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利用真空反应釜冶炼Cr12N高氮钢,在冶炼过程中通过改变冶炼温度、压力、底吹时间、底吹气量等条件,研究Cr12N高氮钢中氮含量。试验结果表明:当温度从1 560℃上升到1 620℃时,Cr12N高氮钢中N含量从0.37%迅速下降至0.34%;压力从1.1 MPa升至1.6 MPa时,钢水中的N含量从0.31%增加到0.39%,涨幅达25.8%。由于压力较高,钢液中的N含量与氮分压之间呈非线性关系,与Sievert定律存在一定的偏离;底吹时间在5~15 min范围内时,Cr12N高氮钢中N含量随着底吹时间的增加而增加,当底吹时间大于15 min时,Cr12N高氮钢中N含量趋于饱和;底吹流量在0.16~0.18 m3/h范围内,随着底吹流量的增加,Cr12N高氮钢中N含量呈显著上升的趋势,当底吹量达到0.18 m3/h时钢中N含量达到最大值,此后随底吹量的增大,钢中N含量开始降低。 相似文献
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钢包底吹氩位置对钢水去夹杂影响的水模型研究 总被引:1,自引:0,他引:1
基于相似理论,利用1:9水模型研究了钢包吹氩钢水中夹杂物的物理行为,试验了不同底吹位置下吹气时间2~28 min、吹气量(1.19~4.75)×10-2m3/h对夹杂物去除行为的影响。结果表明,较小吹气量在8 min内可将绝大部分的模拟夹杂物去除,而较大吹气量时,中心和偏心喷吹方式分别需要20 min和16 min;不管中心还是偏心喷吹方式,去夹杂效果均随吹气量的增加先增大后减小,且存在一个最佳去夹杂吹气量;较小吹气量范围内,偏心喷吹方式的去夹杂效果要优于中心喷吹方式,而较大吹气量范围内则相反。 相似文献
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应用欧拉-欧拉模型建立了钢包内钢液流动及混合过程的数学模型,考察了吹气量对中心底吹及偏心底吹钢包内流场及均混时间的影响。计算结果表明,钢包底部四周为流动缓慢区域;吹气量越大,一方面可以降低均混时间,另一方面会导致钢包自由液面的钢液流速增大,从而容易造成卷渣;从缩短混合时间,提高生产效率考虑,偏心底吹更为有利。 相似文献
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为研究钢包的双孔底吹气量对钢包混匀时间、波高及卷渣和渣眼形成的影响,优化底吹工艺,以国内某厂 150 t 钢包为原型建立了钢包物理模型,模拟现场底吹工艺,综合混匀时间、波高及卷渣和渣眼的变化规律分析得到较优底吹气量。 结果表明,底吹气量越大,混匀时间越短,当底吹气量从 0.6 m3/h 增加至 1.2 m3/h 时,混匀时间大幅度缩短,瞬时波高及波动较小,之后随底吹气量的增大,混匀时间减少,速率变缓慢,而波高大幅度增长;临界渣眼的底吹气量和临界卷渣底吹气量不同,随着底吹气量增大,渣眼面积和卷渣深度均变大。 综合分析表明,实际底吹气量选择1.2 m3/h 较为合适,在波高、渣眼面积、卷渣增加不明显的情况下,大幅度缩短了混匀时间。 相似文献
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本文介绍电弧炉从炉门、炉底吹氮,钢包中以氮代氩精炼钢液的情况;对采用电磁搅拌法、倒包法和吹气法取得的冶金效果进行比较;讨论了钢液净增氮量与钢种、精炼方法不同而异及其影响因素。 相似文献
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通过210t顶底复吹转炉-LF-RH-宽厚板坯连铸流程对Q345E、Q345GJC和BQ550D等钢种进行45炉次RH脱气工艺试验,研究了RH真空处理对钢水脱氢、脱氧和脱氮效果的影响。得出,在RH真空度≤270Pa,环吹氩流量1200~1500L/min,高真空时间≥10min,钢中氢含量可达到≤2×10-6;当高真空时间为16min时,钢中氢、氧、氮含量平均分别为2.0×10-6、13.2×10-6和41×10-6。 相似文献
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以某厂300tRH真空精炼装置为研究原型,建立1∶6.5的水力模型对RH喷吹精炼工艺进行物理模拟。研究了喷吹位置、喷吹气量及驱动气体流量对循环流量和均混时间的影响。结果表明:不同喷吹气量、驱动气体流量条件下,获得大循环流量和短均混时间的最优喷吹位置不同。较小的喷吹气量(2.98~3.53m3/h)或者较小的驱动气体流量(0.93~1.02m3/h)时,宜采用低顶枪枪位(153.8mm)喷吹;喷吹气量大于3.91m3/h或者驱动气体流量大于1.12m3/h时,宜采用真空槽底部喷吹角度120°的侧喷嘴喷吹。顶枪与侧喷嘴复合喷吹有利于提高RH喷吹工艺的适应性及循环效率。 相似文献
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Based on the principles of thermodynamics and reaction kinetics, a dynamic model for the vacuum circulation (RH) process was developed. It comprises decarburisation, oxygen removal, dehydrogenation, denitrogenation and the course of steel temperature. The process model was validated by comparison of simulation results with measured process data from the RH/1 plant of Voest Alpine Stahl Linz (VASL). At this plant, it is used for on‐line observation of the contents of carbon, oxygen, hydrogen and nitrogen as well as the steel temperature. Based on cyclically measured values of vessel pressure, lift gas flow rate as well as waste gas flow rate and composition, the current heat status is calculated reliably. The accuracy of the carbon balance with measured waste gas values was improved remarkably by a model‐based correction calculation. The on‐line process observation system provides the operator with valuable information on the progress of vacuum treatment. 相似文献
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According to the analysis related to kinetic mechanism of vacuum denitrogenation and combining with the actual production of RH-MFB (a combination of Ruhstahl-Hausen vacuum degassing process with a multifunctional oxygen lance) at Liansteel, the limit step and model equation of vacuum denitrogenation are determined. Meanwhile, the influencing factors of nitrogen removal from liquid steel in vacuum of RH-MFB are analyzed. The results show that the limit step of vacuum denitrogenation in RH-MFB is the mass transfer of nitrogen in liquid boundary layer and the