钢铁钒钛

Study on Molten Salt System in Chlorination Furnace for TiCl₄ Production

Lu Hui, Yang Renmu, Meng Jun, An Jianguo, Xie Hongyan, Xie Gang

2013, 34(5): 1-8. doi: 10.7513/j.issn.1004-7638.2013.05.001

Abstract(108) PDF(5)

Abstract:
The chemical compositions,phase structures and microstructures of cold molten salt are studied. It is found that the molten salt system exists in complexus of TiO₂,SiO₂,chloride molten salt,calcium oxides and iron oxides. Molten salt system agglomerates under cold condition with uneven appearance and loose state. The longitudinal and transverse distributions of important components in the molten salt are researched by systematic sampling. The results show that at longitudinal section,the contents of TiO₂,SiO₂ and Al₂O₃ increase gradually from top to bottom,and the contents of C,FeCl₂ and FeCl₃ decrease gradually from top to bottom while most of the components at transverse section do not show a apparent rule.

Experimental Study on Titanium Soluble Anode Prepared with Different Carbonaceous Reducing Agent

Zhu Fuxing, Deng Bin, Mu Tianzhu

2013, 34(5): 9-14. doi: 10.7513/j.issn.1004-7638.2013.05.002

Abstract(55) PDF(1)

Abstract:
Theoretical thermodynamic data of TiC_0.5O_0.5 production by carbon thermal reduction were calculated by thermodynamic software combined with the latest technology research progresses. The processes of TiO₂ reduction with graphite,carbon black,and petroleum coke were tested by DSC-TG,and titanium soluble anodes prepared with different carbonaceous reducing agent were analyzed by XRD and SEM. The results show that Gibbs free energy and temperature of the solid solution TiC_0.5O_0.5 meet the relation of ΔG=385 418-262.1 T,and high temperature and low vacuum are beneficial for preparing solid solution TiC_0.5O_0.5. The processes of TiO₂ reduction with graphite and carbon black are similar,but different from that with petroleum coke. The initial temperature of solid solution TiC_0.5O_0.5 preparation with graphite is lower than those of the other two carbonaceous reducing agents. TiC_0.5O_0.5 can be acquired by graphite and carbon black reduction,but the reaction of petroleum coke is incomplete,and solution particles prepared with graphite are homogeneous.

Vanadium Extraction by Acid Leaching after Calcification of Molten Vanadium Slag

Li Kun, Song Wenchen, Zheng Quan, Li Hong

2013, 34(5): 15-18,22. doi: 10.7513/j.issn.1004-7638.2013.05.003

Abstract(98) PDF(2)

Abstract:
The process of extracting vanadium from molten vanadium slag was simulated. After vanadium slag was heated to the molten state,CaO was charged and oxygen was blown into the slag,by which vanadium in the slag was oxidized into quadrivalent or pentavalent state and calcium vanadate was obtained.Then acid leaching was employed to extract vanadium. The influence of calcium to vanadium ratio,sulfuric acid concentration and solid-liquid ratio on leaching ratio was investigated. The experiment results show that the calcium vanadate is mainly CaV₂O₅,and with 70% of the slag's particle size smaller than 0.074mm,calcium to vanadium ratio of 0.5~0.9,leaching temperature of 90℃,reaction time of 120min,solid to liquid ratio of 1:5,and sulphuric acid concentration of 20%,vanadium leaching ratio can reach 88% or above.

Study on Preparation of TiO₂ from Aqueous TiCl₄ Solution by Pyrohydrolysis

Zhang Peng, Liu Daijun, Mao Xuehua

2013, 34(5): 19-22. doi: 10.7513/j.issn.1004-7638.2013.05.004

Abstract(86) PDF(5)

Abstract:
Taking TiOCl₂ solution prepared by hydration of TiCl₄ as raw material,crystalline TiO₂powder was prepared by pyrohydrolysis of self-generating seed crystal under a pressure of 1 atm. With Ti⁴⁺ concentration in the initial TiOCl₂ solution of 0.5 mol/L,after reaction at 106℃ for 120 min,the product obtained was proved to be a mixture of rutile,anatase and brookite powder by X-ray diffraction analysis. And pure rutile TiO₂ powder could be prepared after calcination. The influence of the concentration of Ti⁴⁺ and reaction temperature and time on size distribution of the products was investigated. It can be concluded that with Ti⁴⁺ concentration of 0.5 mol/L and reaction time of 120 min,TiO₂ power with minimum particle size can be obtained,and as the hydrolysis temperature reduces,the TiO₂ particle size becomes smaller.

