钢铁钒钛

Technology Analysis on Fluidized Bed Hydrogen Metallurgy at Low Temperature

CAO Chaozhen, GUO Peimin, ZHAO Pei, PANG Jianming

2008, 29(4): 1-6.

Abstract(16) PDF(2)

Abstract:
Low-temperature fluidized bed hydrogen metallurgy was studied by thermodynamics calculation in this paper.Traditional hydrogen metallurgy had the disadvantages of high gas consumption and low productivi- ty.The thermodynamics calculation indicates that under the condition of ore powder preheated,the consump- tions of hydrogen are 6 394 m³ and 3 189 m³,when the gas temperature drop is 100 K and 200 K respectively, while the gas consumptions are 4 367 m³ and 2 195 m³ for the part-hydrogen metallurgy（containing 30% CO）.Accordingly the primary consumption of reducing gas of part-hydrogen metallurgy is less than that of the exclusive-hydrogen metallurgy.Part-hydrogen metallurgy should be developed preferentially considering our gas resource.To reduce the gas consumption,the multistage fluidized bed reactor should be applied and the ore powder should be preheated for fluidized bed hydrogen metallurgy processes.The hydrogen metallurgy process of fast reduction of fine ore at low temperature can improve the gas efficiency and the reduction speed rate remarkably.

Preparation of Nano-TiO₂ by Stripping Precipitation Method and Photocatalytic Performance

ZHANG Lingyun, GUAN Hangmin, LI Hansheng, ZHANG Dongxiang

2008, 29(4): 7-13.

Abstract(20) PDF(1)

Abstract:
Precursor of nano-TiO₂ was prepared through stripping precipitation method with D2EHPA diluted by tetrachloride carbon as an extractant,and ammonia and ammonia-alcohol aqueous solution as a re-ex- tractant and precipitator.This process was optimized by controlling mass transport process on the interfaces of microemulsions.Nano-TiO₂ obtained was characterized by SEM、XRD、Zeta potential devices.The result showed that catalytic performance was distinctly influenced by lowering temperature and concentration of ammo- nia aqueous,increasing concentration of ethanol auxiliary agent and varying calcinating temperature of TiO₂ sample.By stripping precipitation with ammonia and ammonia-alcohol,the optimum caleinating temperatures of TiO₂ were adjusted at 350℃and at 450℃respectively.The temperature and the optimum concentration of ammonia aqueous were 17.5℃and 1:5 respectively.The higher concentration of auxiliary agent was more beneficial to forming smaller and more uniform TiO₂ particles.Compared with sol-gel method,directing pre- cipitation method and stripping precipitation method with ammonia,this study showed that nano-TiO₂ pre- pared by stripping precipitation with ammonia-alcohol had not only a small and uniform grain,but also a high efficient photocatalytic activity,and the removal efficiency of methylene blue illuminated for 60 min with TiO₂ by stripping precipitation with ammonia-alcohol was above 85 %.

Study on Formaldehyde Degradability of Metal-doped Nano-TiO₂

WU Jianchun, HUANG Wanxia, SHI Ruicheng

2008, 29(4): 14-17.

Abstract(26) PDF(1)

Abstract:
The formaldehyde degradability by nanometer TiO₂ that is metal-doped compound was studied.The result shows that the formaldehyde degradability and the visible light absorbency are improved by the V-doped nanometer TiO₂.The nanometer TiO₂ of 0.5 % Fe+0.3 % V doped has better photocatalytic activity than single V-doped nanometer TiO₂.And it can degrade 85 percent formaldehyde after 24 hours.

Application of the Large Industrial Microwave Oven in Pre-production of Vanadium Nitride Product

DING Yu, ZHOU Jicheng, FU Huihua

2008, 29(4): 18-21.

