钢铁钒钛

Numerical Simulation of Injection of Coke Oven Gas with Oxygen Enrichment to the Blast Furnace

Gao Jianjun, Guo Peimin

2010, 31(3): 1-5.

Abstract(22) PDF(1)

Abstract:
The blast furnace is divided into two zones of hot zone and solid furnace charge zone.Based on the material and heat balance, according to lager-scale blast furnace production data, the mathematical model of injection of coke oven gas to blast furnace is established.The calculation results show that when coke oven gas injection volume is increased by 50 m³, ironmaking CO₂ emissions will reduce 5%, while theoretical flame temperature is decreased by 35℃.If keep the theoretical flame temperature same as large-scale blast furnace, with the increase of amount of coke oven gas injection, CO₂ emissions of ironmaking are larger than that without considering theoretical flame temperature, but it can always decrease CO₂ emissions obviously.

Study on Extracting Vanadium from Stone Coal Calcine by Pressure Alkaline Leaching

Xiao Chao, Xiao Liansheng, Ding Wentao

2010, 31(3): 6-9.

Abstract(15) PDF(1)

Abstract:
Considering that extracting V₂O₅ from coal-stone by "roasting-alkali leaching" process exist some serious problems such as abundant alkali consumption, long leaching time and leaching solution with high impurity content and so on, the experiment of extracting V₂O₅ from stone coal calcine by pressure alkaline leaching was investigated, and effects of dosage of sodium hydroxide, liquid-solid ratio, leaching time, recycle leaching on the vanadium leaching were studied.The results showed that when sodium hydroxide 3.5% of ore calcine weight, the ratio of liquid-solid 1.5:1, leaching temperature 180℃, leaching time 2 h, the leaching rate of vanadium in stone coal is 86%, mass ratio of vanadium and silicon is 0.65, and pH of the leaching solution is 12.1.High-pressure alkaline leaching process with the advantage of high leaching rate of vanadium but low leaching rate of other impurities, provides a new way for extracting V₂O₅ from stone coal.

Extraction of Low Grade Vanadium Ore by Acid Leaching Process

Li Xin, Wang Yi, Zhu Jun

2010, 31(3): 10-14.

Abstract(14) PDF(1)

Abstract:
According to the problems existing in current process for extracting vanadium, the screening classification of a low-grade vanadium ore were investigated, and the acid leaching process for vanadium extraction from the vanadium ore concentrated for tailing discarding was researched based on the mineralogy and physical dressing.The parameters in leaching process had been analyzed and optimized in experiments, and the suitable process conditions were determined including grinding fineness, the concentration of sulfuric acid, leaching temperature, liquid-solid ratio and leaching time.The leaching rate of vanadium can be over 90% under the optimum conditions.

Study on the Reduction of 1～3 mm Iron Ore Powder by CO in Fluidized Bed

Pang Jianming, Guo Peimin, Zhao Pei

2010, 31(3): 15-19,24.

Abstract(17) PDF(1)

Abstract:
The reduction behavior of ore powder by co in homemade kg-scale fluidized bed was studied.The reduction degree of the sample increases and the utilization ratio of gas decreases when the reaction lasts longer time, which indicates that the reaction is faster at the beginning of reduction, while it becomes slower in latter process.The higher the reaction temperature, the higher the utilization ratio of gas and the reduction degree are, but the difference of utilization ratio among the different temperatures becomes smaller with time.The utilization ratio of gas can reach about 8% and the reduction degree 80% for 20 min reduction at 850℃, which shows under high temperature the reduction reaction by CO is very fast.The higher the reaction temperature, the higher the apparent reaction rate constant is, but the difference of apparent reaction rate constant among the different temperatures becomes bigger.The increase of reduction degree with gas velocity increase performs quite good linearity, which shows under high temperature even higher velocity of reducing gas can be used to improve the productivity of reactor when CO is used as reducing gas.With the increase of charge height, the metallization ratio and the reduction degree decrease, but the utilization ratio of gas increases.The apparent activation energy of the reduction of 1~3 mm iron ore powder by CO is about 59.11 kJ/mol in the fluidized bed experiment.

