钢铁钒钛

Study on Microstructure and Mechanical Properties of V-N Microalloyed Heavy Section H Beam and Precipitates in the Steels

CHENG Ding, PAN Tao, ZHANG Yongquan, WANG Enrui

2008, 29(3): 1-6.

Abstract(62) PDF(1)

Abstract:
There apt to be different mechanical performance in different positions of high strength heavy section H beam.In this paper the effect of V-N microalloying on section homogeneiey of mechanical properties of H beam is studied.The result shows that V-N microalloying helps to improve section homogeneity of mechanical property for H beam,especially for strength enhancement in conjonction joint of flange and web plate.The above phenomena are closely associated with different precipitation behavior in different positions of H beam.

Study on Characteristics of As-cast Structure of High Strength Steels Microalloyed with Ti by Thin Slab Casting and Direct Rolling Process

SU Liang, MAO Xinping, TIAN Naiyuan, LIN Zhenyuan

2008, 29(3): 7-10.

Abstract(65) PDF(1)

Abstract:
The as-cast structure,chemical composition segregation,dendrite arm spacing and inclusions of the high strength steels microalloyed with Titanium were investigated.The results show that there is no difference between CSP slab and conventional cast slab for macrostructure.However,the macrostructure of slab is relatively finer.The dendrite arm spacing is lower than conventional cast slab too.Segregation for elements C,S,P is large and the others segregation are small in the CSP slab.The big inclusions are few in the CSP slab.The Al,Ti,Ca and S inclusions are main inclusion in the slab,and the Ti,Ca and S inclusions content are few because the element content are few.The size of Al inclusion is lower than 2.5 μm,and equality in the slab.The content of Al inclusion is about around 0.001 4%~0.002 2% and no obviously gathering in the slab.

Effects of Niobium Microalloying on the Microstructure and Properties of Low Carbon Aluminum-killed Steel Sheet

ZHENG Zhiwang

2008, 29(3): 11-16.

Abstract(55) PDF(1)

Abstract:
Effects of microalloying of 0.017% niobium on the microstructure and properties of low carbon aluminum-killed steel sheet were investigated by analyzing its microstructure and properties in as hot-rolled and as annealed conditions as well as its recrystallization behavior during annealing at different coiling temperatures.The results showed that the ferrite grain of the hot-rolling band of the low carbon aluminum-killed steel tends to be nonpolygonal at low coiling temperature.However its properties is little affected by the hot-rolling coiling temperature.The ferrite grain size of the low carbon aluminum-killed steel is finer in as annealed condition than that in as hot-rolled condition,and hence its strength in as annealed condition is greater than that in as hot-rolled condition when the annealing temperature is low.On the other hand,lower coiling temperature would result in higher strength.The ferrite grain of hot band is obviously refined and hence the strength of hot band is significantly increased whereas the recrystallization annealing is prohibited after niobium microalloying.It was also found that the strength of the niobium-treated steel in as annealed condition is almost equal to that in as hot-rolled condition when the annealing temperature is low and tends to be equivalent to that of the low carbon steel annealed at lower temperature when the annealing temperature is high as a result of the coarsening of niobium precipitates and ferrite grains.

Research on Non-metallic Inclusions of Gas Cylinder Steel

GAO Jinguo, LI Jingshe, TANG Haiyan, JIANG Guilian, YAO Jiahua

2008, 29(3): 17-21.

Abstract(93) PDF(2)

Abstract:
Aiming at gas cylinder steel produced by EAF-LF-VD-CC route in a domestic steel mill,the quantity and changes of total oxygen,microinclusions and macroinclusions in the liquid steel at different steps of total process were studied by the way of sampling systematically and comprehensive analysis.The results show that the quantity of microinclusions decreases from 16.7个/mm² to 6.1个/mm² after LF and VD refining.The inclusion is not modified completely during wire feeding.The molten steel has been reoxidized severely in tundish.The total oxygen is(10±2)×10^-6 in round billet,and macroinclusion in it is 0.2 mg/kg.

