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钢中洁净度对车轮的各项性能技术指标有着重要影响,本文通过分析120t顶底复吹转炉-LF炉-VD炉-圆坯连铸工艺流程生产车轮钢的洁净度控制技术,并在实践中应用,取得了很好的效果,使得钢水的全氧在LF炉下降了51.7%,铸坯的中的全氧达到了15.3ppm,铸坯内部铸态组织均匀。 相似文献
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从二氧化碳在钢铁冶金流程的资源化应用出发,介绍了近年来二氧化碳在烧结、高炉、转炉、电炉、炉外精炼、连铸和冶炼不锈钢等流程的应用研究现状和发展情况。结合国内外应用研究现状和本课题组的研究情况,分析了二氧化碳在钢铁冶金各流程应用的可行性和冶金效果。主要介绍的新工艺有烟气循环烧结、高炉风口喷吹CO_2及CO_2作为高炉喷煤载气、转炉顶底吹CO_2、LF炉和电弧炉底吹CO_2、CO_2作为连铸保护气、CO_2用于冶炼不锈钢和循环CO_2燃烧。CO_2在钢铁冶金各流程的应用,合计使用量有望达到吨钢100kg,应用前景非常广阔。 相似文献
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介绍了双机架炉卷轧机的两种不同布置形式;分析比较了其优缺点;提出了在不同的生产工艺条件下两种布置形式的适用范围:分开式布置可满足难变形钢种在粗轧开坯和精轧阶段保证产品质量的不同要求,适用于大量生产不锈钢和特殊合金钢等产品的炉卷轧机;串列式布置形式可节省工程投资,有利于薄规格产品轧制,适用于生产碳钢和低合金钢为主的炉卷轧机。为有意建设炉卷轧机的厂家提供了一定的参考。 相似文献
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将神经网络和模糊数学理论相结合,建立了一种新型的炉况预报模型,利用模糊神经网络的并行处理特性进行模糊推理。模糊神经网络的并行数学计算过程取代了专家系统中传统的参数处理,具有更高的推理效率;且神经网络的学习能力实现了隶属函数和模糊规则的自学习,从而满足了高炉专家系统知识库的动态特征,有效提高了炉况预报模型的自适应能力。最后,应用莱钢1号高炉在线采集的数据动态模拟了高炉炉况的变化趋势。 相似文献
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根据LF炉生产、工艺、设备的特点,建立了适合柳钢实际的LF炉生产模式;对LF炉的生产设备进行了整改,使得其更好的服务于生产;为了能够更好的实现LF炉的升温、脱氧、去夹杂的功能,对LF炉的生产工艺进行了优化。 相似文献
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110 t EBT EAF-LF-RH-CC工艺生产无缝管钢12MnV的脱硫分析 总被引:1,自引:0,他引:1
通过LF加石灰,控制LF末期铝含量,RH过程喷80CaO-20CaF2粉,RH终点喂铝线,RH结束后喂硅钙线等操作生产≤0.003%S的12MnV钢。根据脱硫数据表明,在110 t EAF-LF-RH-CC流程中LF平均脱硫率达88%,RH平均脱硫率不足30%;铝脱氧钢的冶炼过程中,在不喂铝丝的情况下,随S含量降低,钢中Al含量降低;在RH前钢中应有足够的Al脱除钢中的氧,以利于RH脱硫。 相似文献
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分析了鞍钢1700ASP线LF精炼工序成本的构成,指出降低精炼工序成本关键在于降低渣料消耗和电能、电极消耗.通过优化渣料配比和用量,采用降低钢水传搁时间、减少了周转罐投入数量、制定合理的加热制度和加强操作等措施,缩短了加热时间,渣料消耗降低了3 kg/t钢,电能消耗减低了3.01 kWh/t钢,电极消耗降低了0.04 kg/t钢,LF精炼工序成本降低了3.82元/t钢. 相似文献
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某炼钢厂LF炉所用的SVC装置发生PT高压保险熔断、避雷器频频动作、电缆头放炮等异常运行情况。对这一现象进行了深入分析,认为是由于FC滤波支路失谐度过大造成的,并提出了相应的对策和建议,以保证SVC装置的安全可靠性。 相似文献
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阐述在一炼钢条件下生产高碳钢时浇铸温度的控制措施。通过改善钢包、中包的保温效果,并采用合理的LF炉温度控制模式,可以使高碳钢在进行低拉速浇铸时获得稳定且较低的过热度,从而有效降低铸坯碳偏析。 相似文献
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Anthrax lethal toxin is a complex of protective antigen (PA, 735 amino acids) and lethal factor (LF, 776 amino acids) that lyses certain eukaryotic cells. LF interacts with PA to gain access to the cytosol to assert its toxicity. The internalization of LF requires that PA bind to a specific membrane receptor and be cleaved by a cell-surface protease (probably furin), so as to expose a site on PA to which LF binds with high affinity. To localize LF functional domains, amino, carboxyl, and internal deletions of LF were made. Toxicity was eliminated by deletion of 40 and 47 residues from the amino and carboxyl termini, respectively. Similarly, deleting the first of the four imperfect repeats of 19 amino acids located at residues 308-383 made LF non-toxic, showing that this region is also essential for activity. To identify the minimum region of LF which is required for binding to PA, varying amino-terminal portions of LF were fused to the ADP-ribosylation domain of Pseudomonas exotoxin A. Fusion proteins containing residues 1-254 of LF were toxic when administered with PA, while those having only residues 1-198 of LF were inactive, showing that the PA-binding domain of LF lies within residues 1-254. 相似文献
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VI Gushin VA Efimov TM Smirnova AG Vinokhodova N Kanas 《Canadian Metallurgical Quarterly》1998,69(6):556-561
BACKGROUND: Short-term variability of RR interval and blood pressure occurs predominantly at low frequency (LF; approximately 0.1 Hz) and high frequency (approximately 0.25 Hz). The arterial baroreflex is thought to be the predominant determinant of the LF component of RR variability. Patients with severe congestive heart failure (CHF) have an attenuated or absent LF oscillation in RR variability. The left ventricular assist device (LVAD) offers a unique possibility for analysis of spectral oscillations in RR interval independent of any effects of blood pressure that influence these oscillations via the baroreflex. METHODS AND RESULTS: We performed spectral analysis of RR, blood pressure, and respiration in 2 patients with CHF before and after LVAD implantation. LF components of the RR-interval and blood pressure variability were absent in both CHF patients before LVAD implantation. After LVAD implantation, spectral analysis of the RR interval showed restoration of a clear and predominant LF oscillation in the native hearts of both patients, with no such oscillation evident in the blood pressure profile. CONCLUSIONS: During total circulatory support with the LVAD, the LF oscillation in RR interval of the native heart, absent in CHF, is restored. This LF oscillation in RR interval occurs in the absence of LF oscillations in blood pressure and thus is unlikely to be explained by baroreflex mechanisms. Hence, the absence of LF oscillation in the RR interval in CHF is functional and is reversible by LVAD circulation. The presence of a predominant LF oscillation in RR interval independent of any oscillation in blood pressure suggests that the LF oscillation is a fundamental property of central autonomic outflow. 相似文献