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Influence of Screw Design on Burden Descending Velocity and Particle Segregation in co.EX Shaft Furnace

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Journal of iron and steel Research International 2016年第6期23卷 516-524页

作者： Hai-feng LI Heng ZHOU Tao ZHANG Yang YOU Zong-shu ZOU Wan-ren XU School of Metallurgy Northeastern University Baoshan iron and steel co. Ltd.

co.EX shaft furnace（SF）is an industrial system that employs screw feeders;thus,the burden descending velocity and particle segregation in the SF can be directly affected by the design of screw.A three-dimensional actual size model of co.EX-3000 SF was established using the discrete element *** types of burdens,including pellet,ore,flux and co.e,were co.sidered in this *** this co.sideration,the effect of screw design on solid flow was *** showed that,in the base case,burdens fell primarily down from the first flight of the *** burden descending velocities were nearly uniform in the peripheral direction and decreased along the radial *** addition,the normalized particle size increased in the center area and decreased in the wall *** the flight diameter of screw benefited an even flow pattern and restrained the rolling tendency of burden from the edge to center *** optimized case was also proposed,in which a uniform solid flow profile co.ld be obtained and the evenness of descending velocity along the radius co.ld be greatly improved.

关键词： screw co.EX descending burden normalized radius Velocity segregation torque pellet

Technology Development for co.trolling Slab Transverse co.ner Crack of Typical Micro-alloyed steels

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Journal of iron and steel Research International 2015年第2期22卷 99-105页

作者： Hui ZHANG Chun-zheng YANG Ming-lin WANG Hong-biao TAO He-ping LIU Xue-bing WANG Central iron and steel Research Institute Shougang Jingtang United iron and steel co. Ltd.

A mathematical model for simulating the fluid flow, heat transfer and solidification in the co.ventional mold and the chamfer mold, together with a finite element stress-strain model in the straightening process of both molds, were established for the typical niobium, vanadium, and titanium micro-alloyed steels. On the basis of both numerical analysis, the mold co.per plate with an optimum chamfered shape was designed and applied in industrial tests. The predicted results from numerical simulation of fluid flow, heat transfer and solidification in the co.ven tional mold and the chamfer mold show that the increased chamfered angle leads to an approximately linear increase o[ the slab surface temperature, but it also causes strong flow near the slab co.ner. Very small chamfered length can lead to a significant increase of the temperature near the slab co.ner. However, with further increasing the chamfered length, the temperature of the slab co.ner increased slightly. The calculated results from the finite element analysis of stress-strain during the straightening process show that at the same slope width, the tangential strain on the slat） edges and co.ners is minimum when the chamfered angle is 30° and 45°, which is only 40° to 46° of rectangular slabs with the same cross-section area. At the same chamfered angle of 30°, when the chamfered length is co.trolled between 65-85 mm, the tangential strain on the part of the slab edges and co.ners is relatively smaller. Industrial test results show that the slab co.ner temperature at straightening segment increases about 100 ℃ by using chamfer mold co.pared to the co.ventional molds. The slab transverse co.ner cracks have been reduced more than 95° in co.parison with those in the co.ventional mold.

关键词： micro-alloyed steel transverse co.ner crack chamfer mold slab

Heat Transfer During Quenching by Plate Roller Quenching Machine

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Journal of iron and steel Research International 2013年第5期20卷 1-5页

作者： WANG Chao WANG Zhao-dong YUAN Guo WANG Dao-yuan WU Jun-ping WANG Guo-dong State Key Laboratory of Rolling and Automation Northeastern University nanjing iron and steel co. Ltd.

For plate quenching on a roller quenching machine, heat transfer process is investigated. Acco.ding to the practical online experiment of plate center temperature, average heat transfer co.fficient under different co.ditions and temperature fields are analyzed by numerical simulation. The results show that, at the water temperature of 15 ℃, the instantaneous maximum quenching co.ling rate is 17.6 ℃/s for the plate of 50 mm in thickness in roller quenching process. In the temperature range of 400-850 ℃, the maximum is 12.1 ℃/s. With the plate surface temperature decreasing, surface heat transfer co.fficient increases at first, and reaches the maximum value of about 15 000 W/（m^2·K）, and then decreases. The calculated heat transfer co.fficients are applied to analyze plate temperature field of different thicknesses, and the difference between the calculated and measured temperature is less than 5%.

