钢铁钒钛

Experiment on the Conditions of Fluidization for Titanium Concentrate

Tan Liang, Yuan Xizhi, Zhang Yunling

2010, 31(2): 1-5,14.

Abstract(18) PDF(1)

Abstract:
The minimum velocity for gas to keep fluidization and fluidization quality for titanium concentrate were explored at different conditions that are titanium concentrate grain, layer height for reactant, and porosities on the distribution plate.It is shown that the porosities and layer height has little effect to the minimum velocity for gas to keep fluidization, but the minimum fluidization velocity increases with the increase of titanium concentrate grain.Additionally, under the very conditions for this experiment, the fluidization quality is satisfactory.

Preparation of Tungsten-doped VO₂ Thin Film with Low Phase Transition Temperature by Hydrogen Reduction Method

Li Minjiao, Zhang Shulin, Ding Xiumin, Luo Yi, Xiong Miao

2010, 31(2): 6-9.

Abstract(23) PDF(1)

Abstract:
V₂O₅ film was first fabricated by dipping a glass slide into a V₂O₅ gel containing a small quantity of polytungstate sol.Then the V₂O₅ film was reduced in hydrogen atmosphere at 400℃ for 3 h and then a tungsten-doped VO₂ thin film was prepared.The resulted film shows the characteristic green of VO₂.the content of W and V is 3.212% and 64.97%, respectively.The results of the curve of resistance-temperature show that the phase transition temperature of the VO₂ thin film is 40.5℃, the thermal hysteresis loop width is ΔT=11℃, amount of resistance mutation(ΔS) is 4.06 orders of magnitude.

Experimental Investigation on Fluidity of Hot Metal Bearing Titanium

He Yuanyuan, Liu Qingcai, Yang Jian, Chen Qianxiang, Ao Wanzhong

2010, 31(2): 10-14.

Abstract(31) PDF(1)

Abstract:
In allusion to the features that hot metal bearing Ti is easy to become viscous, the impact of [Si], [Ti] content on viscosity, melting temperature, and flow properties of hot metal was studied in the lab..Relationship between the solubility of titanium in molten iron and the temperature changes was calculated and analyzed which combined with thermodynamic.The results show that molten iron become viscous which mainly affected by the dissolution and precipitation effects of titanium. [Si] has a weakening effect on the dissolution of titanium.Titanium has little effect on the viscosity of hot metal when Σ[Si+Ti] about 0.6% and [Ti] below 0.29%.The choice of appropriate blast furnace temperature is the crux of preventing that hot metal containing titanium became viscous, hot metal sticks pot, slag iron is difficult separation and so on.

Determination of the Particle Size Distribution of Metatitanic Acid by Photon Correlation Spectroscopy

Tian Congxue, Hu Hongfei, Du Jianqiao, Chen Xinhong, Ma Weiping, Luo Jianlin, Liu Daijun

2010, 31(2): 15-19.

Abstract(20) PDF(1)

Abstract:
In order to measure the particle size distribution(PSD) of metatitanic acid slurry, hydrolyzed from sulfate titanium dioxide process, the influencing factors of dispersion methods and measurement conditions on the PSD of metatitanic acid were investigated by photon correlation spectroscopy(PCS).Dispersion medium, dispersant and its dosage, metatitanic acid dosage, ultrasonic dispersion time and stabilization time were studied to determine the optimum dispersion condition.The results showed that the optimum dispersion condition for the measurement of the particle size distribution of hydrated metatitanic acid by PCS is using distilled water as dispersion medium, 50 mL sodium hexametaphosphate of 0.05% as dispersant, hydrolyzed metatitanic acid about 0.044 g, and then measuring the PSD immediately after ultrasonic dispersion time 5 min.

Experimental Study on the Ti Microalloyed Q345E Steel

Wang Jianfeng, Deng Shen, Rao Jiangping, Li Guangqiang, Zhang Feng

2010, 31(2): 20-25.