Abstract(25) PDF(1)

Abstract:
The developing process and application of the industrial microwave oven with the largest heat power and stove size in china developed independently for vanadium nitride production have been introduced.Using the industrial microwave oven,we have produced vanadium nitride product,the standard of which is higher than the foreign Nitrvan12 product.There are a lot of remarkable advantages for the process,such as short heating time,lower power consumption,easier operation and control.Through the developing of this type of microwave oven,we have accumulated valuable engineering experiences for designing and manufacturing large industrial microwave sinter ovens.

Preparation of Titanium Carbonitride from Panzhihua Ti-bearing Blast Furnace Slag Using Magnetic Separation

YI Xiaoxiang, LI Yawei, YANG Dabing

2008, 29(4): 22-25.

Abstract(22) PDF(1)

Abstract:
The preparation of titanium carbonitride from Panzhihua Ti-bearing blast furnace slags which contains 20 %～26 % TiO₂ is described.The process contains two main stages,which consists of reducing carbonization and nitriding of titanium oxide of slags,and iron as a carrier can realize the titanium carbonitride and the gangue mineral separation with the magnetic separation.The concentrate of Ti（C,N）is above 36.46 %,and the recovery of TiO₂ is up to 43.77 %.

Development and Application of Refining Desulfurizing Agent Based on Panzhihua Iron and Steel Co.Blast Furnace Slag Extracted Titanium

LI Youqi, KE Changming, GAN Lin, LIU Xiao, LI Yousheng, LI Nan

2008, 29(4): 26-31.

Abstract(23) PDF(1)

Abstract:
A new refining desulfurizing agent with good desulphurization property but without CaF₂ was synthe- sized using Panzhihua Iron and Steel Co.blast furnace（BF）slag extracted titanium as main materials and ac- tive calcium oxide as addition agent.The effects and action mechanism of CaO content on the phase composi- tions,melting performance of the slag system and the desulfurizing ratio of steel samples were investigated.At the same time,the sulphur capacity and optical basicity of slag with different content CaO were given by theo- retical calculation.The results show that active calcium oxide can not only increase violently the desulfurizing thermodynamic parameters such as sulphur capacity and optical basicity of the slag,but also can improve the melting performance.When the CaO content of the slag reaches 60 percent,the optical basicity and sulphur capacity of the slag are 0.781 and 15.8×10^-3respectively,the desulphurization property of the slag is the best.The sulphur content of the steel can decrease from 42.4×10^-6to 7.95×10^-6,the desulphurization ra- tio and sulphur distribution coefficient are 81.2 % and 192.6 respectively.A new technology of comprehensive utilization of BF slag bearing titanium is developed through this paper.

Effect of Vanadium on the Microstructure and Properties of YQ450NQR1 Higher Strength Weathering Steels

LIU Qingchun, ZHONG Hua, ZHENG Zhiwang

2008, 29(4): 32-36.

Abstract(19) PDF(1)

Abstract:
The target-oriented researches on the vanadium-containing YQ450NQR1 high strength weathering steels were conducted in this paper.Methods such as optical microscope,high resolution electron microscope, phase analyzing,and so on were used to investigate the effect of vanadium on microstructure and the behavior of vanadium precipitates on the hot-roiling samples.The relationship between the amount of vanadium precip- itates and properties was analyzed.It has been found that the microstructures of test steels are composed of block ferrite and pearlite,vanadium is obviously precipitated from steel,the precipitates consists of VN or V （C,N）particles primarily.It is also obviously that the yield strength of steel can be raised after adding vana- dium into steel which is close correlated with the content of nitrogen.The content of vanadium can be brought down so long as higher precipitation proportion of VN is obtained.

Study on the Improvement of Slab Equiaxed Crystal Ratio by Electric Pulse Acted on Liquid Steel in Continuous Casting Mould

GU Wuan, CANG Daqiang, ZHANG Kaijian, ZONG Yanbin, CHEN Lin, CHEN Haijun, GU Longjian, YANG Subo, YANG Senxiang

2008, 29(4): 37-41.

