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Study on temper-rapid cooling process of low carbon steel produced by CSP

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Journal of university of science and technology beijing 2007年第4期14卷 312-316页

作者： huajie wu yangchun liu jie fu metallurgical and ecological engineering school University of Science and Technology Beijing Beijing 100083 China

On the basis of the effect of carbon precipitation on the microstructure and properties of steel products below At temperature, a new thermal treatment method （temper-rapid cooling process） was studied. By the temper-rapid cooling process, the yield strengths of the high strength low carbon （HSLC） steel ZJ330 and SPA-H produced using the compact strip production （CSP） process increased from 340 to about 410 MPa and from 410 to about 450 MPa, respectively. The results indirectly indicated that there existed nanoscaled iron-carbon precipitates that have obvious precipitation effect on low carbon steel produced by CSP. The prospect of application is discussed.

关键词： temper-rapid cooling HSLC steel yield strength CSP

Nano-scaled iron-carbon precipitates in HSLC and HSLA steels

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science china(Technological sciences) 2007年第2期50卷 166-176页

作者： fu jie wu huajie liu yangchun KANG YongLin school of metallurgical and ecological engineering University of Science and Technology BeijingBeijing 100083China school of Materials science and engineering University of Science and Technology BeijingBeijing 100083China

This paper studies the composition, quantity and particle size distribution of nano-scaled precipitates with size less than 20 nm in high strength low carbon (HSLC) steel and their effects on mechanical properties of HSLC steel by means of mass balance calculation of nano-scaled precipitates measured by chemical phase analysis plus SAXS method, high-resolution TEM analysis and thermodynamics calculation, as well as temper rapid cooling treatment of ZJ330. It is found that there existed a large quantity of nano-scaled iron-carbon precipitates with size less than 18 nm in low carbon steel produced by CSP and they are mainly Fe-O-C and Fe-Ti-O-C precipitates formed below temperature A1. These precipitates have ob- vious precipitation strengthening effect on HSLC steel and this may be regarded as one of the main reasons why HSLC steel has higher strength. There also existed a lot of iron-carbon precipitates with size less than 36 nm in HSLA steels.

关键词： HSLC steel high strength low alloyed steel (HSLA steel) iron-carbon precipitates precipitation strengthening

Study on Temper-Rapid Cooling Process of Steel

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Study on Temper-Rapid Cooling Process of Steel

Particle size segregation in hopper at a bell-less top blast furnace with parallel hoppers

2006年薄板坯连铸连轧国际研讨会

作者： wu Hua-jie liu Yang-chun fu jie (school of metallurgical and ecological engineering university of science and technology beijing beijing 100083.

Based on the effect of carbon precipitation under the A1 temperature on the microstructure and properties, a new thermal treatment method(temper rapid cooling process) has been studied in this paper.

关键词： temper-rapid cooling HSLC steel yield strength

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Baosteel Technical Research 2010年第S1期4卷 14-页

作者： KOU Mingyin,wu Shengli,XU Jian,fu Changliang,liu Chengsong,GUO Xinying and DU Kaiping school of metallurgical and ecological engineering,university of science and technology beijing,beijing 100083.china

Owing to a certain angle existing between a belt conveyor and the parallel hoppers,and the hoppers localizing away from the centerlines of a blast furnace,particles size segregation is likely to happen in a bell-less top blast furnace with parallel *** the law of particles size segregation in hoppers could help to choose better charging parameters and optimize production and technical *** for the previous works on burden segregation at a bell-less top blast furnace with parallel hoppers,more attention was paid to the falling point segregation and the circumferential mass flow segregation while charging from the tilting chute,but ignoring the particle size segregation in burden hoppers as burden falls from a belt conveyor,which is the right basis of analyzing the former,and plays a significant role in controlling the gas distribution in the blast *** present work takes ternary mixtures of coke in three different particle sizes to simulate the size segregation of the coke charged into the hoppers by *** effect of the main striking point on size segregation is also *** research shows that there exists a good linear relation between segregation coefficient k and the dimensionless main striking point when using the equation C = C_0~k to express the degree of size segregation in *** linear relation is proposed for the first time and provides a new way to predict the size segregation in hoppers,which forms a theoretical basis and technical support for reducing the size segregation degree in hoppers.

关键词： blast furnace bell-less top with parallel hoppers particle size segregation in hoppers

Improvements on Calculation Model of Theoretical Combustion Temperature in a Blast furnace

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Journal of Iron and Steel Research International 2011年第12期18卷 1-5页

作者： wu Sheng-li liu Cheng-song fu Chang-liang XU Jian KOU Ming-yin school of metallurgical and ecological engineering University of Science and Technology Beijing Beijing 100083 China

On the basis of the existing originally modified calculation models of theoretical combustion temperature（TCT）,some factors,such as the combustion ratio of pulverized coal injection（PCI）,the decomposition heat of PCI and the heat consumption of SiO2 in ash reduced in high temperature environment,were amended and improved to put forward a more comprehensive model for calculating *** influences of each improvement on TCT were studied and the results were analyzed compared with those of traditional model and originally modified model,which showed that the present model could reflect the thermal state of a hearth more effectively.