Abstract(17) PDF(2)

Abstract:
The high performance Q345E steel with high yield strength and stable low-temperature impact toughness was made by Titanium microalloying technology.The microstructure of developed Q345E steel is composed of ferrite, pearlite and a little tempered sorbite.Slow cooling and fast cooling experimental results showed that titanium microalloyed Q345E steel has high performance stability, the increase of strength is caused mainly by grain-refining strengthening and precipitation strengthening.This research is a beneficial attempt for further promotion of titanium microalloyed steel.

Effect of Hot Rolling Parameters on the Microstructure and Properties of Ti Microalloyed Steel Produced by Compact Strip Production

Huo Xiangdong, Mao Xinping, Yang Qingfeng, Chai Yizhong, Chen Kangmin

2010, 31(2): 26-31.

Abstract(22) PDF(1)

Abstract:
Experimental methods, such as SEM, TEM and chemical phase analysis, were used to study the effect of hot rolling parameters on the microstructure and properties of Ti microalloyed steel produced by compact strip production.The results show that the yield strength and tensile strength of steel were 825 MPa and 895 MPa respectively when finish rolling temperature 880℃ and coiling temperature 620℃.Large amount of nanometer TiC particles existed in steel, and the precipitation strengthening effect of these particles achieved to 150 MPa.The precipitation of titanium carbides was inhibited and precipitation strengthening effect of nanometer particles reduced significantly as coiling temperature was decreased to 580℃.The change of coiling temperature had prominent effect on the precipitation of secondary phases in steels, and the grain size of steel strips was influenced by the change of rolling and coiling temperature.Comprehensive role of the two factors induced fluctuation of strength and toughness of Ti microalloyed steel.

Application of Thermodynamics on Reaction of Carbochlorination of Titania-rich Slag in Molten Salt Chlorination

Ju Dianchun, Yan Dingliu, Li Xiangyang, Ma Enquan, Zang Yingbo, Li Junqiang

2010, 31(2): 32-36.

Abstract(26) PDF(1)

Abstract:
It is the major factor that combustion reaction of the return of oxygen in chlorine with petroleum coke affecting the temperature of molten salt chlorinator by calculation and analysis of carbochlorination thermodynamic of all oxides of titania-rich slag, temperature stability controlling is the key to further improve the operational efficiency of molten salt chlorinator;the thermodynamics trends of carbochlorination of titania-rich slag suggest that all of the oxides would be chlorinated into chloride during 900~1 500 K, while Al₂O₃ and SiO₂ in particular are very limited in fact, the order of carbochlorination of all oxides is determined and the chlorination rate of TiO₂ and SiO₂ is the same.So in terms of thermodynamics it is so hard to low the rate of chlorination of SiO₂ further to reduce the content of Si in TiCl₄.

Thermodynamic Analysis on Oxidative Roasting of High Titanium Slag

Lu Hui, Xie Gang, Yu Xiaohua, Tian Lin, Hou Yanqing, Xie Hongyan

2010, 31(2): 37-41.

Abstract(21) PDF(1)

Abstract:
The changes of phase structure and chemical compositions in high titanium slag are studied by oxidative roasting experiment in this paper.Furthermore, the thermodynamic behavior of each component of high titanium slag in the high temperature roasting process is discussed.The result indicated that most of black titanium stone phase and anatase turn into rutile in the process of oxidative roasting at 1 000℃ temperature.The thermodynamic laws on oxidative roasting of high titanium slag is investigated, the theory basis of dealing with high titanium slag is provided, it is important for improving conventional treatment technology of high titanium slag.

Thermodynamic Calculation of Microalloyed Precipitation in Austenite Region for Fe-C-N-Al-Ti-V Steel

Chang Lizhong, Yang Haisen, Li Zhengbang

2010, 31(2): 42-48.

Abstract(23) PDF(1)

Abstract:
A thermodynamic model of the microalloyed elements precipitation in austenite region for Fe-C-N-Al-Ti-V steel has been established.The computing results show that vanadium can precipitate from the austenite as long as the amount of nitrogen and vanadium can be increased although the solubility of V (CN) is high.When the nitrogen content in the steel is higher, effect of carbon on vanadium precipitation is slight.Even though increasing the amount of vanadium, nitrogen and carbon, V (CN) precipitates at the lower temperature of austenitic mainly too.Because of the great solubility of V (CN) in the austenite which is different from the Nb (CN), the lower reheating temperature can be adopted before rolling and so the smaller initial grains can be gained.