reaction follows first order kinetics. Keeping the necessary circulation time under the working pressure (67 Pa) is helpful to nitrogen removal from steel. The oxygen content in molten steel has little influence on the removal of nitrogen after deep deoxidation, while the sulphur content in liquid steel is always relatively low and has little effect on denitrogenation. The sharp decrease of carbon content in steel drives the process of denitrogenation reaction so as to exhibit a faster denitrogenation rate. The interfacial chemical reaction and argon blowing play a major role in the nitrogen removal when the carbon content in liquid steel is stable. 相似文献
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The characteristics and classification of decarburization and denitrogenation in the vacuum vessel for stainless steel production
are analyzed. Based on the analysis of movements of the liquid steel and bubbles, the kinetics of decarburization and denitrogenation
in the vacuum oxygen decarburization (VOD) process has been studied. A kinetic model of decarburization and denitrogenation
has been developed to simulate the VOD process, considering each reaction zone as oxygen blowing crater, bottom blowing plume,
steel/slag interface, and plume eye. As a result, it is possible to quantify the contribution of each reaction zone in decarburization
and denitrogenation rate at a different stage in the VOD process. Specific trials at a vacuum induction furnace were performed
to refine stainless steel in vacuum carbon deoxidation (VCD) and VOD style, respectively. The trial results are in good agreement
with the model calculation. Combining the trials and the model calculation and the influence of temperature control, critical
carbon content selection on the terminal total [C] + [N] content can be discussed further to provide a reasonable proposal
for high-quality ferritic stainless steel production.
This article is based on a presentation given at the International Symposium on Liquid Metal Processing and Casting (LMPC
2007), which occurred in September 2007 in Nancy, France. 相似文献
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The three–dimensional flow field of molten steel in an 80–ton single snorkel vacuum refining furnace has been mathematically simulated to attain the optimal configuration and operation parameters, such as the bottom blowing Ar flow rate, the eccentric position of bottom blowing Ar port at ladle bottom, the single snorkel inner diameter, and the single snorkel immersion depth into molten steel. The mathematical simulation results show that a stable flow field of molten steel can be achieved in 70–second; meanwhile, the maximal circulation intensity of molten steel in the 80–ton single snorkel vacuum refining furnace can be found on a cross–section with y as 0 mm based on the middle of ladle bottom as circular point of the Cartesian space coordinate under the condition of injecting Ar gas on x coordinate considering the asymmetry of flow field for molten steel in the single snorkel vacuum refining furnace. The recommended parameters of the 80–ton single snorkel vacuum refining furnace with ideal circulation intensity as 970.1 kg/s are the bottom blowing Ar flow rate as 450–500 Nl/min, the eccentric position of bottom blowing Ar port as 250 mm, the single snorkel inner diameter as 1000 mm, and the single snorkel immersion depth as 500 mm. 相似文献
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为了提高RH精炼效率,缩短精炼时间。以某钢厂150 t RH真空精炼装置为原型,建立相似比为1∶4的水模型,研究底吹孔个数与底吹流量的影响。结果表明,实施底吹工艺后,RH循环流量和混匀时间相较无底吹时都有明显改善。相同底吹流量情况下,单孔底吹对循环流量提升效果明显优于双孔底吹工况,如当底吹流量为90 L/min时,单孔底吹工况相较于无底吹工况循环流量增加34%,而双孔底吹工况只增加13%。底吹流量小于90 L/min时,单孔底吹和双孔底吹工况下混匀时间相差不大。底吹流量大于90 L/min时,双孔底吹工况下混匀时间反而有所增加。建议生产现场采用单孔底吹工艺,如采用双孔底吹工艺时,底吹流量应小于90 L/min。 相似文献