钢铁钒钛

Regression Relations of Hydrolysis Parameters for Rutile Titanium White Preparation via Short Sulfate Process

Tian Congxue

2017, 38(4): 1-5. doi: 10.7513/j.issn.1004-7638.2017.04.001

Abstract(67) PDF(3)

Abstract:
The rutile TiO₂ white pigment was prepared via short sulfate process of diluted thermal hydrolysis with self-generating crystal seeds using unenriched low concentration of industrial titanyl sulfate solution as titanium source. The regression relations and influences of the hydrolysis parameters,including preadding water volume ratio,aging and hydrolysis time on the structure,particle size distribution and pigment properties of metatitanic acid and rutile TiO₂ white pigment were investigated. The hydrolysis parameters significantly influence the number and quality of the initial formed nuclei,the crystal growth and aggregation,and eventually determine the pigment properties of the products. There exist mathematical correlations between the hydrolysis parameters and products crystal structure,particle polydispersity index,and pigment properties. The optimal hydrolysis parameters are 0.123 of the pre-adding water volume ratio,29.05 min of the aging time and about 2.6 h of hydrolysis time after the second boiling.

Experimental Study of Perparing VN from Ammonium Metavanadate by One Step Method

Zhu Jun, Cheng Guopeng, Wang Huan, Wang Bin, Liu Xinyun

2017, 38(4): 6-11. doi: 10.7513/j.issn.1004-7638.2017.04.002

Abstract(138) PDF(9)

Abstract:
Based on the thermodynamic calculation,the process of preparing vanadium nitride by carbon thermal reduction was explored by analyzing the thermogravimetric-differential thermal experiment,and the effect of carbon ratio of raw material and reaction temperature on the phase and composition of the products was investigated in this paper.The results show that the nitrogen content of the nitrided product is the highest when the carbon ratio is the stoichimetric. The process of preparing vanadium nitride by one step is the simultaneous coupling reaction of carbon thermal reduction and nitriding of vanadium oxide.

Electrochemical Deposition of Titanium Ions in Molten Salts

Zhu Fuxing, Qiu Kehui, Sun Zhaohui, Mu Tianzhu, Deng Bin

2017, 38(4): 12-18. doi: 10.7513/j.issn.1004-7638.2017.04.003

Abstract(217) PDF(9)

Abstract:
The electrochemical deposition behaviors of titanium ions in titanium extraction by molten salts electrolysis were investigated.Different electrolytes were firstly prepared by adjusting the ratio of TiCl₄ to titanium sponge in NaCl-KCl melts then the electrochemical deposition behaviors of titanium ions were analyzed in the obtained electrolyte systems. According to XRD of the electrolytes of low valence titanium,the main products were TiCl₂ and NaCl-KCl-TiCl₂ electrolyte system can be formed when the mole ratio of TiCl₄ to Ti was 1:2 at 993 K in NaCl-KCl melts,while the TiCl₂ and K₃TiCl₆ with 2.57 of average valence and NaCl-KCl-TiCl₂-K₃TiCl₆ electrolyte system were obtained when the mole ratio of TiCl₄ to Ti was 2:1.The results of cyclic voltammetry for the electrolyte systems mentioned above indicated that the reduction course of titanium ions was Ti²⁺→Ti in NaCl-KCl-TiCl₂ influenced by diffusion with 2.93 × 10^-5cm²/s of diffusion coefficient and it was two steps of Ti³⁺→Ti²⁺and Ti²⁺→Ti in NaCl-KCl-TiCl₂-K₂TiCl₆ system.The morphology of titanium powder obtained in NaCl-KCl-TiCl₂ system was dendrite large particles,and with increase of current density and decrease in concentration of titanium ions the particle size of products decreased.Fine and porous titanium powder was prepared in NaCl-KCl-TiCl₂-K₂TiCl₆ melts.