Water Modeling on Gas Blowing in Tundish and Slag Entrapment

Wang Haiqi, Bao Yanping, Tang Dechi

2010, 31(2): 49-52.

Abstract(23) PDF(1)

Abstract:
According to tundish prototype at steel work, the water model with linear scale ratio 1:3 of model and prototype has been established.Fluid flow behavior and entrapment phenomenon at the interface between slag and metal in tundish with gas curtain were studied by water model, the effect of gas flow rate and the distance of gas travel in fluid on slag/metal interface was surveyed.In normal moulding conditions, to avoid slag entrapment, the critical gas flow rate is 0.14 m³/h, and to avoid slag blow hole, the critical gas flow rate is 0.10~0.12 m³/h, if it exceeds the critical gas flow, the slag blow hole will expand at larger speed.

Numerical Simulation of Temperature Field in the Process of Wearing Water-cooled of Angle Steel

Yin Xiangguang, Ren Jitang, Xin Xiaobing

2010, 31(2): 53-57.

Abstract(17) PDF(1)

Abstract:
The prediction model of temperature field in the process of wearing water-cooled of angle steel was set up using ANSYS finite element analysis software.In the process of wearing water-cooled of the angle steel, it's thermal boundary conditions were studied, the finite element numerical simulation was carried out and distribution of temperature field and variation were analyzed, in which numerical simulation results are in good agreement with the experimental results.The results provide a theoretical basis and practical guiding significance to reveal the wearing water-cooled law of angle steel, developing device of wearing water-cooled of angle steel and cooling technology.

Influence of Microstructure and Mineral Compositions of Vanadium-titanium Sinter on its RDI

Wang Wenshan, Ren Gang, Lv Qing, Sun Yanqin

2010, 31(2): 58-62.

Abstract(25) PDF(1)

Abstract:
Vanadium-titanium sinter has a complex liquid composition, which exists the phenomena such as low productivity, poor drum strength and serious RDI.In this paper, aiming at the serious RDI of Chengde steel sinter, we study the mechanism of RDI through analyzing the mineral compositions and microstructure of vanadium-titanium sinter.It will provide a favorable theoretical basis for controlling RDI.

Study on Clogging Mechanism of Submerged Entry Nozzle for Continuous Casting of Ferritic Stainless Steel Containing Ti

Zhang Hejia, Chen Weiqing, Wu Difeng, Zheng Hongguang

2010, 31(2): 63-66,76.

Abstract(17) PDF(1)

Abstract:
The types of inclusions and the phases of clogging of submerged entry nozzle in 00Cr18Ti stainless steel were investigated by optical microscope and scanning electron microscope(SEM), and meanwhile the mechanism of nozzle clogging was studied.The results showed that a lot of titania inclusions existed in molten steel, and some of them adhered and precipitated to the interface of nozzle, which led to clogging.The formation of mass titania inclusions was depressed, and the phenomenon of titania clogging of submerged entry nozzle was avoided by controlling the contents of w_[Al]-w_[Ti] below the equilibrium curve of competitive oxidation reaction between [Al] and [Ti], that is w_[Ti]/w_[Al]^4/3 less than 273.55.

Influence of Compositions and Process on Behaviors of Axle Steel for Railroad Vehicles

Yang Xiongfei

2010, 31(2): 67-71,87.

Abstract(17) PDF(1)

Abstract:
The effects of chemical compositions, deformation temperatures and cooling rates on mechanical properties and microstructures of axle steel for railroad vehicle was investigated through comparison tests and thermo-mechanical simulation tests.Then, based on the front experiment, a new steel with 0.40% C-0.08% V-0.019% Ti was developed successfully.The new steel displays excellent tensile properties and invisible sensitivity to two different deformation temperatures applied.However, the cooling rates have great influence on microstructures of steel, which implies proper heat treatment is necessary for eliminating mixed grains inevitably occurred in practical product of steel axle.