Study on Preparation of W,N Codoped TiO₂ Photocatalyst by Low-temperature Sol Process

Meng Bo, Wang Xiaojing, Li Xue, Liu Yunyi

2013, 34(5): 23-27,32. doi: 10.7513/j.issn.1004-7638.2013.05.005

Abstract(57) PDF(1)

Abstract:
Taking tetra-n-butyl titanate as precursor and ammonium nitrate and ammonium tungstate as codoping sources,nanoscale W,N codoped TiO₂ powder is directly prepared by low-temperature sol process. The samples are characterized by XRD,SEM,IR,XPS,and GTA. The results show that the spherical codoped photocatalyst powder is anatase TiO₂ with particle sizes of 8.9 nm and good stability below 600℃; the energy gap of the powder is 2.86 eV and the photoresponse moves to the range of visible light. Sunlight is replaced by xenon lamp to degrade methyl orange solution for 60 min,and the degradation rate of the photocatalyst powder reach to 94% or above,which shows a noticeably improved performance than that of P25.

Experiment on Direct Reduction of Iron from Vanadium Extraction Tailings by Adding Carbon

Yang He, Mao Linqiang, Xue Xiangxin, Liu Dong

2013, 34(5): 28-32. doi: 10.7513/j.issn.1004-7638.2013.05.006

Abstract(63) PDF(1)

Abstract:
The process of direct reduction of iron from vanadium extraction tailings by directly adding carbon was investigated. The effect of C/O ratio and reduction temperature and time on direct reduction of iron was analyzed by X-ray diffraction and scanning electron microscopy etc. The result shows that with the reduction temperature and time of 1200℃ and 30 min respectively,and C/O ratio of 2.5,the metallization ratio of iron can reach about 85%; the metallization ratio increases with the increase of temperature and reduction time; during the reduction,the element Fe varies following Fe₂O₃→Fe₃O₄→FeO→Fe; the quality of the iron is affected with the extension of reduction time.

Research on Comprehensive Recycling of Blast Furnace Dusts

Jia Jihua, Han Hongliang, Duan Dongping, Geng Yejing, Liu Jing

2013, 34(5): 33-37. doi: 10.7513/j.issn.1004-7638.2013.05.007

Abstract(173) PDF(5)

Abstract:
In this article,based on analysis on properties of blast furnace dusts in Tangshan,a process for comprehensive recycling of blast furnace dusts is put forward and validated through a range of tests.The results show that in the process,blast furnace dusts including Fe and C can be effectively recycled,and non-ferrous metals such as K,Na,Pb,and Zn can also be separated and collected through multistage hydrometallurgical process,which realizes the comprehensive utilization of blast furnace dusts. The researches prove that it is the best way to utilize blast furnace dusts.

Research on Cleanliness of IF Steel During Casting Process

Tang Dechi, Gao Shengyong, Cui Yang, Tian Zhihong, Zeng Zhi, Zhang Hongyan, Pang Zaigang

2013, 34(5): 38-42. doi: 10.7513/j.issn.1004-7638.2013.05.008

Abstract(75) PDF(2)

Abstract:
Cleanliness of IF steel during casting process was systematically investigated. The research on T[O]in RH-tundish-slab shows that from tundish to slab,average contents of T[O]decrease from 31× 10^-6 to 20 × 10^-6while average contents of nitrogen increase from 16.5 × 10^-6 to 19.6 × 10^-6. The analysis on inclusions in tundish for the first three heats of a casting batch shows that the number of inclusions with diameters smaller than 2 μm reduces significantly to no more than 50 percent of the initial amount. Original position analysis(OPA) on surface inclusions in head slab,tail slab and normal slab shows that the content of Al series inclusions in head slab is apparently higher than those in normal slab and tail slab; the distribution tendency of Al series inclusions in different depth in inner arc is consistent with that in outer arc; where the distance to the surface is 1.6 mm,the content of Al series inclusions the lowest; where the distance to the surface is above 1.6 mm,the content increases while the distance above 3.2 mm,the content tends to decrease.