Effects of Metal Ions Doping on Properties of Nano-TiO₂ by Ionic Liquid Assisted Synthesis

Cui Shuhua

2017, 38(4): 19-23. doi: 10.7513/j.issn.1004-7638.2017.04.004

Abstract(57) PDF(1)

Abstract:
Transition metals （Cr,Fe,Ni and Zn） doped TiO₂ nanoparticles were synthesized by sol-gel method using 2-hydroxyimidazole formate ionic liquid as microstructure control reagent.The prepared samples were calcined at 500 ℃,and then were characterized by BET,XRD and DRS,etc. The photocatalytic properties of the obtained TiO₂ were also tested with Acid Blue 92 as simulated pollutants.The results show that transition metals doped TiO₂ nanoparticles have a higher specific surface area and smaller particle size in comparison with those of pure TiO₂,and the absorption spectrum of transition metals doped TiO₂ shifts to visible light. According to the degradation of Acid Blue 92 in aqueous solution under UV irradiation,the photocatalytic activities of transition metal ions doped TiO₂ nanoparticles are enhanced significantly.

Study on the Organics Pretreatment of Crude Titanium Tetrachloride with High Content of Vanadium for Vanadium Removal

Zhou Li

2017, 38(4): 24-28. doi: 10.7513/j.issn.1004-7638.2017.04.005

Abstract(103) PDF(4)

Abstract:
The crude titanium tetrachloride obtained from the titanium recovering process of Pangang blast furnace slag has a high vanadium content （4.9‰）,which cannot be effectively removed by the existing process with aluminum powder. To solve this problem,this paper proposes a pretreatment method by organics for vanadium removal before the following process of vanadium elimination by aluminum powder,and the main technological parameters influencing vanadium removal efficiency,e.g. the species and dosage of organics,temperature and time,were optimized. The results show that the vanadium content of crude titanium tetrachloride can be decreased to 1.667‰ after the pretreatment at 45 ℃ for 30 min with 3% mineral oil. The slurry produced in pre-processing has a good settling property,and the titanium tetrachloride after separation of the slurry meets the feedstock requirements of vanadium removal process by aluminum powder. Moreover,the slag obtained by drying the slurry of vanadium removal has a high recovery value since it contains a high concentration of vanadium（8.06%）.

Effect of Cooling Ways on Compositions and Acidolysis of Titanium Slag

Song Bing, Liu Juan, Xiao Jun, Han Kexi, Li Kaimao

2017, 38(4): 29-33. doi: 10.7513/j.issn.1004-7638.2017.04.006

Abstract(65) PDF(3)

Abstract:
The cooling treatment of titanium slag has an important influence on the subsequent titania pigment production.In this paper,the effect of cooling method for titanium slag,including granulating,water cooling and air cooling,on the compositions,phase and acidolysis performances of titanium slag was investigated.It is found that the titanium sesquioxide content in the slags is decreased using the cooling treatments mentioned above,of which the granulated slag has the lowest content of Ti₂O₃.The main phases are TiO₂ and （FeMg）_xTi_yO₅ in the cooled slags.The crystal form of TiO₂ is rutile in granulated slag but anatase in water cooling or air cooling slag.The acidolysis rate of cooled slags is all less than that of the industrial titanium slag. The acidolysis rate is 90.61% and 92.46% for the water cooled slag and air cooled slag,respectively.However,the acidolysis rate of granulated slag is only 74.72%,about 20% less than that of industrial titanium slag.

Electrochemical Formation of Titanium-aluminum Alloys from Ti₂O₃ In-situ Chloridized by AlCl₃ in Chloride Melts

Yan Beilei

2017, 38(4): 34-39. doi: 10.7513/j.issn.1004-7638.2017.04.007

Abstract(87) PDF(1)

Abstract:
This article investigated the feasibility of chlorination of titanium oxides to TiCl₃ in liquid phase using AlCl₃ as chlorinating agent in the molten NaCl-KCl system.Compared with the chlorination results of TiO,Ti₂O₃ and TiO₂ and based on the thermodynamic analysis of reactions of AlCl₃ with TiO,Ti₂O₃ and TiO₂,Ti₂O₃ was selected for chlorination to TiCl₃.Different electrochemical testing means were used to investigate the alloying process of Al（Ⅲ） and Ti（Ⅲ） on the molybdenum electrode and the feasibility of preparation of TiAl₂ and TiAl₃ alloys by codeposition.Alloys were analyzed using XRD and SEM.Thus,it is feasible to prepare Ti-Al alloys by molten salt electrolysis directly.