关键词： plate roller quenching machine heat transfer co.fficient water temperature co.ling rate

Fabricating functionally graded Fe-Cr-co.permanent magnetic alloys via laser powder bed fusion

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Journal of iron and steel Research International 2024年第3期31卷 729-737页

作者： Ya-zhou He Ya-qing Hou Peng Shen Hao Zhang Dong Zhou Hang Su Central iron and steel Research Institute co. Ltd.Beijing 100081China Material Digital R&D Center China Iron and Steel Research Institute Group Co.Ltd.Beijing 100081China

Laser powder bed fusion(LPBF)in-situ alloying technology offers the possibility to co.struct gradient materials with varied structures and *** graded Fe-Cr-co.permanent magnetic alloys were fabricated by LPBF and in-situ alloying mixed powders of Fe,Cr,and co.*** effects of different Fe,Cr and co.co.tents on the microstructure,magnetic properties and hardness of Fe-Cr-co.alloys prepared by LPBF were *** as-built Fe-Cr-co.alloys present a single body-centered-cubic phase and have a homogeneous distribution of *** mechanical properties and magnetic properties of the co.positionally graded sample show a gradient *** the increase in Cr co.tent,the Vickers hardness of the sample increases,and the saturation magnetization of the sample *** optimal magnetic properties in an isotropic state are given as co.rcivity HcB=21.65 kA/m,remanence Br=0.70 T and energy product(BH)_(max)=5.35 kJ/m^(3),which are co.parable to or higher than the reported magnetic properties in an isotropic state prepared by traditional powder *** in-situ alloying technology has the potential to further explore Fe-Cr-co.magnetic materials,such as those co.sisting of multiple or more co.stituent elements,and to maximize the co.positional flexibility of magnetic materials.

关键词： Fe-Cr-co.alloy Laser powder bed fusion In-situ alloying Functional material Magnetic property

A Novel Low-co.t Hot Rolled High Strength steel for an Automatic Teller Machine

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Journal of iron and steel Research International 2015年第3期22卷 272-278页

作者： Bin ZENG Zhao-dong LI Xin-jun SUN Qi-long YONG Yu-qing WENG Technical Center Lianyuan Iron and Steel Co.Ltd. Department of Structural steels Central Iron and Steel Research Institute

A novel hot rolled steel LG600A with the tensile strength exceeding 700 MPa was developed for automatic teller machine application. Thelow-co.t C-Mn steel was microalloyed with：0.08 mass%- 0.12 mass% Ti rather than noble alloying elements, such as Nb, V, Mo, and Cu, etc. The novel steel had a good surface quality and welding property. After the hot rolled steel co.ls were leveled, the steel plates, the length of which was even down to 1 500 mm, had an excellent flatness. The effects of hot rolling parameters on mechanical per formance, m icrostructure and recrystallization behavior were studied. The metallurgical co.cept for the steel production was also discussed. The result shows that decreasing the finish rolling temperature, increasing co.ling rate in the first co.ling stage and decreasing the co.ling rate in the last co.ling stage, together with co.ling at a modestly high co.ling temperature all resulted in the refined grains and TiC precipitates, thereby improving the strength and toughness of this new steel greatly.

关键词： automatic teller machine high strength steel microstructure rolling parameter

Effect of Pre-deformation on Grain Ultrafining by Intercritical Deformation in Low-Carbon Microalloyed steels

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Acta Metallurgica Sinica(English Letters) 2018年第10期31卷 1038-1048页

作者： Ba Li Qing-You Liu Shu-Jun Jia Yi Ren Bing Wang Central iron and steel Research Institute Beijing 100081China iron and steel Research Institute Ansteel Group Co. Ltd.Anshan 114009 China

In this study, the effect of pre-deformation at recrystallization and non-recrystallization zone on the grain ultrafining by the subsequent intercritical deformation （ID） was investigated on low-carbon microalloyed steel. The results showed that ultrafine grain microstructure with an average size of - 1.0 μm was fabricated through pre-deformation in the recrys- tallization zone followed by ID. When pre-deformed at the non-recrystallization zone prior to ID, the grain size increased to 1.6 μm with a heterogeneous distribution along with the well-developed dynamic reco.ery of ferrite. The grain ultrafining mechanism was attributed to the co.bined action of the deformation-induced ferrite transformation and the co.tinuous dynamic recrystallization. In particular, the co.tinuous dynamic recrystallization process during ID occurred on the pro-eutectoid ferrite as a result of the subgrain rotation mechanism and the absorbing dislocations mechanism.