Research on Combustion-supporting Mechanism of Fe₂O₃ for Blast Furnace Coal Injection

Liu Xiaojie, Feng Shuai, Lv Qing, Zhang Shuhui

2013, 34(5): 43-47. doi: 10.7513/j.issn.1004-7638.2013.05.009

Abstract(60) PDF(1)

Abstract:
Fe₂O₃ is a kind of pulverized coal combustion improver suitable for blast furnace. TG-DSC analysis is employed to study the combustion mechanism,and the result shows that FeCO-R weakens bridged bond of carbon structural units and changes crystal structures,resulting in lowered activation energy of the pulverized coal and accelerated combustion. Combustion conditions of the blast furnace are simulated,and then unburned coal are collected and analyzed by XRD and SEM. The results show that with the addition of the combustion improver Fe₂O₃,microcrystal parameters of the unburned coal increase,and height and diameter of aromatic lamella increase by 0.001 1 nm and 0.001 2 nm respectively; particles size of the unburned coal powder decreases by 3.48 μm with irregular morphological appearances.

Practice of Blast Furnace Protection with Titanium-containing Sinter

Sun Yaping, Liu Pengjun, Lv Jiali, Wang Jun

2013, 34(5): 48-51. doi: 10.7513/j.issn.1004-7638.2013.05.010

Abstract(69) PDF(2)

Abstract:
In view of erosion of furnace hearth and bottom and increase of water temperature difference of cooling wall,titanium-containing sinter instead of titanium ore is used for furnace protection. Through calculation of titanium balance in the blast furnace,titanium content in hot metal in the furnace is controlled,and reasonable operation system and smelting parameters are selected. The production practice shows that the temperature at the side wall of the furnace hearth and water temperature difference of cooling wall decrease,which realizes the effect of furnace protection as well as effective and lowcost production.

Production Practice on Control of Purity for Cord Steel in Pangang

Zhang Qiang, Li Yangzhou, Chen Liang, Huang Yuming, Xu Huabin

2013, 34(5): 52-57. doi: 10.7513/j.issn.1004-7638.2013.05.011

Abstract(43) PDF(1)

Abstract:
Due to the extremely strict requirements on the control of [S],[N],[O] and [Ti] content in molten steel,tire cord steel is a kind of wire rods difficult to be produced. Pangang Vanadium Recovery and Steelmaking plant steelmake using hot metal with containing [V]and [Ti],the hot metal heat source is insufficient,and the elemente of [P]and [S]content is higher,so make the process of controlling cord steel production more difficult。Usually,using hot metal desulphurization control the content of [S] under 0.005%,though extending oxygen blowing time 3~5 min in the process of extract vanadium converter,can make the content of [Ti] below 0.003% in the semisteel,in the process of converter,controlling the end-point oxygen activity and the LF process refining using slag formation of reasonable slagging,RH vacuum treatment,can produce meetting the requirements of GB/T 10561-2005 steel cord.

Study on Heat Transfer Behavior on Broadside Copper Plate of Mold for Thin Slab Continuous Casting

Yuan Lintao, Zhang Hui, Shi Zhe, Tao Hongbiao, Zhang Yong

2013, 34(5): 58-62. doi: 10.7513/j.issn.1004-7638.2013.05.012

Abstract(32) PDF(1)

Abstract:
Temperature distributions on CSP mold copper plate of a certain steel mill are measured by a mold temperature monitoring software. A two-dimension model for mold heat flux distributions is built on the basis of casting parameters including real-time copper temperature,original temperature of cooling water,and temperature differences of cooling water. The effect of slab width and casting speed on the heat flux distribution on the meniscus is discussed. The results show that the distributions of heat flux and temperature in mold are nonuniform. The uniformity of the heat flux distribution is increased with the increase of slab width or the decrease of the casting speed.

