟化物获得结晶性能优良的无氟保护渣,是目前连铸生产实现绿色高效化的关键。本文基于结晶温度、结晶率和结晶矿相三个方面,总结了近几年国内外与无氟环保型保护渣结晶性能有关的研究现状,无氟保护渣的化学成分对其结晶性能的影响规律,提出了无氟环保型保护渣未来的研究方向和目标,即探寻无氟保护渣中可以代替枪晶石的主晶相以满足对控制传热的需求,为开发适用于高效绿色连铸生产要求的无氟保护渣提供理论依据。 相似文献
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针对攀钢连铸 Q2 35 G等包晶钢生产中出现的铸坯表面裂纹问题 ,在调查分析裂纹特征及其产生原因的基础上 ,发现保护渣传热过强和保护渣流入不均是诱发角横裂产生的主要原因。通过对保护渣结晶特性的研究 ,开发出了低碱度 (Ca O/ Si O2 <1.0 )、高结晶率的新型包晶钢用连铸保护渣。工业试验表明 ,研制的保护渣具有良好的使用效果 ,所浇铸坯表面质量优良 ,铸坯裂纹较少 ,表面角横裂发生率降低到 4 .19% ,纵裂发生率为 3.4 2 % ,且保护渣润滑作用良好 ,未发生漏钢事故。 相似文献
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During the continuous casting of high‐Al steel, the dynamic reduction of silica‐based mould fluxes by the aluminium in the steel leads to changes in their composition and physical properties. The alumina‐based mould flux has been suggested as an alternative to alleviate this reduction problem. However, until now, the smooth running of high‐Al steel continuous casting has been impeded by the lack of systematic investigation of properties of this slag. In this paper, the effects of typical components on the properties of alumina‐based mould fluxes are discussed. The experimental results show that: (a) an increase in F? can reduce the viscosity while increasing the melting and break temperatures; (b) with increasing Li2O, the viscosity, melting temperature, and break temperature first decrease and then increase; (c) with the addition of BaO, the viscosity, melting temperature, and break temperature remain at a low level, while a further increase in BaO causes a decrease in viscosity, an increase in melting temperature, and the stabilization of the break temperature; (d) BaO is favorable to stabilize the properties of mould fluxes for the dissolution of additional Al2O3; (e) the crystalline phases of the mould fluxes mainly contain 12CaO · 7Al2O3 and 11CaO · 7Al2O3 · CaF2, and 12CaO · 7Al2O3 has great potential as a substitute for cuspidine. 相似文献
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对攀钢Q235G钢连铸坯出现的角横裂缺陷进行了调查分析,在此基础上确定了连铸保护渣是引起角横裂的主要原因。并对保护渣的配方进行了改进,通过试验,研制出了适合攀钢普碳包晶钢用的连铸保护渣,有效地控制了Q235G钢连铸坯角的横裂缺陷。 相似文献
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Inviewofheattransfer ,theroleofmouldincontinuouscastingcanneverbeoverstatedasitcon trolsboththebilletqualityand productivityofacastertoagreatextent .Inthisstudy ,AtlasSteelwaschosenasthelocationforaplanttrialbecauseverylittledataareavailableonheattransfe… 相似文献
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《钢铁冶炼》2013,40(8):593-598
AbstractDuring the continuous casting of medium carbon steel slabs, stable liquid slag film performance is necessary to ensure that the process runs smoothly. In this paper, the effects of mould flux crystallisation behaviour on the properties of leftover liquid slag films were examined. First, the compositions of the leftover liquid slags of high fluorine, CaO–SiO2–TiO2 and CaO–SiO2–Na2O based mould fluxes after a single crystalline phase was separated were calculated. Then, the viscosity, melting temperature, break temperature and degree of crystallisation of each leftover liquid flux were measured. The results revealed that the properties of leftover liquid slag films of CaO–SiO2–TiO2 and CaO–SiO2–Na2O based mould fluxes are not as stable as those of high fluorine films after crystallisation. This paper provides a new method for developing fluorine free mould fluxes and for determining the most suitable type of crystalline phase that should be utilised in the continuous casting of medium carbon steel slabs. 相似文献
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《钢铁冶炼》2013,40(3):210-215
AbstractDuring casting of titanium stabilised stainless steel, a gradual increase in TiO2 content in the molten mould slag from absorption of TiO2 inclusions causes changes in properties of the mould flux, such as viscosity, solidification temperature and crystallisation behaviour. To simulate this effect mould fluxes were prepared with SiO2 being substituted with 5 and 10%TiO2 and viscosity and crystallisation behaviour studied. Experimental results indicate that the substitution of SiO2 with TiO2 leads to suppression of crystallisation of cuspidine and formation of perovskite in glass quenched from mould fluxes. The crystallisation tendency is reduced by the introduction of TiO2. The high temperature viscosity of mould fluxes shows a decrease with increasing TiO2. At lower temperature, the viscosity of mould fluxes with 10%TiO2 is greater than that of TiO2 free slag, which could be attributed to precipitation of solid particles. 相似文献
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氟含量过高的连铸保护渣不仅加剧伸入式水口的侵蚀,而且对连铸操作环境带来危害,为了降低保护渣中过高的氟含量,需要开发低氟或无氟保护渣。为避免保护渣中氟含量降低后性能指标的恶化,需要寻求氟化物的替代组分以协调保护渣各项冶金功能的正常发挥。为此,以高氟保护渣为参照点,设计了4组低氟连铸结晶器保护渣渣样。通过检测这些渣样的熔点、粘度、转折温度、结晶温度和结晶率,分析和比较实验数据发现,在不同碱度下,B2O3、Li2O、Cr2O3、TiO2均能部分替代渣中的CaF2,获得CaF2质量分数为45%的低氟保护渣。CeO2不能作为保护渣中CaF2的替代组分。 相似文献
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通过热丝法得出保护渣连续冷却转变(CCT)和时间-温度转变(TTT)曲线,并用偏光显微分析和X-射线衍射分析方法研究了萤石含量(8%~16%)对碱度1.0的薄板坯连铸结晶器保护渣结晶性能的影响。结果表明,萤石含量每增加2%,保护渣的临界冷却速度平均增加2.5℃;同一冷却速度下,随保护渣中萤石含量的增加,结晶温度升高,结晶率增大,有利于提高界面热阻,控制渣膜传热,减少铸坯表面裂纹产生;因萤石含量超过14%时,渣膜中大量生成结晶矿物枪晶石,对连铸润滑要求较高的钢种,应控制萤石含量≤14%。 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