钢铁钒钛

Study on The Preparation of Nano-TiO₂ by Liquid-phase Hydrolysis

Sun Tianyu, Zhang Shuangquan, Pan Tingting

2009, 30(4): 1-5.

Abstract(17) PDF(1)

Abstract:
Nano-titanium dioxide powder that has good dispersivity and small particle size was prepared by liquid-phase hydrolysis with the materials of titanium tetrachloride and n-octanol.The factors which influence the properties of titanium dioxide were researched by X-ray diffraction and transmission electron microscope.The results show: when the calcination temperature rises,the nano-TiO₂ particles become larger,and the dispersivity is worse;the crystal phase changes from anatase phase to rutile phase at higher temperature;the calcination time affects slightly on the nano-TiO₂ particle size and the crystal phase,but it affects intensely on the dispersivity of nano-TiO₂;when the titanium tetrachloride concentration increases,the nano-TiO₂ particle size becomes smaller,but the dispersivity becomes worse;and when the hydrolysis temperature increases,the nano-TiO₂ particle size becomes larger,and the dispersivity becomes worse.

Study of Preparation of V⁵⁺ Doped Titanium-bearing Blast Furnace Slag and Its Antibacterial Capability

Wang Hui, Xue Xiangxin, Yang He, Li Shuxian

2009, 30(4): 6-10.

Abstract(14) PDF(1)

Abstract:
V⁵⁺ doped titanium-bearing blast furnace slag as a kind of antibacterial materials based on photocatalysis was prepared by high temperature solid-state method.Using escherichiacoli,staphylococcusaureus,albicans candida and bacilluscercus as experimental bacteria,effects of strains and doping amount on antibacterial capability were studied under fluorescent lamp.Surface topography and phase transformation of absent were analyzed through SEM and XRD.The result showed that the best antibacterial capability was obtained against albicans candida,and will increase with doping amount of V⁵⁺ increasing;MIC measured by agar pervasion method was 2.5%;the antibacterial capability decreased in a small range after being treated by brine and ethanol.

Effect of TiB₂ Addition on the Tensile Properties of In-situ Synthesized TiB₂/Ferrous Matrix Composites

Cao Hui, Liu Ying, Li Binghong, He Lin, Li Jun, Gao Shengji

2009, 30(4): 11-15.

Abstract(25) PDF(1)

Abstract:
The effect of TiB₂ on the tensile properties of in-situ synthesized TiB₂ /Ferrous matrix composites was investigated by means of X-ray diffraction (XRD), optical microscope (OM), scanning electron microscope (SEM) and materials testing system.The results show that the TiB₂ particles are uniformly distributed in the α-Fe matrix, and it demonstrates remarkable reinforcing effect on the matrix.With the increase of TiB₂ addition, the tensile strength and yield strength of the composites also increase, but the elongation decline.

Effects of Rolling Process on Microstructures and Properties of the Commercial Pure Titanium

Chen Xiqiang

2009, 30(4): 16-20.

Abstract(17) PDF(1)

Abstract:
The commercial pure titanium slabs were rolled using current rolling device,microstructure and morphology at the head and end of these slabs were studied by optical microscope,and results show that microstructure and morphology of the head are similar to ones of the end,i.e.having a little retained β phase in the serrated lamella of α phase in core microstructure,the smallest equiaxed grains in the four corners' microstructure,smaller deformed α grains in the middle part microstructure of the slab surface.TEM analyses showed that a lot of dislocations and more precipitated phases and twins microstructure,but no any lath distributing structure,occur in α phase of the rolling microstructure.It is found by XRD that stronger deformation texture occurs in rolling microstructure.Both the transverse and longitudinal tensile properties of rolled slab were tested in this paper.Transverse yield strength and tensile strength of slab are stronger than those of longitudinal direction.

Application of VN Alloy in High-carbon Wire and Rod of WSWRH82B

Shen Jinlong, Tan Zhiguang, Xia Yanhua, Han Bin

2009, 30(4): 21-26.

Abstract(13) PDF(1)

Abstract:
The application of VN alloy in WSWRH82B high-carbon wire and rod is introduced,the effect of VN Microalloying and different cooling processes in lab on microstructure and properties of WSWRH82B is mainly studied;the reasonable content of V and N elements is gotten for 2 000 MPa grade PC steel strand.Moreover,the precipitates behavior of vanadium and nitrogen is observed during the cooling course,and the mechanism of precipitates is analyzed.

Effects of Microalloy Element on Microstructure and Mechanical Properties of 700 MPa Low Carbon Bainitic Steel

Cao Huiquan, Yan Huicheng, Xia Zhenghai, Luo Deng, Li Guangmin, Chou Shengtao

2009, 30(4): 27-31.

Abstract(26) PDF(1)

Abstract:
The microstructure and mechanical properties of low carbon bainitic steels with different Nb and Ti content are investigated by analyzing CCT curves of 700 MPa series low carbon bainitic steel.The result shows that the increment of Ti/Nb improves the tensile and yield strength of bainitic steel.Excessive Ti content is adverse to the low temperature impact Energy.Nb 0.04%~0.05% and Ti 0.015%~0.025% are the suitable content for 700 MPa low carbon bainitic steel.Qualified mechanical properties of steel are obtained after TMCP and tempering process.