Study on Pulverized Coal with Mixture Additive Used for Blast Furnace in Laboratory

PENG Qichun, ZHOU Fei, GUO Yibin

2008, 29(3): 22-26.

Abstract(47) PDF(1)

Abstract:
In order to strengthen combustion of pulverized coal and improve combustion capability,the effect of coal combustion capability with different blending ratio of additives has been studied by TG/DSC and orthogonal experiment,which bases on the combustion-supporting mechanism of additives.The result of TG/DSC analysis shows that CaCO₃ can be selected as the main composition in mixture additives as well as MnO₂ and CeO₂.The result of orthogonal experiments of coal powder combustion shows that both burning velocity and combustion ratio of coal have been enhanced greatly.The burning velocity of coal with additives increased by 0.45~0.91 mg/min and the combustion ratio by 20%.Meanwhile,the optimization condition is w_(CaCO₃):w_(MnO₂):w_(CeO₂)=1.5:2.5:2.5,and the CaCO₃ level changing has a remarkable effect on the test results.

Research on Preparation of Vanadium Trioxide by Means of Fluidization

ZHANG Fan

2008, 29(3): 27-30,44.

Abstract(58) PDF(1)

Abstract:
Vanadium trioxide is prepared from reducing APV by means of fluidization.The experimental results showed that TV content of vanadium trioxide product is over 63% when reaction temperature is 700~750 ℃,reaction time is 10~15 min.By comparison with rotary kiln process,the reaction time of this method is shorter and reaction temperature is lower,TV content of the product is higher(>67%) and C content of product is lower,so it is useful to control C content of ferrovanadium.At the same time,the production efficiency of this method is higher,the consume of reductant is lower,the equipment is more secure.

Study on Ion Exchange Membrane as a Separator for All-vanadium Redox Flow Battery

RAN Hongbo

2008, 29(3): 31-34.

Abstract(82) PDF(1)

Abstract:
The physical and electrochemical properties of ion exchange membrane PE-01 and Nafion were studied in all-vanadium redox flow battery(VRB).It was shown that the ion exchange capacity(IEC) and chemical stability of Nafion membrane was better than that of PE-01 membrane.In addition,Nafion membrane with high conductivity was suitable for high charge-discharge current,but it was easier for vanadium solution to permeate through the Nafion membrane than the PE-01 membrane,leading to quicker water transport and relatively lower coulombic efficiency.Then PE-01 membrane has fewer water transport volume and lower VO²⁺ diffusibility than Nafion membrane.

Research on Recovery of Synthetic Rutile Leaching Liquor

WANG Yanhua

2008, 29(3): 35-40.

Abstract(32) PDF(1)

Abstract:
Ruthner acid regeneration device is used to recovery of synthetic rutile mother liquor.Based on a comparative analysis on steel sheet pickling solution and synthetic rutile mother liquor in respects of chemical composition,concentration,density and viscosity,parameters such as hearth temperature,air-coal ratio,spray flow,absorption flow have been optimized The effects of these parameters on Cl^- decomposition rate have been investigated,So the optimal process parameters are ascertained accordingly.Reclaimed acid with a concentration of 218.6 g/L and ferric oxide with TFe≥65% were abtained.Then,an effective solution to comprehensive recovery of synthetic rutile mother liquor has been offered.

Application of Industrial Slag Containing TiO₂ in Fettling Mix for Converter

WANG Huaibin, CANG Daqiang, HAO Jianzhang

2008, 29(3): 41-44.

Abstract(50) PDF(2)

Abstract:
Physical and chemical properties of industrial slag containing TiO₂ is analyzed,and material properties of the fettling mix for converter such as density,strength,high-temperature stability and slag corrosion resistance are studied afrer adding industrial slag containing TiO₂ into fettling mix for converter.The results show that the industrial slag containing TiO₂ has higher strength and better high temperature performance,it doesn't affect the basic properties of refractory and can also raise corrosion resistance of refractory when adding industrial slag containing TiO₂ into fettling mix for converter instead of magnesia.

Numerical Simulation on Level Fluctuation in Mold for Wide Slab Continuous Casting

CHEN Yang, ZHANG Jiongming

2008, 29(3): 45-50.