Research on the Non-reactive Mold Powder for High Aluminium Steel

Wang Huan, Tang Ping, Wen Guanghua, Yu Xiong

2010, 31(3): 20-24.

Abstract(12) PDF(1)

Abstract:
The SiO₂ component of the traditional mold fluxes can easily been deoxidized by the Al contained in liquid high aluminium steel.So a series of mold fluxes containing lower SiO₂ was designed to solve this problem, and their viscosity-temperature curves and melting points were tested.The results showed that these viscosities and melting points are suitable to industrial application.The thermodynamic analysis and the steel-slag interfacial reaction experiment showed that the mold fluxes of which SiO₂ content is less than 6% can be called non-reactive mold powder.

Effect of Annealing on Low-carbon and Low-silicon Non-oriented Silicon Steel Produced by TSCR

Kuang Yuanhui, Li Jianjun, Yue Erbin, Chou Shengtao, Shi Zhe

2010, 31(3): 25-29,49.

Abstract(31) PDF(1)

Abstract:
The effect of annealing at 850~1 000℃ on structure, precipitate, texture and magnetic properties of 0.5 mm low-carbon and low-silicon cold-rolled non-oriented silicon steel produced by TSCR has been researched.Meanwhile, the impact of annealing at 950℃×5 min and 950℃×7 min has been compared.The results show that the grain size increased and became more uniformity with increasing annealing temperature and prolonging annealing time.So the iron loss decreased and the magnetic induction increased.The main precipitates were coarse AlN and mulriple precipitation of MnS.There was no less than 0.1μm small dispersion of AlN and MnS.The surface of annealed cold rolled sheets was relatively strong γ fiber texture which is harmful to magnetic induction, while the γ fiber texture weakens obviously in the center of it.The {001}〈010〉 cubic texture enhanced and {110}〈001〉 gauss texture basically remained unchanged in the center of annealed cold rolled sheets.

Study on Flaking Resistance of Hot-dip Galvanizing Coating

Guo Taixiong, Jin Yongqing, Zhang Yong, Liu Chunfu

2010, 31(3): 30-33.

Abstract(14) PDF(1)

Abstract:
For the issue of flaking of the hot-dip galvanizing coating during drawing, the microcosmic characteristics of the coatings have been analyzed and experiments have been done to investigate the influence of coating thickness, Al content and steel substrate strength on its flaking-resistance.The results show that the fact of flaking is that the coating partially flaked off at the position far away from interface of steel substrate and coating, and not entirely flaked off from steel substrate because of poor adhesion.The flaking resistance of coating decreases with the increase of coating thickness and steel substrate yield to strength ratio, and increases with the increase of Al content in coating at the same experimental conditions.

Research on High Temperature Mechanical Properties of GCr15 Bloom

Li Jianquan

2010, 31(3): 34-37.

Abstract(21) PDF(1)

Abstract:
The high temperature mechanical properties of GCr15 bloom, such as yield strength, tensile strength, hot elasticity and hot ductility, have been detected by thermal-tensile tests using a Gleeble-1500D system respectively.The thermal-tensile tests show that the yield strength, tensile strength, elasticity modulus and plasticity modulus of steel decrease with the increase of test temperature and the bloom has easily plasticity deformation affected by external force in high austenite temperature, then has crack defect.The second embrittlement zone of GCr15 bloom occurred in the temperature range 725℃to 800℃.

Influence of Turbulence Controller on Inclusion Removal in T-type Tundish

Wang Lei, Wang Qian, Chen Yongshu, Zhang Guoxing

2010, 31(3): 38-43.

Abstract(18) PDF(1)

Abstract:
The influence of turbulence controller on inclusion removal was studied by means of water modeling experiments and numerical simulation.The moving trajectories of inclusion particles in tundish were compared with and without turbulence controller.By use of the turbulent controller, the molten steel can easily flow from the bottom to the surface of liquid steel, thus, the short circular flow is eliminated and the surface flow can be developed, and it's helpful to remove the inclusion.The combination of turbulence controller and dam showed a better result in removing inclusion in tundish.

