共查询到19条相似文献,搜索用时 127 毫秒
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针对攀钢IF钢RH处理过程终点碳含量偏高及不稳定的问题,对IF钢生产工艺过程进行了跟踪调查,通过对转炉终点、过程钢液氧活度、过程钢包渣成分和氧化性、脱碳处理时间等工艺过程的优化控制,进行了RH处理IF钢工艺优化工业试验研究。结果表明,RH处理IF钢出站钢液碳含量的波动范围小。增加碳粉加入量,脱碳后钢液氧活度控制在121×10-6~318×10-6,平均为230.1×10-6,较原工艺降低了约120×10-6,钢的纯净度有所改善。采用高碱度精炼渣调渣剂调整钢包渣成分,RH处理过程钢包渣中CaO含量提高,Al2O3含量下降,RH插入管在处理过程的粘渣得到明显缓解。 相似文献
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利用水模型与数值模拟相结合的方法,对Ruhrstahl-Heraeus(RH)精炼过程中的多相流体流动及混匀现象进行模拟研究。根据相似原理建立与实际210 t RH精炼装置几何相似比为1:5的水模型,采用粒子图像测速(PIV)技术获取水模型中心截面处流场分布。数值模拟采用多相流模型(VOF)和离散相模型(DPM)相耦合的计算方法,湍流模型分别选用k-e模型和大涡模拟(LES)模型。对比测量值与计算值,结果表明2种湍流模型均能较好地预测RH内流场分布;而采用LES模拟能够获得RH内瞬态的速度分布及漩涡的产生和耗散过程。测量并计算了水模型钢包内整体的混匀时间分布,结果表明上升管附近区域的混匀时间大于下降管附近区域的混匀时间。开发了气泡膨胀的数学模型,并将其用于钢液-氩气体系的模拟计算,结果表明气泡膨胀过程对钢液流动的影响显著。 相似文献
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本文根据电工钢、搪瓷板等产品含碳量<0.01%的要求,介绍了转炉生产极低碳钢的工艺技术。主要是利用炉后RH装置进行真空脱碳的技术,包括辅助浸渍管法,强化包内钢液搅拌法,增大环流量法和增加环流量的气密封法等,最后对宝钢RH装置的改造提出了建议。 相似文献
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研究了不同水韧条件下ZGMn13Cr2钢的脱碳行为,分析了实际脱碳深度与理论计算之间的关系,并对传统的计算模型进行了修正。结果表明,水韧处理加热温度越高,保温时间越长,脱碳越严重。当加热温度为1000 ℃时,实际脱碳深度与理论脱碳深度相似;加热温度为1050 ℃和1100 ℃时,由于氧化反应的加剧以及碳化物的作用,实际脱碳深度大于理论脱碳深度,传统的计算模型不再适用,采用修正的计算模型能对ZGMn13Cr2钢水韧处理中的脱碳深度起到一定的预测作用。 相似文献
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Vasileios Katranidis Sai Gu David C. Cox Mark J. Whiting Spyros Kamnis 《Journal of Thermal Spray Technology》2018,27(5):898-908
The thermal dissolution and decarburization of WC-based powders that occur in various spray processes are a widely studied phenomenon, and mechanisms that describe its development have been proposed. However, the exact formation mechanism of decarburization products such as metallic W is not yet established. A WC-17Co coating is sprayed intentionally at an exceedingly long spray distance to exaggerate the decarburization effects. Progressive xenon plasma ion milling of the examined surface has revealed microstructural features that would have been smeared away by conventional polishing. Serial sectioning provided insights on the three-dimensional structure of the decarburization products. Metallic W has been found to form a shell around small splats that did not deform significantly upon impact, suggesting that its crystallization occurs during the in-flight stage of the particles. W2C crystals are more prominent on WC faces that are in close proximity with splat boundaries indicating an accelerated decarburization in such sites. Porosity can be clearly categorized in imperfect intersplat contact and oxidation-generated gases via its shape. 相似文献
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Nanostructured WC-12Co coatings were deposited by high velocity oxy-fuel (HVOF) spraying with an agglomerated powder. The effect of flame conditions on the microstructure of the nanostructured coatings was investigated. The wear properties of the coatings were characterized using a dry rubber-wheel wear test. The results show that the nanostructured WC-Co coatings consist of WC, W2C, W and an amorphous binder phase. The microstructure of the coating is significantly influenced by the ratio of oxygen flow to fuel flow. Under the lower ratio of oxygen/fuel flow, the nanostructured coating presents a relative dense microstructure and severe decarburization of WC phase occurs during spraying. With increasing ratio of oxygen/fuel flow, the bonding of WC particles in the coating becomes loose resulting from the original structure of feedstock and the decarburization of WC becomes less owing to limited heating to the powder. Both the decarburization of WC particles in spraying and the bonding among WC particles in the coatings affect the wear performance. The examination of the worn surfaces of the nanostructured coatings reveals that the dominant wear mechanisms would be spalling from the interface of WCCo splats when spray particles undergo a limited melting. While the melting state of the spray particles is improved,the dominant wear mechanisms become the plastic deformation and plowing of the matrix and spalling of WC particles from the matrix. 相似文献