Reaction Kinetics of Vanadium-aluminum Alloy Preparation by Thermite Method

Jing Han

2017, 38(4): 40-43. doi: 10.7513/j.issn.1004-7638.2017.04.008

Abstract(68) PDF(3)

Abstract:
The reaction kinetics of preparation of vanadium-aluminum alloy by thermite method was studied by DSC.Reaction activation energy was obtained by Flynn-Wall-Ozawa equation,and Kissinger equation was used to verify the reliability of the calculated reaction activation energy by Flynn-Wall-Ozawa equation,showing an almost consistent value for both of the methods. Other kinetics parameters were obtained to establish the kinetics equation for the thermite reaction by Kissinger-Crane equation using the average value of activation energy calculated by Flynn-Wall-Ozawa and Kissinger equation as input parameter.The results show that the average apparent activation energy,reaction order and frequency factor for the reaction of vanadium-aluminum alloy preparation by thermite method is 386.5 kJ · mol^-1,1.04 and 3.361×10³⁰min^-1,respectively.

Morphology Evolution of Pyrolysis Products of Ammonium Metavanadate in Air

Fu Xiaoming, Sun Hu, Yang Zaizhi

2017, 38(4): 44-47. doi: 10.7513/j.issn.1004-7638.2017.04.009

Abstract(247) PDF(23)

Abstract:
Based on the TG-DSC analysis for the thermal decomposition of ammonium metavanadate（NH₄VO₃,AMV for abbreviation） in air,The phases of the final products for the thermal decomposition of AMV in air and the morphologies of the pyrolysis products of AMV at the inflection point temperatures in corresponding DSC curve were characterized by X-ray diffraction （XRD） and scanning electron microscope （SEM）,respectively.The results show that there are two steps in the thermal decomposition process of AMV in air.There is （NH₄）₂O·2V₂O₅ as mediate phase during the first step,and the transition from amorphous to crystal state of the pyrolysis products of AMV in air happens in the second step. The morphologies of the pyrolysis products of AMV in air are mainly irregular flakes in different periods,but the thickness of vanadium pentoxide （V₂O₅） is relatively homogeneous.

Influence of α-contaminant Layer on the Microstructure and Properties of Ti-6Al-4V Titanium Alloy Casting

Chen Rong, Liu Zhaohua, Zhang Dafu, Zhou Xiaoting

2017, 38(4): 48-52. doi: 10.7513/j.issn.1004-7638.2017.04.010

Abstract(86) PDF(2)

Abstract:
The microstructure,oxygen and hydrogen content,nano hardness trend of α-contaminant layer on the surface of Ti-6Al-4V titanium alloy by vacuum smelting（ZTC4 for abbreviation）were investigated,and the effects of α-contaminant layer on the tensile properties of ZTC4 titanium alloy were also analyzed.The results show that α-contaminant layer has a thick lamellar structure with the maximum thickness of 0.28 mm.Compared with the those of the heart zones of ZTC4 alloy,the oxygen content and average hardness of the α-contaminant layer respectively increases by 1.64 and 0.94 times while its hydrogen content decreases by 1 time.The α-contaminant layer has a significant effect on the tensile properties of ZTC4,and the yield strength,tensile strength,elongation and section shrinkage of ZTC4 respectively decreases by 14.2%,12.5%,20% and 35% in comparison with those of the alloy without α-contaminant layer.The hard and brittle α-contaminant layer is formed on the surface of the alloy by dissolving oxygen atoms,which is difficult for deformation under the tensile load,and then the macroscopic fracture sources are formed in the weakest zones of alloy and quickly expand to the matrix resulting in brittle cleavage fractures in the alloy finally.