Study on Corrosion Resistance of 200 Series Stainless Steel

Qi Da, Li Jing, Dong Li, Yu Jian

2010, 31(2): 72-76.

Abstract(18) PDF(1)

Abstract:
Corrosion resistance of 200 and 304 series stainless steel has been studied by means of potentiodynamic polarization curves in 3.5% NaCl solution and salt spray test.Resultsshow that pitting corrosion resistance and uniform corrosion resistance of 304 series stainless steel is much better than that of 200 series.Pitting potential of 201, 202 and 304 series stainless steel in 3.5% NaCl solution are-32, -22, 312 mV and corrosion rate are 0.007 1, 0.006 2, 0.002 6 mm/a respectively.

Study of Parameters and Techniques for Chromium-electrodeposited Texturing

Tan Yong, Yu Xiaozhong, Liu Changsheng, Sun Jie

2010, 31(2): 77-80.

Abstract(19) PDF(1)

Abstract:
The textured rollers produced by the conventional techniques have some disadvantage performances that include rapid roughness attenuation, limited use time and more pits on roller surface, which are not suitable for the formation of roughness on the cold roller surface.In order to increase the service life of the textured roller, a technique process was designed to electroplate chrome on the IF steel surface.The experiment of DC superimposed pulse was performed to obtain the certain roughness chrome textured and hemisphere-shaped chrome coatings.From the results, it was shown that the roughness and hardness of coating obtained by electroplating was 3.79 μm at 850 mA/cm² and 1 000 HV respectively.

Ultra-high Basicity Sintering Production Practice of Pangang

He Muguang, Zhang Yixian, Rao Jiating, Li Yuhong

2010, 31(2): 81-87.

Abstract(25) PDF(1)

Abstract:
Through Panzhihua V-Ti magnetite concentrate ultra-high basicity sintering production practice, the characteristics of ultra-high basicity sintering production are explored.The process should strengthen the use of quick lime and activity of ash, improve the agglomerate ratio of solvent, and take thick material layer and the principle of slow-speed machine, and the ratio of grain size of less than 3 mm for coke and anthracite can be controlled between 70% to 80%, FeO content of sintering ore can be controlled about 7.7%, Suitable moisture is between 7.2% to 7.3%.At the same time, the improvements on the burden distribution of a magnetic roller and the fuel secondary sub-plus and pairs of oblique igniter furnace are carried out, which will create conditions for improving the technical and economic indices of the high basicity sintering.The results showed that sintering crystallization conditions are improved, mineral compositions are optimized, metallurgical performance is improved, and the strength of sinter is improved.It should be noted that production of ultra-high basicity sintering greatly impact on the stability index of sinter, in particular, the R₀ stability rate of No.1 and No.2 period sinters has declined by 4.43 and 3.09 percentage points, the stability rate of TFe content of sinter decreased by 2.1 and 2.46 percentage points, which needs further technical breakthrough.

Optimizing Capability of Mould Flux to Improve the Surface Quality of Billet for Cold Forging Steel

Yang Hao, Tang Ping, Sun Wei, Wang Kaizhong, Wu Jian, Xu Jian, Zhang Jiexin

2010, 31(2): 88-92.

Abstract(44) PDF(1)

Abstract:
Hook type of oscillation mark was the primary problem about surface quality of strand which was used to product 35K cold Forging steel.The reason that induced hook type of oscillation mark was the poor lubrication of mould flux.On one hand, hook type of oscillation mark would make surface defects on strand, such as inclusion, crack and hypodermal pore.On the other hand, it would produce the phenomenon of nonuniform microstructure because of the poor heat transfer which induced huge austenite grain and developmental microstructure on the surface of strand.It finally caused crack of cold forging steel.Therefore, through optimizing capability about physical property and chemical composition of mould flux and improving the lubrication capability of flux, the hook type of oscillation mark had been removed and the nonuniform microstructure phenomenon on oscillation mark had been controlled.In the end, it provided eligible strand for subsequent rolling process.

2010 Vol. 31, No. 2