Study on Optimization of Flow Control Devices in Two Strand Slab Continuous Casting Tundish

Li Jiao, Li Jingshe, Yang Shufeng, Sun Liyuan, Lin Xiaochuan, Bai Ruiguo

2010, 31(3): 44-49.

Abstract(26) PDF(1)

Abstract:
Based on the similar theory, water model of two strand slab continuous casting tundish was established in the ratio of 1:3.The inner structure of tundish is optimized by the combination of weirs and dams with different heights and positions.The experiment results show that the minimum residence time in the modified tundish increases from 83 s to 97 s, the mean residence time increases from 296 s to 432 s, the dead zone volume decreases from 46% to 21% and all the microscopic fluctuations decrease from 0.04 ms/cm to 0.025 ms/cm, the goal of optimizing the inner structure of the tundish has been achieved.

Research on Cleanliness of 27SiMn Steel Produced by BOF-LF-CC Process

Sun Liyuan, Li Jingshe, Tang Haiyan, Li Jiao

2010, 31(3): 50-53,58.

Abstract(16) PDF(1)

Abstract:
The cleanliness of 27SiMn tube billet produced by BOF-LF-CC process in a domestic steel mill is studied by the way of sampling systematically and comprehensive analysis.The results show that the quantity of microinclusions decreases from 35.0 to 8.4 per square millimeter after LF.The quantity of total oxygen and inclusions contents increases obviously in tundish.The average total oxygen content is(24~30)×10^-6 in round billet, and macroinclusion in it is 0.487 mg/kg.The main factors affecting the steel cleanliness are revealed based on research results, such as reoxidation caused by burning oxygen and pouring unstably and slag entrapment in mold.Then some measures of improvement process are proposed pointedly.

Research on Slag-conglomerating Agent of Pure Magnesium Desulphurization in Hot Metal

Chen Yongshu, Wang Qian, He Shengping, Wang Lei

2010, 31(3): 54-58.

Abstract(31) PDF(1)

Abstract:
The physical and chemical properties of industrial desulfurizing slag and slag-conglomerating agent were studied in the present work.It was found that the desulfurizing slag has an exceptionally high melting temperature and is distributed widespread on the hot metal surface in granular forms, and industrial slag-conglomerating agent with high melting point and high viscosity.Therefore, it is difficult to remove desulphur ization slag by wiping of the slag from hot metal.In that case, resulphurization takes place in the LD process, especially in ultra-low sulphur steel production.According to the characteristics of industrial slag-conglomerating agent, slag-conglomerating agent with low meting point and high viscosity was developed.The results show that:the ratio is 2:5, which can be able to play a very good effect of conglomerating slag.

Influence of Cooling Speed on Microstructure of Nb-V Microalloyed High Strength Steel

Chen Zhenye, Chen Zigang, Qin Xiuying

2010, 31(3): 59-62,74.

Abstract(17) PDF(1)

Abstract:
The experiments of a microalloyed high strength steel under heating, heat preservation and cooling at different speeds were conducted on the thermal-simulator of THERMECMASTOR-Z.And the microstructure was observed by Zeiss Axioplan2 universal metallographic optical microscope.The effects of cooling speed on microstructure and phase transformation of the microalloyed high strength steel were analyzed.It has been found that the temperature points and temperature range of phase transformation decrease with the increase of the cooling speed.The ferrite grain will be refined and the ferrite amount will decrease with the increase of cooling speed.At the same time, deformation can promote phase transformation.

Effect of Finishing Rolling Temperature on Microstructures and Mechanical Properties of Steel Strip for Engineering Mechanism

Zhang Kaihua, Ye Xiaoyu, Liu Yong, Yang Feng

2010, 31(3): 63-67.