Effects of Sintering Process on Properties of Titanium Alloy Auto Parts

Zhang Bin

2017, 38(4): 53-57. doi: 10.7513/j.issn.1004-7638.2017.04.011

Abstract(46) PDF(1)

Abstract:
Ti-6Al-4V-0.5In titanium alloy auto parts samples were prepared by discharge plasma sintering at various sintering temperatures and sintering pressures,and the effects of sintering process on the wear resistance and impact property of the samples were studied.The results show that with the increase of sintering temperature and sintering pressure,both the wear resistance and impact property of the samples first increase and then decrease.The optimal sintering temperature and sintering pressure are 875 ℃ and 45 MPa,respectively.

Alloy Elements Optimization of High Strength Al alloy Plate for Automobile

Zeng Maoyan

2017, 38(4): 58-62. doi: 10.7513/j.issn.1004-7638.2017.04.012

Abstract(73) PDF(2)

Abstract:
The extruded 5754 aluminum alloy high strength plate specimens for automobile with various contents of alloying elements vanadium and strontium had been used to carry out tensile and thermal fatigue tests.The results show that vanadium and strontium additions could improve the tensile properties and thermal fatigue property of the plates.The optimized content of alloying elements vanadium and strontium was 0.6% and 0.4%,respectively. Compared with the plate without vanadium,the tensile strength and yield strength of the plate with vanadium of 0.6% increased by 16% and 43%,and the average width and length of main crack decreased by 36% and 35%,respectively.Compared with the plate containing vanadium without strontium,the tensile strength and yield strength of the plate with strontium of 0.4% increased by 8%and 17%,and the average width and length of main crack decreased by 73% and 65%,respectively.

Research of the Occurrence State of the Main Impurities in Panxi Ilmenite

Ye Endong, Wu Xuan

2017, 38(4): 63-68. doi: 10.7513/j.issn.1004-7638.2017.04.013

Abstract(29) PDF(3)

Abstract:
Through the research of the mineral structure of vanadium-titanium magnetite and the mineral process technology of titanium concentrate in Panxi area,the distribution of the main elements and the state of the impurity elements were concluded by deeply profiling of the titanium concentrate using XRD and SEM.Panxi titanium concentrate based on the lattice of metatitanic acid iron（FeO·TiO₂）,is a solid solution with Mg and Mn,etc.The main impurity elements,such as Si,Ca,Mg,Al,Fe and Ti,etc.,are dissolved as one or more types of oxide,in silicate which is associated with ilmenite.According to different purposes,the deeply graining and adjusting the parameters of separation technology for ilmenite concentrate were put forward to produce high quality ilmenite concentrate for realizing high value-added utilization.

Study on the Characteristics and Stability of Coarse Steel Slag Aggregate

Xing Linlin, Yang Zhigang

2017, 38(4): 69-73. doi: 10.7513/j.issn.1004-7638.2017.04.014

Abstract(111) PDF(2)

Abstract:
From the view of feasibility study on steel slag as coarse aggregate of concrete,morphology,chemical composition and mineral composition and other characteristics of steel slag had been investigated through the XRF,XRD and SEM microscopic observation. Different coarse aggregates had been prepared with addition of 100%,75%,50%,25%,and 0% steel slag.Based on the determination method for steel slag stability,autoclaved powder ratio of resulted coarse aggregated had been measured.The corresponding concrete test block made of the different aggregate had been test in terms of its compressive strength at different ages and its stability after 28-day aging.The results show that the steel slag can be used as the coarse aggregate of concrete.With the increase of the proportion of steel slag,the stability of the concrete is reduced,the optimum content is 50%,and the corresponding powdering rate is about 4.7%.