Research on Thermal Properties of Cast Iron Cooling Stave of Taphole

Shi Lin, Wang Zhigang

2013, 34(5): 63-68. doi: 10.7513/j.issn.1004-7638.2013.05.013

Abstract(52) PDF(1)

Abstract:
In order to satisfy the requirement of blast furnace on longevous cooling stave,the temperature and stress field of the newly designed cast iron cooling stave of taphole are calculated by using the ABAQUS. The results show that the maximum temperature of hot surface is 85.22℃ which leads to small deformation at the early stage of taphole opening. When the lining erosion thickness increases from 50 mm to 1 100 mm,the temperature of the hot surface at the taphole corner increases from 87.16℃ to 234.9℃. In addition,the stress at the middle part of the stave increases from 130.3 MPa to 294.0 MPa which is close to the yield strength of the stave,but the stresses at locating pins greatly exceed the yield strength of the stave. The results indicate that the weak cooling area of the newly designed cooling stave is near the taphole corner and central line,and the stress concentrates near the locating pins. This study provides a theoretical basis for improving the design and installation of the cast iron cooling stave of taphole.

Research on Erosive Wear Resistance of Precipitation Hardening Stainless Steel 0Cr17Ni7Al

Zhu Tao, Wang Shuqi, Ji Xiulin

2013, 34(5): 69-74,88. doi: 10.7513/j.issn.1004-7638.2013.05.014

Abstract(71) PDF(3)

Abstract:
Erosive wear resistance of precipitation hardening steel 0Cr17Ni7Al was investigated via self-made solid-liquid two-phase-flow erosive wear tester,and the effect of heat treatment on the erosive wear resistance of the steel was studied. Furthermore,through comparison with H₁₃ steel which has the similar hardness with the steel,its erosive wear mechanism was also discussed. The experimental results show that the specimens undergone solid solution treatment at 1 040℃ and aged at 520℃ present the best erosive wear resistance. As erosive time increases,the weight loss ratio of steel 0Cr17Ni7Al increases first and then keeps at a stable value,showing a noticeable influence by work hardening rate and erosive angle. As the erosive angle increases from 15° to 90°,the weight loss due to erosive wear increases first and then decreases with the maximum value at 45°. Steel 0Cr17Ni7Al has better wear-resistant properties at small angles than H₁₃ steel while they have basically the same erosion maximum. Based on surface morphology observation,the erosive wear mechanism of slurry on materials in the research is mainly extrusion. Therefore,higher strength and hardness is beneficial for improving erosive wear resistance.

Experimental Study on Ultrahigh-strength Strapping Steel

Li Feng, Yang Honggang, Lü Jiashun, Zhang Leng, Gao Wei, Gao Hong

2013, 34(5): 75-78. doi: 10.7513/j.issn.1004-7638.2013.05.015

Abstract(25) PDF(1)

Abstract:
Ultrahigh-strength strapping steel is used for packing paper,tobacco and compressed cotton and wool. At present,there is only one company that can produce it through lead quenching. In this paper,the feasibility to produce a kind of ultrahigh-strength strapping steel with tensional strength of1 350 MPa and elongation of 12% by environmentally friendly continuous annealing process is investigated. The experiment results of steelmaking,hot rolling,pickling,cold rolling and continuous heat treatment show that the steel with the above-mentioned properties can be obtained by using the newly-designed chemical composition scheme. The microstructures and X-ray diffraction spectrum of the steel show that the steel is strengthened and toughened by martensite and residual austenitic. The effect of continuous heat treatment on microstructure and mechanical properties is also discussed.

Influence of Isothermal Temperature on Formation of Intragranular Ferrite in Vanadium-microalloyed Steels

Wang Andong, Tian Linmao, Zuo Zhenli, Wang Junyu

2013, 34(5): 79-82. doi: 10.7513/j.issn.1004-7638.2013.05.016

Abstract(38) PDF(1)

Abstract:
Microalloying of steels refers to adding a small amount of microalloying elements into steels,which can significantly enhance the mechanical properties of steels. In this paper,the research object is medium-carbon microalloyed steel containing vanadium. After aging treatment at 900℃,and isothermal treatment at 680,600,550 and 500℃ respectively,the influence of isothermal temperature on the formation of intragranular ferrite is studied,and the microstructures are observed. The results show that after heat preservation at 900℃,there is a significant increase of ferrite content in the original sample from 5.26% to 37.94%. After isothermal treatment,with the decrease of isothermal temperature,the crystallographic form of ferrite transforms from lumps to short rod-like shape. As the temperature further reduces,it transforms from short rod-like ferrite to acicular ferrite; with the decrease of temperature,ferrite content in the tested steel gradually increases while the grain size gradually decreases.