Abstract(83) PDF(2)

Abstract:
Based on the 150 mm×(1 600~3 250) mm wide slab caster mold as investigating object,the level fluctuation in the mold of the wide slab continuous casting was simulated by a three dimensional finite-volume model(VOF) which had been formulated according to the commercial code ANSYS CFX10.0.The effects of the casting speed、nozzle port angle、strand width on the level fluctuation in the mold had been studied.The simulation results show that with increasing of casting speed or width of strand,the wave height was enhanced.and the larger nozzle port angle,the smaller level fluctuation.

Heat Transfer Analysis for Slag Skull Thickness of Blast Furnace

LIU Zengxun, Lü Qing

2008, 29(3): 51-54.

Abstract(88) PDF(3)

Abstract:
Three dimensional heat transfer model is presented by finite element software ANSYS.Based on element birth and death technology,an iterative routine for slag skull melting is established to determine effect of process condition on slag skull thickness in steady state.The result shows that BF gas temperature has an obvious influence on slag skull thickness.And cooling water velocity has less effect on it.In higher gas temperature condition,the slag skull thickness is remarkably increased by decreasing the gap width.The slag skull thickness is related obviously to the measured temperature and heat load of cooling stave.The heat transfer analysis is optimized by the iterative routine for slag skull melting in this model.The slag skull thickness on BF cooling stave can be calculated by the established model in different conditions.

Control of Transverse Corner Cracks on Continuous Casting Slab for HSLA of Panzhihua Steel

CHEN Yong, YANG Subo, ZHU Miaoyong

2008, 29(3): 55-62.

Abstract(50) PDF(1)

Abstract:
Factors influencing transverse corner cracks in continuous casting slab,such as level fluctuation of molten steel in mold,mold taper,primary cooling,casting powder,secondary cooling,process parameters of CC,etc.,have been analyzed.Based on this,some effective countermeasures have been proposed,such as stabilizing steel level,optimizing the mold taper,weakening the primary cooling and the secondary cooling,reforming the casting powder,and so on.With all these countermeasures,transverse corner cracks on continuous casting slab have been significantly reduced,and the edge cracks on hot rolled sheet have been eliminated due to the transverse corner cracks.

Quality Control of 34Mn2V Non-quenched and Tempered Steel Produced by Continuous Casting Technology

DAI Huayun, WEI Qingfeng, CAI Kesen, KE Xiaotao, LEI Xiuhua

2008, 29(3): 63-67.

Abstract(30) PDF(1)

Abstract:
The quality level of 34Mn2V steel produced by continuous casting was presented.Considering the properties and applications of 34Mn2V steel,the technologies,such as ladle Ar stirring,LF/RH refining,mold electromagnetic agitating,overheating degree control during continuous casting and light reduction,were used,as a result,high cleanliness and good surface quality of 34Mn2V steel were obtained,and [H]≤1.8×10^-6;T[O]≤12.0×10^-6,A type inclusions ≤2.0 grade,B and C type inclusions ≤1.0 grade and D type inclusions ≤1.5 grade.The properties of high pressure seamless gas cylinders after punched were stable,the strength and toughness were relatively high and the requirements of service safety can be met.

Application of the Microwave Heating Technology in the Titanium Metallurgy

CHEN Jin, ZHANG Shimin, PENG Jinhui, CHEN Guo, HUANG Mengyang, LEI Ying

2008, 29(3): 68-72.

Abstract(56) PDF(2)

Abstract:
Based on the brief introduction of the microwave heating mechanism,the results of experiment of microwave heating technology on the titanium metallurgy were summarized and analyzed.The results show that the technology of microwave heating has a promising application prospect in the fields of ilmenite pretreatment,ore milling,carbothermal reduction and liguid-phase extraction of titanium.On the basis of analyzing the existing questions in the process of ilmenite pretreatment by microwave heating technology,we think about that the investigation on the basic theory of the interactions between microwave and minerals and the development of the higher-power industry microwave heating equipments will promote the technology of microwave heating industrialization.

2008 Vol. 29, No. 3