Study on Preparation and Performances of Microcrystalline Foam Glass from Titanium Tailings

Shu Mingyong, Yin Haiying

2017, 38(4): 74-81. doi: 10.7513/j.issn.1004-7638.2017.04.015

Abstract(41) PDF(1)

Abstract:
Using Panzhihua ilmenite tailings as raw materials and borax as fluxing reagent,the microcrystalline foam glass was prepared successively through melting,water quenching,foaming,microcrystallization and annealing processes.The effects of foaming agent species and amount,foam stabilizer amount,foaming temperature and time,microcrystallization temperature and time,on the apparent density,compressive strength and water absorption of the obtained microcrystalline foam glass were investigated.From SEM of the prepared microcrystalline foam glass,it presents an inflated porous structure with interconnected closed-irregular bubbles in the interior.It is shown that the microcrystalline foam glass having 1.8~2.2 mm of pore diameter,1.31 g/cm³ of apparent density,16.7 MPa of compressive strength and 11.3% of water absorption can be obtained by foaming at 840 ℃ for 20 min and microcrystallization at 550 ℃ for 90 min with addition of 2% CaCO₃ and 5% Na₃PO₄·12H₂O as foaming agent and foam stabilizer,respectively.

Study on High Temperature Composite Adhesive Mechanism of Dust Cold Consolidation Pellet

Li Shiqin, Ning Xiaojun, Zhang Jianliang, Liu Zhengjian, Yuan Xiang, Wang Fei

2017, 38(4): 82-88. doi: 10.7513/j.issn.1004-7638.2017.04.016

Abstract(54) PDF(1)

Abstract:
The cold consolidation pellets were made by bag ash,electric furnace ash,coke powder and cement,and the high temperature self-reduction experiment was carried out on the pellet.Pure cement samples had been used for differential thermal experiments.Finally,the self-reduction experiment was carried out on the cold consolidation pellet made of pure solid iron oxide,graphite powder and pure alumina powder without adding binder.The mechanism of high temperature composite bonding of dust and cold consolidation pellets was analyzed by detecting the compressive strength,scanning electron microscopy and energy spectrum analysis.The results show that the strength of the cold consolidation pellets at low temperature is mainly determined by the cement.With the temperature increasing,the cement gradually failed,after 1000 ℃ in the metal iron began form,and become the main binder phase. Unmelted slag material has a negative impact on the formation of metal iron crystal,when its content excessing 15% it will have a significant impact on the formation of crystal.

Determination of Silicon,Iron,Molybdenum,Potassium and Sodium in Vanadyl Oxalate by ICP-OES

Cheng Yong

2017, 38(4): 89-93. doi: 10.7513/j.issn.1004-7638.2017.04.017

Abstract(72) PDF(4)

Abstract:
The analyzing method directly and simultaneously detecting silicon（Si）,iron（Fe）,molybdenum（Mo）,potassium（K） and sodium（Na） with the content of 0.001%~0.100% in vanadyl oxalate（VOC₂O₄） using inductively coupled plasma atomic emission spectrometry（ICP-OES） was established.The influences of matrix effects,spectral interferences and continuous background superposition in the system with high concentrations of vanadium ion and oxalate coexistence,on the testing were studied,and the conclusions that the matrix effects and continuous background superposition of VOC₂O₄ have a negative interference to K and Na but a positive disturbance to Si,Fe and Mo in the system were obtained.Matrix matching coupled with synchronous background correction was employed to eliminate the matrix effects of VOC₂O₄.Based on the spectral interference from matrix elements vanadium（V） and carbon（C）,the candidates of spectral lines disturbed by the spectra of matrix components were selected,from which the appropriate analyzing spectral lines,background correction areas and operation conditions of spectrometer for the tested elements were determined.The results show that the RSD is less than 10% with-0.000 3%~0.000 3% of background equivalent concentration,0.000 1% ~0.000 3%（0.005~0.015 mg/L） of element detection limit and 0.001%~0.010% of element content,while the RSD is less than 5% with 0.010% ~0.050% of element content.The recovery rate is 91.6% ~109.4%,and the testing results are in accordance with those by ICP-MS.