Effect of Cold Reduction Ratio on Microstructure Textures and Mechanical Property of IF Steel

Wang Minli, Zheng Zhiwang

2009, 30(4): 32-39.

Abstract(22) PDF(1)

Abstract:
Hot rolled IF steel was used to study the effect of cold reduction ratio on the microstructure textures and mechanical properties of Ti-IF and Ti+Nb-IF steel after batch annealing processes.The results showed that recrystallization of the IF steels was rudimentarily finished after batch annealing,the grain shape is pancake;and the grain size diminishes as the cold reduction ratio was increased;the strain hardening exponent n value was gradually reduced.The plastic strain ratio value(r_90°) of Ti+Nb-IF steel reached the maximum with the higher carbon content and cold reduction ratio of 70%,or with the lower carbon content and cold reduction ratio of 80%;the plastic strain ratio value(r_90°) of Ti-IF steel reached the maximum with cold reduction ratio of 70%;however,when the cold reduction ratio was increased,the textures of IF steel was stronger,then the {223}<110>、{114}<110>and {111} textures of lower cold reduction ratio were changed to {223}<110>、{111}<110>and {114}<110> textures of higher cold reduction ratio,and the textures trend toward {111} texture.

Effects of C,Cu and Mn on Hot Ductility of Oriented Silicon Steels

Dong Tingliang, Yue Erbin, Zhang Chen, Chou Shengtao, Zhao Pei

2009, 30(4): 40-44.

Abstract(21) PDF(1)

Abstract:
High temperature mechanical property of oriented silicon steel with main inhibitor Cu₂S produced by the thin slab casting and rolling was tested, comparing reduction of area and SEM of fracture surface in 600~1 300 ℃ and analyzing effects of C (0.020%~0.044%), Cu (0.18%~0.49%) and Mn (0.06%~0.16%) on hot ductility of oriented silicon steels.The results showed that hot ductility trough moved to lower temperature and higher ductility with the content of C, Cu and Mn increasing;hot ductility was improved because C and Mn enlarge γ phase;Cu can also enlarge γ phase, and then decrease of grain-boundary strength of the steel became lower and ductility was improved, because that S and Cu created Cu₂S, and Cu₂S makes fluid phase which make against hot ductility and sulfide including iron reduce, so Cu improve hot ductility.

Research on Surface Cracks of CCSD36 Ship Plate Steel

Wang Shuoming, Liu Qinggang, Li Xiuqing, Gao Ju, Zhang Caijun

2009, 30(4): 45-48.

Abstract(31) PDF(1)

Abstract:
The reason of cracks was studied by analyzing the surface crack of slabs and experimental research in this dissertation.Result shows: surface cracks on CCSD36 steel mainly result from the original slab cracks.It originates in mold and extends in secondary cooling zone and rolling.Oxidation layer along the cracks formed in high temperature makes cracks hard to be welded.A large amount of inclusions with high melting point and low plasticity,such as silicates,exist inside and around the cracks,the content of which is deviated from the normal state seriously,and brittle particles are formed.When they are captured by exterior and oxidation layer,the surface will break during being rolled,so the cracks extend or newly formed.

Numerical Modeling Study on a New Type of Swirling Flow SEN for Round Bloom Continuous Casting

Wu Yaoguang, Chen Yuanqing, Chou Shengtao, Zhao Pei

2009, 30(4): 49-54.

Abstract(26) PDF(1)

Abstract:
A new idea that the steel swirling flow in the mold is generated by adjusting the direction of jet from side holes in SEN is brought forwards, based on which a new type of multi-hole swirling flow nozzle, which is easy for machining and with simple structure, is designed.Three dimensions mathematical model is built for fluid flow and heat transfer in the round bloom continuous casting mold.The flow and temperature field are computed under traditional straight channel nozzle and the new type of swirling flow nozzle conditions.Study shows that the steel swirling flow can be formed in the mold by adjusting the direction of jet from side holes in SEN, and that the new type of swirling flow nozzle can obviously reduce the impact depth of the jet, accelerate inclusion floatation, move the heat center up, and increase the temperature on the meniscus.

Simulation on Flow Field and Temperature Field of Molten Steel in Bloom Mold with EMS

Chen Yong, Zhu Miaoyong

2009, 30(4): 55-59,71.