Abstract(34) PDF(1)

Abstract:
The improvement of slab equiaxed crystal ratio by electric pulse on liquid steel in continuous casting mould of Panzhihua steel No.1 slab was studied.The improvement of slab equiaxed crystal ratio was analyzed according to energy consumption per ton steel by electric pulse on liquid steel in continuous casting mould.The slab equiaxed crystal ratio was heightened up to 48% at most,average to 15% with electric pulse than without electric pulse while the speed,cast,superheat,mould cooling regime and second cooling regime were in the same conditions.

Research on Secondary Cooling Technology for Continuous Casting of 360 mm× 450 mm Bloom

CHEN Yong, YANG Subo, ZHU Miaoyong

2008, 29(4): 42-47.

Abstract(20) PDF(1)

Abstract:
In view of surface longitudinal crack,intermediate crack and center line crack on 360 mm×450 mm continuous casting blooms,the secondary cooling scheme employed in the continuous bloom caster was opti- mized,which included increasing the specific water flow,adjusting the water flow distribution among the sec- ondary cooling zones,so the surface quality and internal quality of bloom improves obviously.The practical op- eration shows that the ratio of longitudinal crack defect due to serious intermediate crack on blooms is decreased from 53.85% to 0.30%,the ratio of center looseness≤1.0 is increased from 74.87% to 99.53%,the free center line crack is increased from 68.83% to 82.77%,the free intermediate crack is increased from 82.95 % to 90.98 %.

Effect of Annealing Microstructure and Texture on Magnetic Properties for the Low Grade Cold Rolled Non-oriented Silicon Steel by CSP Process

ZHU Tao, SHI Lifa, CHEN Qian

2008, 29(4): 48-51,57.

Abstract(28) PDF(1)

Abstract:
The distribution and composition of the texture and microstructure in two different the low grade cold roiled non-oriented silicon steel have been investigated using optical microscope and X-ray diffraction ODF analysis methods.The influences of texture types and microstructure on the magnetic properties are discussed. The result shows:as the content of（Si+Al）increase,grain size is bigger and iron loss is reduced;with in- creasing of orientation in density of the {100}＜0vw＞and a orηfiber texture,magnetic properties is in- creased,and the intensity of {111}＜112＞component decreasing causes magnetic flux increasing obviously.

Fe-VC Composite and 45^# Steel TIG Welding

YANG Tinggui, WANG Yisan, CHENG Fengjun, GAO Jian, ZHOU Zhao

2008, 29(4): 52-57.

Abstract(29) PDF(1)

Abstract:
The study on welding performance of Fe-VC composite and 45^# steel has been investigated,with tungsten inert gas welding（TIG）,and an austenitic stainless welding wire（ER309L）as filler metal.The mi- crostructure and phase of the welded joint were studied with the help of SEM and XRD;the distribution of al- loy elements composition in weld was analyzed by EDAX;the tensile strength of welded joint was tested ac- cording to national standard.The result shows that the firm joint could be obtained when composite and 45^# steel were fused each other;the alloy elements were gradient distributed in weld;the all cracking zones of ten- sile samples were located in composite,which proved that the applied welding method,filler metal and weld process can satisfy the welding techniques of these two different kinds of materials.In addition,the quality of weld is reliable.

Determination of Reduction Parameters of Soft Reduction in High Carbon Steel Continuous Casting Blooms

LIU Wei, LIU Liu, HE Ping

2008, 29(4): 58-62.

Abstract(18) PDF(1)

Abstract:
Soft reduction technology that is known to be one of the effective ways to minimize segregation is used widely in high carbon steel continuous casting blooms.Determination of reduction parameters is very im- portant to the soft reduction technology.Based on the theoretical analysis and the product experience of some plants,it will be found that an optimum soft reduction zone is solid fraction ranged from 0.2 to 0.8 and the to- tal reduction amount ranged from 4 mm to 8 mm.Optimum application of the soft reduction process will lessen V shape segregation and the center carbon segregation of the bloom and also make a remarkable improvement in the macrostructure of it.