Properties of Ultra-fine Grained V-microalloyed Dual Phase Steels

C. P. Scott, F. Fazeli, B. Shalchi, I. Pushkareva

2017, 38(4): 94-104. doi: 10.7513/j.issn.1004-7638.2017.04.018

Abstract(59) PDF(6)

Abstract:
The effect of vanadium microalloying on the microstructure and properties of a high strength dual phase steel was studied.Compared to the Fe-0.186C-1.5Mn-0.3Si-0.008 N reference alloy it was found that the addition of 0.14 %wt.V resulted in:①A very significant ferrite grain size refinement in the cold rolled and annealed state.②During continuous annealing the initial ferrite to austenite transformation kinetics was strongly retarded.③On slow cooling the ferrite start transformation temperature was slightly increased but the pearlite and bainite transformations were suppressed,resulting in a net overall increase in hardenability.④Undissolved cementite was observed at intercritical annealing temperatures ≤740 ℃.⑤After annealing at 750 ℃/180 s intense V（C,N） precipitation（mean diameter 7.4 nm） was observed in the ferrite phase whereas precipitates were scarce in martensite （austenite） and much larger （mean diameter 13.4 nm）.⑥The increase in tensile strength with martensite fraction of the reference alloy was ~16 MPa/%. However,the vanadium alloy showed a much lower sensitivity to martensite content（~4MPa/%） due to grain refinement and selective strengthening of the ferrite phase,and actually became softer than the reference steel at martensite fractions ＞ 45%.At iso-tensile strength the fracture strain and hole expansion coefficient of the V alloy showed some improvement over the reference steel,however the gains were much smaller than those obtained by tempering.

Research and Development of Titanium Microalloyed High Strength Steel

Huo Xiangdong, Xia Jinian, Li Liejun, Peng Zhengwu, Chen Songjun

2017, 38(4): 105-112. doi: 10.7513/j.issn.1004-7638.2017.04.019

Abstract(80) PDF(5)

Abstract:
In this paper,the development history of titanium microalloyed high strength steel is briefly reviewed. The research and development status of titanium microalloyed high strength steel expounded in detail,more attention is paid to the precipitation behavior of nano-carbide （stain-induced precipitation and interphase precipitation） in titanium microalloyed high Strength Steel above 700 MPa,and the development trend of titanium microalloying technology is also analyzed,aiming at perfecting physical metallurgy theory of Ti microalloying high strength steel and providing some guidance for the development and industrial application of titanium microalloying high strength steel.

Effect of TiO₂ Content on Melting Behavior of Ilmenite Powder

Kang Qingfeng, Zhang Jianliang, Liu Hao, Liu Zhengjian, Liu Donghui, Zhang Yapeng, Wang Yaozu

2017, 38(4): 113-117. doi: 10.7513/j.issn.1004-7638.2017.04.020

Abstract(37) PDF(1)

Abstract:
In order to make better use of all kinds of iron ores,the effects of TiO₂ content on melting behavior of titanium-containing ilmenite powder were studied by the seat drop method. The results showed that the sample shrinkage process was divided into two stages:slow and fast steps.The melting temperature of iron ore powder showed a increasing trend with the increase of TiO₂ content.However,the melting temperature of iron ore powder was lower when the TiO₂ content was 1%.The melting time of iron ore powder showed an increasing trend with the increase of TiO₂ content. Sintering fuel consumption can not be reduced when TiO₂ content is too high.Taking into account the characteristic temperature and melting time of the ilmenite powder,the TiO₂ content should be controlled less than 3%.

Comparative Study on Softening-melting Properties Between Vanadium Titanium sinter and Ordinary sinter

Yang Wenkang, Yang Guangqing, Xing Hongwei, Li Xiaosong

2017, 38(4): 118-122. doi: 10.7513/j.issn.1004-7638.2017.04.021

Abstract(29) PDF(1)

Abstract:
The difference of performance index between vanadium titanium sinter and ordinary sinter was studied under simulated blast furnace in the laboratory. The experiment result indicates that the softening start temperature of vanadium titanium sinter are higher than that of ordinary sinter; the softening end temperature and dripping temperature of vanadium titanium sinter are lower than that of ordinary sinter; the pressure of vanadium titanium sinter are high and the gas permeability of vanadium titanium sinter are poor.