Abstract(33) PDF(1)

Abstract:
In order to simulate the flow field and temperature field of molten steel in 360 mm×450 mm bloom continuous casting mold,a 3-D mathematical model was presented.On this basis,the distribution of the flow field and temperature field was analyzed.Numerical simulation results show that the flow direction of molten steel streamed from submerged entry nozzle is changed from vertical downwards to horizontal rotary in effective region of electromagnetic stirring with EMS,and main region of rotary flow is formed.Upper part of molten steel in the effective region is formed into rotary flow from downwards flow of center to upward of solidification surface,then,lower part of molten steel in the effective region is formed into rotary flow from upward part of center to downward of solidification surface.Meanwhile,because of the flow direction changed from vertical downwards to horizontal rotary,the depth of molten steel streamed from submerged entry nozzle becomes shorter,axial temperature becomes lower,radial temperature becomes higher,temperature gradient at solidification surface becomes bigger,and heat transfer becomes more rapidly,which will promote the homogeneous growth of solidifying shell

Physical Simulation of Flow Field for Single Strand Tundish in Slab Continuous Casting

An Hanghang, Bao Yanping, Jin Youlin, Li Taiquan

2009, 30(4): 60-66,80.

Abstract(24) PDF(1)

Abstract:
Reasonableness of structure of the tundish of stainless steel slab casting had been studied by water model experiment.To aim at the influencing factors of flow field in tundish and the existing problems respective,flow control device was optimized through orthogonal optimization tests.The results showed the opening size of lower retaining wall is the key factor of influencing flow field.Considering RTD and flow field display synthetically,while liquid level retained stable,the insertion depth is 180 mm and the casting speed is 1.2 m/min,optimal process parameters is as follows,the distance from upper weir to ladle bottom is 375 mm,the height of upper weir is 208 mm,the distance from upper weir to dam is 575 mm,height of the dam is 100 mm,the opening of the dam is 0 mm.Compared with the prototype tundish,the flow field is improved to a great extent,average retention time is prolonged,the proportion of dead zone decreases,short circuit flow is effectively improved,molten steel becomes uniformity and inclusions clump and grow sufficiently.The results of industrial test showed that under the optimum condition of weir for tundish,purity of casting slab was greatly improved and reject rate of cold rolled sheet reduced.

Effect of Reversing Cold Rolling on Texture and Ferrite Grain Size of Steel Sheet

Guo Taixiong

2009, 30(4): 67-71.

Abstract(19) PDF(1)

Abstract:
A study on effect of reversing cold rolling on texture and ferrite grain size of DX51D(LCAK steel) and DX54D(IF steel) has been done by simulating experiment of reversing and continuous cold rolling and annealing in the laboratory.The results show that the α-rib {115} and {335} texture density of reversing rolling sample is obvious higher than that of continuous rolling,and the γ-rib {111} texture density of reversing rolling sample is equivalent with that of continuous rolling;the γ-rib {111} texture density of reversing rolled DX54D annealing sample is higher than that of continuous rolling,and its α-rib texture density is equivalent with that of continuous rolled annealing sample;the texture density of reversing rolled DX51D annealing sample is equivalent with that of continuous rolling;the ferrite grain size of reversing rolled annealing sample is less than that of continuous rolling.

Thermodynamic Analysis of the Fast Dephosphorization Process for the Hard-wire Steel

Yin Qing, Li Zhangrong, Xie Xiang, Zhao Haowen

2009, 30(4): 72-75.

Abstract(15) PDF(1)

Abstract:
Hard-line steel has higher carbon content,lower sulfur and phosphorus content,so its producing process is quite strict.The off-grade steels often occur because its carbon or phosphorus content was out of grade.On the base of thermodynamics and kinetics analysis of dephosphorization,the main factors of influencing dephosphorization were expounded in this paper.The key point of fast dephosphorization is extending the working time in lower temperature zone and creating the slag of good liquidity,high alkalinity and having a certain degree of oxidizability.So the converting hit rate of carbon,phosphorus and temperature could be obtained.

Practice on the Development and Utilization of Vanadic Titanomagnetite Resources in Panzhihua

Chen Yong

2009, 30(4): 76-80.

Abstract(26) PDF(3)

Abstract:

Surrounding the comprehensive utilization of vanadic titanomagnetite resourses in Panzhihua,the background and course of Pangang's development have been reviewed,and achievements gained by independent innovation in making fully use of the vanadic titanomagnetite resources of Pangang have been summarized.It is pointed out that a promising development of Pangang will be complied with this principle on which Pangang must be dedicated to take complete advantage of unique vanadic titanomagnetite resources and capable of well balancing profits gained from comprehensive resources utilization against production cost increase due to specific resource conditions,process constraints and market situation.Furthermore,it has been emphasized that seeking for further development still highlights comprehensive utilization of vanadic titanomagnetite resources in Panzhihua.

The Strategic Thinking of Forging a World-class Industrial Vanadium-titanium Base in Panxi Area of China

He Wen, Zhao Zehong, He Qing

2009, 30(4): 81-84.

Abstract(17) PDF(1)

Abstract:

The author analyzes the status and comparative advantages of vanadium-titanium industry in Panxi area of China,draws the conclusion that it's necessary and possible to set up a world-level vanadium-titanium industry base there,analyzes further the restrictions and difficulties of the development of the vanadium-titanium industry and proposes measures and countermeasures to solve those problems.

2009 Vol. 30, No. 4