Abstract(14) PDF(1)

Abstract:
Effect of finishing rolling temperature on microstructures and mechanical properties of steel strip for engineering mechanism was studied by means of optical microscopy, SEM, TEM, tensile property testing and impact toughness testing.The results show that tensile strength and yield strength of testing steel decrease and elongation increase with the decrease of finishing rolling temperature.The value of low temperature impact toughness with high finishing rolling temperature is very low, while it increases a lot as finishing rolling temperature decrease.The microstructure of testing steel with high finishing rolling temperature consists of ferrite and a little pearlite, which is inhomogeneous.While with intermediate and low finishing rolling temperatures, the microstructure of it contains ferrite and pearlite, and the ferrite grain is regular.The microstructure of testing steel with low finishing rolling temperature is more homogeneous than that with intermediate finishing rolling temperature.Strip-like or rod-like multicarbides M₃C exist on the grain boundary of ferrites with high finishing rolling temperature.

Experimental Study on Marginal Extension of Slab Corner Transverse Crack after Rolling

Liu Yang, Gu Linhao, Li Zhanjun, Wang Wenjun, Lv Yanchun, Wang Haibao, Jiang Zhongxing

2010, 31(3): 68-74.

Abstract(14) PDF(1)

Abstract:
Both laboratory and industrial experiments are carried out to test the marginal extension of slab corner transverse crack after rolling.It is found that with the increase of slab rolling thickness, the extension of corner crack along width direction of cast slab will develop.Comparatively the corner transverse crack of thin rolling slab is less and can be driven out.Safe edge trimming width of slab with rough edge is 35 mm.

Technical Study of Hot-rolled Steel Strips for Automobile Beam

Jiang Yingyu

2010, 31(3): 75-79.

Abstract(11) PDF(1)

Abstract:
By designing reasonable chemical compositions and studying rolling technology, Bayi Iron & Steel Company have developed B510L and B550L hot-rolled steel strips for automobile beam bearing titanium and columbium.The tensile strength and weldability and cold deformation capability of rolled steel can meet the requirement of relevant standards and customers.The ductile-brittle transition temperature of rolled steel is less than -40℃.The non-metallic inclusions in steel show the distribution of dispersion of globosity and the question of anisotropy is resolved preferably.

Influence of New Zealand Sea Sand Proportioning Ratio on Metallurgical Properties of Vanadium-titanium-bearing Sinter of Cheng Steel

Lv Qing, Wang Wenshan, Jin Yuchen, Li Fumin, Gao Feng

2010, 31(3): 80-83,87.

Abstract(30) PDF(2)

Abstract:
The influences of New Zealand sea sand proportioning ratio on vanadium-titanium-bearing magnetite sintering process and metallurgical properties of sinter were determined.The results show that the vertical sintering speed and utilizing coefficient all increase with increasing sea sand ratio.The grain size distribution of sinter is improved, and mechanical strength and low temperature reduction degradation property don't increase apparently.There are good softening Characteristics in experimental conditions.The composition and structure of sinter are complicated.The sea sand proportioning ratio in the Cheng Steel should be controlled 5%~10%.

Practice of Reducing Inclusion in Q235 Slab for Chuanwei

Li Liang, He Shengping, Zhang Guoxing

2010, 31(3): 84-87.

Abstract(10) PDF(1)

Abstract:
Utilizing the methods of nitrogen oxygen analysis, sample-electrolyzing and spectrum analysis, cleanliness of casting slab of Q235 was surveyed under present process in Chuanwei, and the reason of low cleanliness of molten steel was analyzed, and the smelting process for Q235 was optimized.The results show that utilizing slag washing operation, controlling soft blowing time and strength, and reducing slag amount of ladle, large inclusions and T[O] in steel decreased dramatically, cleanliness of steel was significantly increased.

Study on Cyclic Utilization of Converter Dust-removal Resource for Panzhihua Steel

Liu Shihong

2010, 31(3): 88-92.

Abstract(18) PDF(1)

Abstract:
Based on the characteristics of converter dust-removal ash in Panzhihua Steel, synthetic slag forming medium, final slag regulator, both of which are used in semi-steel converter steelmaking, and coolant used in vanadium extraction are developed.The effects of synthetic slag forming medium and final slag regulator on terminal oxidation of semi-steelmaking, converter' splash, consumption of iron and steel materials as well as converter dephosphorization and so on are analyzed.The using ways of converter dust-removal resource are expanded.Then, it can make dust-removal resource get much better utilization in Panzhihua Steel and decrease pressure in environmental protection.

2010 Vol. 31, No. 3