Research Status of the Influence of the Blast Furnace Slag Microstructure on its Metallurgical Properties

Yan Zhaozhao, Zhang Shuhui, Zhang Shuqing, Dong Xiaoxu, Qie Yana

2017, 38(4): 123-129. doi: 10.7513/j.issn.1004-7638.2017.04.022

Abstract(66) PDF(2)

Abstract:
Blast furnace slag belongs to multiple sillicate system and can meltat high temperature. The material microstructure determines its macroscopic properties.This paper summarizes the research status of blast furnace slag microstructure,and analyzes their influence on slag fluidity and desulfurization ability.The chemical composition of blast furnace slag is mainly divided into modification and formation. Network structure in slag is mainly made up of silicon oxygen tetrahedron. CaO and MgO play their role as the network modification. With the increase of CaO and MgO content,the free oxygen ions concentration is increased in the slag,which destroys the silicate network structure and reduces the polymerization degree of complex anionic,thus the viscosity of slag reduces. But the excess alkalinity or MgO content also enhances the content of high melting point mineral in the slag,which makes the slag viscosity increase.Al₂O₃ and TiO₂ plays different roles in slag with different contents of the two material. Within a certain range of content,Al₂O₃ and TiO₂ acting as network modification,make the viscosity of slag reduce. Along with the increase of the content of Al₂O₃ and TiO₂,they convert to network formation and make slag viscosity increase,which worsens the liquidity of the slag. As MgO content or slag basicity increase,the complex ionic group is suffered,which improves the desulfurization reaction. But when the content of MgO is too high,the high melting point material increases,which leads to worsen the fluidity and lower desulfurization ability. Through studying the microstructure of blast furnace slag deeply,the relationship between the metallurgical performance and chemical composition of slag can be understood easily,which provides the theoretical basis for determining reasonable slag system.

Prediction Model of Desulfurizer Consumption Based on BP Neural Network and Regression

Zheng Yi, Zuo Kanglin

2017, 38(4): 130-134. doi: 10.7513/j.issn.1004-7638.2017.04.023

Abstract(47) PDF(1)

Abstract:
The effect of hot metal temperature,hot metal amount,initial sulfur content,end-point sulfur content,etc,on the consumption of Mg powder was analyzed.It is found out that the consumption of magnesium powder increased with elevation of hot metal temperature,and obviously increased with decrease of end-point sulfur content by amplitude enlarge gradually.In order to reduce cost,the depth of desulfurization should be controlled properly.The desulfurizer consumption prediction model based on BP neural network and regression was established to ascertain appropriate powder consumption. The BP neural network was the main output and the regression model was used to constrain output range. The prediction model was realized on-line control without human intervention,and good application effect was achieved.If deviation between end-point sulfur content and aim sulfur content was within [-0.001 5%,0.001 5%],the coincidence rate of end-point sulfur content reached 90.85%,so the model could effectively achieve the control of the sulfur content after desulfurization.

Study on Rheological Properties of Fluorine-free Continuous Casting Mould Powder

Wang Xingjuan, Wu Binbin, Zhu Liguang, Fan Yapeng, Tian Kuo

2017, 38(4): 135-139. doi: 10.7513/j.issn.1004-7638.2017.04.024

Abstract(29) PDF(1)

Abstract:
In this paper the transition temperature and viscosity of mould powder with different B₂O₃,TiO₂ and CaF₂ had been measured,and the corresponding lnη-1/T curve had been plotted.Viscous flow activation energy had been calculated through fitting method.The effect of CaF₂,TiO₂ and B₂O₃ contents on the rheology characteristics of mould powder had been investigated.The reasonable TiO₂ and B₂O₃ contents for appropriate rheological properties of mould powder without fluorine are less than 9% and 7%,respectively.