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Qun Wang Jing Xiang Genyu Chen Yingliang Cheng Xinqi Zhao Shiqi Zhang 《Journal of Materials Processing Technology》2013,213(10):1653-1660
Five WC–12Co coatings were deposited by a high velocity oxy-fuel (HVOF) system using constant oxygen flow and varying propylene flow. The phase composition, microstructure, as well as abrasive and sliding wear performance of the as-sprayed coatings were investigated. The degree of tungsten carbide (WC) decarburization in the as-sprayed coatings increases while the coating porosity decreases with the increase of the propylene flow. The coating hardness, fracture toughness, resistance to abrasive and sliding wear increases with the increase of the propylene flow, reaches maximum and then decreases. At the low flow of the propylene, relatively loose coating microstructure is formed, which leads to fracturing and pulling off the WC particles during abrasive and sliding wear process. Herewith, at the high flow of the propylene, the high degree of the WC decarburization and high brittleness of the coating leads to micro-cutting during abrasive wear as well as to cracking and delamination of the coating in the sliding wear process. 相似文献
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介绍了钢的脱碳产生机理和类型,国内外脱碳层深度测定方法标准,国家标准的变迁历程,研析和比较各种测定方法原理、特点和差异,介绍典型钢种的金相测定方法,提出规范有效脱碳层的测定方法,解决轴承钢、高速钢和钢轨用钢的脱碳层测定难题,有助于理解实施国内外脱碳层测定方法标准,方便国际钢铁贸易交流,推动钢的脱碳层控制和测试技术的发展与进步。 相似文献
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为解决爆炸喷涂过程中WC颗粒由于高温导致的脱碳问题,本文设计了一种带有拉瓦尔喷管的爆炸喷涂装置,利用该装置进行了爆炸喷涂WC涂层的理论和试验研究。基于等熵流的数值计算结果表明,喷管可以有效降低载气的温度,并可将WC颗粒加速至1000m/s以上。利用压力传感器测试了喷管入口和出口处的压力,计算了气流马赫数。在喷管出口处采用激光遮挡法测试了粒子的速度,测试结果与理论计算结果具有较好的一致性。采用扫描电镜、金相显微镜和XRD对碳化钨颗粒、涂层进行了表征,结果表明喷管的使用可以有效避免脱碳现象。该研究为解决爆炸喷涂碳化钨过程中的脱碳问题提供了一种新思路。 相似文献
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Effects of non-metallic inclusions on the initiation of pitting corrosion in 11% Cr ferritic stainless steel examined by micro-droplet cell 总被引:1,自引:0,他引:1
This paper explores the effects of non-metallic inclusions (NMIs) on the initiation of pitting corrosion in type 409L stainless steels refined by the argon oxygen decarburization (AOD) and vacuum oxygen decarburization (VOD) processes. The dominant NMIs in the AOD and VOD samples were (Ti, Ca)-oxides and Ti-nitrides, respectively. In-situ electrochemical noise (EN) and micro-electrochemical analyses were conducted to investigate quantitatively the inherent effects of the NMIs on the pitting corrosion of the alloys. Pitting corrosion was initiated mostly around the (Ti, Ca)-oxides in the AOD samples, while little such corrosion occurred around the Ti-nitrides in the VOD samples. In addition, the pitting resistance of the AOD samples increased with increasing Ti content and decreasing Ca content in the (Ti, Ca)-oxides. 相似文献
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This paper presents the measurement of decarburization of steel rods with an electromagnetic sensor using an analytical model both in online and offline scenarios. Loss of carbon (decarburization) at the steel surface can have a significantly detrimental effect on mechanical properties of products, since hardness, fatigue, strength and wear properties are strongly dependent on carbon content. Currently, measurement of decarburization is by destructive methods, such as metallographic observation or hardness tests on a sample cross-section after processing. A non-destructive EM method is proposed in this paper. An analytical solution for the inductance of a circular air-cored coil encircling a steel rod is deduced and further a simplified model is obtained which shows that for both online and offline cases, the thickness of the decarburisation layer is proportional to the inductance difference with and without decarburisation. Using this simplified model, decarburisation thickness can be obtained. The results have been verified by both finite element models and metallographic observations. 相似文献