Effect of Annealing Temperature on Texture, Microstructure and Properties of Ti-IF Steel

Tang Xingchang, Li Jipeng, Zheng Yueqiang

2013, 34(5): 83-88. doi: 10.7513/j.issn.1004-7638.2013.05.017

Abstract(43) PDF(1)

Abstract:
Composition design and process control of Ti-IF steel by CSP process is introduced in this article,and through simulation of batch annealing in laboratory,the effect of annealing process on texture,microstructure and properties is researched. The textures and microstructures of Ti-IF steel treated with different annealing process are analyzed by optical microscope, electron back-scatter diffraction(EBSD) and X-ray diffractometer(XRD). The results indicate that with the increase of annealing temperature,{111} texture is enhanced,and r value increases,resulting in the improvement of uniformity of microstructures and deep drawability. It can be concluded that the increase of annealing temperature is favorable to obtain excellent comprehensive properties of Ti-IF steel.

Analysis on Formation of Delayed Cracks of Abrasion-resistant Steel Plate NM400 after Cutting

Zhang Tao, Hou Huaxing, Yang Jun, Sui Xiaohong, Liu Ming

2013, 34(5): 89-94. doi: 10.7513/j.issn.1004-7638.2013.05.018

Abstract(56) PDF(4)

Abstract:
The causes of delayed cracks forming in 80 mm-thick abrasion-resistant steel plates NM400 after cutting were investigated by analyzing macrostructures and microstructures of the plates,and countermeasures to avoid such kind of cracks were considered. The result shows that there are several center contraction cavities and segregations in the mid-depth of the plate,and microstructures there are coarse; the impact of various residual stresses generating during heat treatment and the flame cutting process on this area is the main reason for the formation of the delayed crack. The delayed cracks can be effectively avoided by reducing defects in continuously cast blooms and improving heat treatment and cutting process.

Effect of Diffusion Annealing Temperature on the Coating of Hot-dip Aluminized Carbon Steel

Liao Yuanlu, Wang Shuqi, Zhang Qiuyang, Wang Lan

2013, 34(5): 95-98,104. doi: 10.7513/j.issn.1004-7638.2013.05.019

Abstract(55) PDF(1)

Abstract:
Fe-Al intermetallic matrix composite coating was prepared on the surface of steel C45 by hotdip aluminizing,then the sample was processed at different diffusion annealing temperature. The structures and chemical compositions of the coating were analyzed by XRD and SEM etc. The effect of diffusion annealing temperature on alloy layer and the conversion mechanism of the layer was discussed. The results show that the main phases of the coating are Fe₂Al and Al₂O₃ when the temperature is at 700~800℃; as the temperature exceeds 800℃,the phase of the alloy layer varies from brittle phase(Fe₂Al₅) to tough phases(FeAl and Fe₃Al); the alloy layer is completely converted to FeAl and Fe₃Al when the diffusion temperature is at 1 000℃. Fe₂Al₅ is featured by great hardness but it tends to crack due to its brittleness. Although the hardness of FeAl and Fe₃Al is lower than that of Fe₂A₅,their toughness is so excellent that they can effectively hinder the formation and expansion of cracks in the coating,and they can integrate closer with the matrix.

Opportunities for Vanadium Microalloying in AHSS for the Automotive Sector

Scott C P, Milbourn D, Huang M, Perrard F

2013, 34(5): 99-104. doi: 10.7513/j.issn.1004-7638.2013.05.021

Abstract(83) PDF(3)

Abstract:
In this article we review some of the advances made in Vanadium microalloying technology for flat products published over the past 10 years and discuss their application to Advanced High Strength Steels(AHSS) for the automotive sector. The potential benefits to a range of steel grades including Dual Phase(DP),fully bainitic,TRansformation Induced Plasticity(TRIP) and TWinning Induced Plasticity(TWIP) are discussed and examples are given. Areas of ongoing research which merit support from AHSS producers are identified.

2013, 34(5): 105-106.

Abstract(28) PDF(1)

Abstract:

2013 Vol. 34, No. 5