Objective Analyzing of Thin Slab Continuous Casting and Rolling Technology

LIAO Jianyun

2008, 29(4): 63-66.

Abstract(22) PDF(1)

Abstract:
There are distinct differences in slab thickness,casting speed,cast structure and on-line continu- ous rolling between thin slab casting and conventional process.The thin slab process has some advantages of stronger cooling strength,shorter product line and lower consuming.In the meantime,it also has some disad- vantages of not so good surface quality and small range adaptability in production.In recent years,the technol- ogy of thin slab continuous casting and rolling has been developed very much in China and more than ten prod- uct lines have been built.But there is different estimating about this process.In this paper,it is analyzed about the advantages and disadvantages of microstructure,precipitation of compound and adaptability of thin slab in order to objectively and practically evaluating the process of thin slab continuous casting and rolling.

Research on the Process of Improving the Molten Steel Quality of Low Alloy Steel

ZENG Jianhua, CHEN Tianming, CHEN Yong, YANG Subo, JIANG Nanhong, YANG Senxiang

2008, 29(4): 67-71.

Abstract(15) PDF(1)

Abstract:
In view of the actual situation of Panzhihua Iron ＆ Steel（Group）company（PZHISC）,in order to controlling compositions of ladle slag,a high basic refining slag was added to ladle during the steel being tapped,a modifier was added to ladle after the steel was tapped,also a small number of high basic refining slag and 0.30～0.60 kg aluminum pill per ton steel were supplemented in LF furnace.And the blowing argon time was extended by 6 min after LF refining.The removal conditions of inclusions were improved by these technical measures,the quality of molten steel of low carbon steels was improved substantially.The average total oxygen content is 14.69×10^-6,the average sulphur content is 0.007%,[N]is less than 50×10^-6,non-metallic inclusions of type-B and type-C are less than before,the vast majority of non-metallic inclusions of type- A and type-D both are 0.5 grade in the test slab of low alloy steel.

Effects of Solid Fuel Types and Ratio on Sintering Process and Metallurgical Property of V-bearing Titaniferous Magnetite Sinter

ZHANG Zhenfeng, Lü Qing, WANG Wenshan, ZHANG Shuhui, LIU Zengxun

2008, 29(4): 72-76.

Abstract(24) PDF(1)

Abstract:
Based on the material condition of Chenggang sintering state,the effects of solid fuel types and ratio on sintering process and metallurgical property of agglomerate with vanadium were researched.The results show that with the white coal instead of coke powder as solid fuel,the magnetite,silicate and glassiness content in agglomerate decrease,while hematite and calcium ferrite content increase,which make cold mechanical strength and low temperature reduction degradation of agglomerate improve.High solid fuel ratio is not proper for Chenggang sintering.The optimal ratio of coke powder served as the solid fuel is about 5 %;when the white coal serves as solid fuel,the ratio is about 5.5 %～6%.In conclusion,the white coal should be used as solid fuel in Chenggang,while the optimal FeO content of agglomerate with vanadium is about 7%.

Analysis on the Blackening Surface of the Low Carbon Aluminum-killed Steel

LIU Yuzhang, DAI Xuecheng, ZHANG Xinpeng

2008, 29(4): 77-80.

Abstract(17) PDF(1)

Abstract:
After low carbon aluminum-killed steel was annealed in the bell annealing furnace,the filiform blackening surface of the cold-rolled steel sheet was investigated,and its micro-morphology,elemental composition,structure and generation mechanism was analyzed and discussed.The studies show that the phe- nomenon is the result of that carbon was crystallized on the sheet surface during the recrystallization annealing. The black substance causing the surface blackening is graphite.

2008 Vol. 29, No. 4