关键词： blast furnace theoretical combustion temperature improved calculation model

Coke Collapse Model and Collapse Profile Variation Law for Bell-Less Top BF

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Journal of Iron and Steel Research International 2011年第10期18卷 8-12页

作者： wu Sheng-li fu Chang-liang liu Cheng-song XU Jian KOU Ming-yin school of metallurgical and ecological engineering University of Science and Technology Beijing Beijing 100083 China

The mathematical model of minimum safety factor that investigated the collapse trends of coke layer under different charging parameters was established firstly on the basis of the slope stabilization theory in soil mechanics, and then the model of burden profile after coke collapse was improved by adopting the predetermination of quadratic curve and energy correction methods. The research will provide theoretical evidences for describing the coke profile more accurately and technical direction for choosing suitable charging parameters of blast furnace. The results show that： it is helpful to improve the stability of coke layer with increasing chute inclining angle and length of the coke flat; when the main falling point of ore moves toward furnace wall or the coke flat is wider, the curve radian of burden profile after coke collapse becomes smaller; the ore to coke ratio distribution agrees with the gas top temperature measurement well under considering coke collapse comparing with the result of ignoring coke collapse.

关键词： blast furnace coke layer stability safety factor coke collapse burden profile

Effect of Nb and V on the continuous cooling transformation of undercooled austenite in Cr–Mo–V steel for brake discs

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International Journal of Minerals,Metallurgy and Materials 2018年第8期25卷 892-901页

作者： Dan wu fu-ming Wang Jin Cheng Chang-rong Li school of metallurgical and ecological engineering University of Science and Technology Beijing school of Materials science and engineering University of Science and Technology Beijing

The increasing speed of trains necessitates the development of brake-disc materials that meet more stringent ***,Nb and V have been added to Cr–Mo–V steel to improve its thermal fatigue performance when used in brake *** this paper,the influences of Nb and V on the static continuous cooling transformation(CCT)behaviors of undercooled austenite were *** microstructures,hardness,and dislocation densities at different cooling rates and with the addition of different alloying elements were also *** results show that the transformation products of ferrite,granular bainite,lower bainite,and martensite form under different cooling *** increasing Nb and V contents,the CCT curves are shifted to the left,ferrite and bainite transformations are promoted,and the critical cooling rate of total martensite formation is *** added V mainly forms V-rich M_8C_7 precipitates and reduces the dissolved C content;therefore,the A_(c1),A_(c3),and M_s-point temperatures ***,the stability of retained austenite is also reduced;its content therefore *** with V,the effect of added Nb is weaker because of its smaller ***,the addition of Nb improves the hardness at lower cooling rates because of the precipitation of fine Nb C particles and refining of the microstructure.

关键词： brake-disc steel niobium vanadium microstructure continuous cooling transformation

Discrete element method study of solid descending and residence properties in COREX shaft furnace with center gas supply device

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Journal of Iron and Steel Research International 2019年第7期26卷 669-678页

作者： Heng Zhou Qin-fu Hou Ming-yin Kou Shun Yao Sheng-li wu school of metallurgical and ecological engineering University of Science and Technology Beijing Beijing 100083 China Department of Chemical engineering Monash University Clayton VIC 3800 Australia

Solid descending and residence properties in COREX shaft furnace with a center gas supply device (CGSD) were studied using the discrete element method. Solid flow pattern, residence time distribution, and local solid residence time (SRT) were analyzed. Moreover, the effects of the rotation speed of screws, the radius, and height of CGSD were investigated. The results show that the solid flow is dominantly a plug flow in the shaft furnace with the CGSD. In the upper region of the shaft furnace for gas-solid reduction, uniform distribution of local SRT is observed, which is preferable to match the even gas distribution expected due to the CGSD and slots. For different rotation speeds of the screws, the distribution of solid flow patterns is similar. The averaged residence time, dispersed plug volume fraction, and dead volume fraction decrease with increasing the rotation speed of the screws. The radius of the CGSD affects the solid residence in the shaft furnace. Local SRT above the CGSD increases with the increase in the radius of CGSD, possibly leading to the formation of more agglomerates. Hence, the radius of CGSD should be chosen carefully. The height of CGSD has a minor effect on solid residence in the shaft furnace.

关键词： COREX shaft furnace Solid residence time Discrete element method Center gas supply device Solid descending

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预测典型变形高温合金均匀化动力学的新模型

Transactions of Nonferrous Metals Society of china 2024年第4期34卷 1178-1190页

作者：张献光杨文超周扬闫建昊肖东平税烺付建辉孙飞石鹏陈佳俊裴逸武张健北京科技大学绿色低碳钢铁冶金全国重点实验室北京100083 北京科技大学冶金与生态工程学院北京100083 成都先进金属材料产业技术研究院股份有限公司成都610300 攀钢集团研究院有限公司攀枝花617000 Department of Material Design Innovation engineering Nagoya UniversityFuro-choChikusa-kuNagoya 464-8603Japan

提出一种基于扩散距离概念的变形高温合金均匀化动力学新预测模型。通过定量电子探针(EPMA)分析,系统研究典型镍基变形高温合金(GH4141)的微观偏析和均匀化动力学。研究发现,基于残余偏析指数模型预测的均匀化动力学与实际测量结果之间... 详细信息

提出一种基于扩散距离概念的变形高温合金均匀化动力学新预测模型。通过定量电子探针(EPMA)分析,系统研究典型镍基变形高温合金(GH4141)的微观偏析和均匀化动力学。研究发现,基于残余偏析指数模型预测的均匀化动力学与实际测量结果之间存在一定差异。实验和理论分析均表明,考虑了过去通常被忽略的扩散方向因子的一维扩散距离模型可以合理地预测均化动力学。新模型在只需知道原始枝晶臂间距和扩散系数前提下即可完成预测计算,这为变形高温合金均匀化动力学预测提供了一种新的选择。

关键词：变形高温合金微观偏析均匀化动力学预测模型扩散距离