Study on the Stability of Inclusion Adsorption on Refractory Wall

Wang Yufei, Zhao Dingguo, Gao Ming, Wang Shuhuan

2017, 38(4): 140-146. doi: 10.7513/j.issn.1004-7638.2017.04.025

Abstract(62) PDF(3)

Abstract:
The interaction between inclusion and refractory wall and the stability of inclusion in the continuous casting nozzle had been studied,and the inclusion adhering model had been developed. Analysis results show that when the inclusions are attached to the refractory wall,the inclusions exert positive adsorption force from refractory wall.The force on the parallel wall direction is mainly related to the inclusion radius,which increases with the radius of inclusions.The force of the inclusions on vertical wall direction increases with the inclusion of radius and wetting angle. The stability of the wall inclusions decreases as radius of inclusions increase.When the radius of the inclusions is greater than 4 μm,the adhesion stability of different inclusions change,and the inclusions stability from high to low level are Al₂O₃＞TiN ＞MgO ＞SiO₂.When the inclusions are attached to the inclusions bottom of the refractory wall,the force of inclusions on the vertical wall direction decreases slowly with the increase of the roughness,and increases with the size of inclusions.

Effects of Mn Content on Microstructure and Mechanical Properties of Fe-Mn Alloy

Yang Feng, Cao Wenquan, Dong Han

2017, 38(4): 147-154. doi: 10.7513/j.issn.1004-7638.2017.04.026

Abstract(207) PDF(2)

Abstract:
Effects of Mn content on microstructure and mechanical properties in Fe-Mn alloys containing various Mn ranging from 3% to 12% （mass%） have been studied by scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,electron back scattered diffraction（EBSD）,tensile and Charpy impact tests.When Mn content is in the range of 3%~9%,with the increase of Mn content,the volume fraction of high temperature transformation products declines while the amount of low temperature transformation products increases,leading to the increased yield strength and tensile strength but decreased uniform elongation and total elongation.When Mn content increase to 12%,about 2% ε-martinsite and 1% austenite presents in the microstructure and they are easily transform to α-marteniste during early stage of straining,resulting in the increased uniform and total elongations and the illusion of decreased yield strength because of transformation plasticity.Since increased Mn concentration can decline the cohesion of grain boundaries,the impact energy of Fe-Mn alloys decreased sharply with the increase of Mn content.In order to obtain better comprehensive mechanical properties,the Mn content should be lower than 7% or higher than 12% to introduce more metastable austenite.

Experimental study of Gas-solid Decarburization process of 1.5 mm Fe-C Alloy Ribbon

Chen Pengfei, Ai Liqun, Li Qiang, Li Yaqiang, Liu Xinliang

2017, 38(4): 155-159. doi: 10.7513/j.issn.1004-7638.2017.04.027

Abstract(39) PDF(1)

Abstract:
In order to investigate the decarburization law of 1.5 mm thick iron-carbon alloy strip,an iron carbon steel strip with initial carbon mass fraction of 3.2% was used and placed into a decarburization furnace under weak oxidizing atmosphere created by Ar-H₂-H₂O mixed gas and heated. The samples were heated to 1 293 K,1 353 K and 1 413 K with holding time of 10~50 minutes respectively for the decarburization treatment via gas-solid reaction.the sample.The results show that the decarburization reaction is a approximate first-order reaction,and the activation energy is 111.9 kJ/mol.The decarburization temperature has a significant effect on the decarburization effect.The final carbon content as function of holding time can be expressed as w_t=3.2e^{((0.196 12-1.62×10^-4T)t}.

Analyses and Control of Scale on Ferrite rolled Ti-IF Steel Sheets

Wang Jiangong, Li Rui, Liu Ruiguang, Gao Yue, Zhou Xun, Xia Yinfeng, Li Lang, Kang Yonglin

2017, 38(4): 160-163. doi: 10.7513/j.issn.1004-7638.2017.04.028

Abstract(50) PDF(1)

Abstract:
In this paper the surface scale formation of ferrite rolling to Ti-IF steel on hot semi-continuous rolling line had been discussed.Through the SEM and XRD experiment analysis the composition and microstructure of the scale along the steel strip width direction under processes of ferrite rolling had been determined.It is found out the ferrite rolling process is benefit for surface quality control.

2017, 38(4): 164-166.

Abstract(46) PDF(1)

Abstract:

2017 Vol. 38, No. 4