关键词： Low-carbon microalloyed steels Intercritical deformation Ultrafine grain co.tinuous dynamic recrystallization Deformation-induced ferrite transformation

Effect of Heat Treatment on Microstructures and Mechanical Properties of Hot-Dip Galvanized DP steels

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Acta Metallurgica Sinica(English Letters) 2014年第3期27卷 469-475页

作者： Enbao Pan Hongshuang Di Guangwei Jiang Chengren Bao State Key Laboratory of Rolling and Automation Northeastern University Benxi iron and steel co. Ltd Shougang Jingtang United iron & steel co. Ltd

In order to simulate the hot-dipped galvanizing of dual-phase （DP） steel （wt%） 0.15C-0.1Si-1.7Mn, the DP steels were obtained by different annealing schedules. The effects of soaking temperature, time, and co.ling rate on ferrite grain, volume fraction of martensite, and the fine structure of martensite were studied. Results showed that the yield strength （YS） of DP steel is sensitive to annealing schedule, while total elongation has no noticeable dependence on annealing schedule. Increasing soaking temperature from 790 to 850 ℃, the YS is the lowest at soaking temperature of 850 ℃. Changing CR1 from 6 to 24 ℃/s, the YS is the highest when CR1 is 12 ℃/s. Increasing soaking time from 30 to 100 s, the YS is the lowest at soaking time of 100 s. Besides, it was found that sufficient movable dislocations within ferrite grains and high martensite volume fraction can eliminate yield point elongation, decrease the YS, and increase ultimate tensile strength. Through TEM observations, it was also found that increasing annealing temperature promotes austenite transformation into twin martensite, and increases volume fraction of martensite at sufficient co.ling rate. With increasing the martensite volume fraction, the deformation substructure in the ferrite is well developed.

关键词： Advanced high strength steels (AHSS) Dual-phase (DP) steel Microstructure Annealing temperature

Experimental study on 830 MPa grade pipeline steel co.taining chromium

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International Journal of Minerals,Metallurgy and Materials 2009年第3期16卷 273-277页

作者： Yi Ren Shuai Zhang Shuang Wang Wen-yue Liu Technical Center Anshan Iron ＆ Steel Co. Ltd. Ar shan 114009 China

The diversity of microstructure and properties of 830 MPa grade pipeline steel co.taining chromium was investigated by optical microsco.e and transmission electron microsco.y. The main microstructures were multiple co.figurations, co.taining lath bainite and granule bainitc. Mechanical properties test results showed that the yield strength and tensile strength improved with increasing chromium co.tent. The toughness and elongation decreased at the same time, so temper process was introduced. Appling proper temper parameters, the values of toughness and elongation were improved dramatically, and the strength decreased slightly.

关键词： chromium high strength pipeline steel thermo-mechanical co.trolled process

Preparation of CaO-Al_2O_3-SiO_2 system glass from molten blast furnace slag

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International Journal of Minerals,Metallurgy and Materials 2014年第2期21卷 169-174页

作者： Ying Xu Yong-zang Zhang Lin-yan Hou Xiang Lu co.lege of Material Science and Engineering Hebei United University Xingtai iron and steel co. ltd.

To use the potential heat of molten blast furnace slag co.pletely, a CaO-Al2O3-SiO2 system glass （MSG） was prepared from the molten industrial slag. The co.responding method proposed in this study utilized both slag and its potential heat, improving the production rate and avoiding the environmental pollution. Using appropriate techniques, an MSG with uniform co.or and superior performances was produced. Based on the experimental results and phase diagram, the chemical co.position of MSG by mass is obtained as follows：CaO 27%-33%, SiO2 42%-51%, Al2O3 11%-14%, MgO 6%-8%, and Na2O＋K2O 1%-4%. Thermodynamic processes of MSG preparation were analyzed, and the phases and microstructures of MSG were investigated by X-ray diffraction （XRD） and scanning electron microsco.y （SEM）. The results show that alkali metal oxides serve as the fluxes, calcium oxide serves as the stabilizer, and alumina reinforces the Si-O network. XRD and SEM analyses show that, the prepared MSG displays the glass-feature patterns, the melting process is more co.plete, and the melt visco.ity is lowered with an increase in calcium oxide co.tent;however, a co.tinuous increase in slag co.tent induces the crystalli-zation of glass, leading to the formation of glass subphase. The optimum co.tent of molten slag in MSG is 67.37wt%. With respect to bend-ing strength and acid/alkali resistance, the performance of MSG is better than that of ordinary marble.

关键词： industrial wastes slag glass thermodynamics microstructure waste utilization heat reco.ery