钢铁钒钛

Theoretical Analysis on Use of V-Ti Magnetite in a New Route

Zhang Jun, Yan Dingliu, Qi Yuanhong

2015, 36(3): 1-5. doi: 10.7513/j.issn.1004-7638.2015.03.001

Abstract(60) PDF(2)

Abstract:
The feasibility of resources comprehensive recycling from V-Ti magnetite by sodium alkali reaction and carbothermic reduction in one-step was discussed through thermodynamics analysis. Based on the calculation,rational process route was proposed,and corresponding measurements were put forward to improve the product qualities of vanadium and titanium. The calculation results show that,the treatment of V-Ti magnetite by sodium alkali reaction in range of 850 ~ 1 155 ℃ and deep reduction below 1 400 ℃ is rational. Meanwhile,the addition of sodium salt is favorable for the reduction of iron bearing minerals,and the carbon enhances the sodium reaction. The impurity content in leaching liquid decreases and the quality of V-Ti product is improved greatly via controlling the ratio of aluminum to silicon,and how to realize the separation between vanadium and titanium is the direction of future efforts. When the sodium agent is cycled in the form of NaOH solution and NaHCO₃,the evaporation process is avoided,and the energy consumption can be greatly reduced.

Titanium Concentration of Dry Tailings from Iron Separation of a Low-grade Vanadium-titanium Magnetite

Chen Chao, Zhang Yushu, Zhang Shaoxiang, Long Yunbo

2015, 36(3): 6-10. doi: 10.7513/j.issn.1004-7638.2015.03.002

Abstract(60) PDF(1)

Abstract:
The dry tailings from iron separation of a low-grade vanadium-titanium magnetite contain 9.65% TiO₂. Due to an acute shortage of water in the mining area,titanium resources in the tailings have not been recycled. Considering the dissemination features of iron and titanium minerals in the tailings,a technical solution of dry pre-concentration for discarding followed by grinding and low-intensity magnetic separation for iron removal,then high-intensity magnetic separation and flotation for titanium concentration was designed. The effects of relevant factors (magnetic field intensity,grinding fineness,etc.) on the results were studied. Finally,the obtained titanium concentrate contained 45.29% TiO₂ with a recovery rate of 45.34%,which indicates an effective recovery of titanium resources in the ore.

Research on Reducing Compactness of Titanium Sponge

Wang Cong, Yang Yangjun, Li Kaihua, Gu Lili

2015, 36(3): 11-15. doi: 10.7513/j.issn.1004-7638.2015.03.003

Abstract(54) PDF(1)

Abstract:
The optimal experiments for reducing compactness of titanium sponge were carried out,and the influences of feeding speed,reaction temperature,liquid height and feeding way on the compactness of titanium sponge were studied. The results show that the average barrel rate of titanium sponge can reach to 63.0% and 62.6% by multi-point feeding and reducing the feeding speed,respectively. By reducing the reduction temperature and liquid height by 100 ℃ and 150 mm,the average barrel rate of titanium sponge can reach to 61.3% and 61.2%,respectively. The obtained titanium sponge in the experiments meets the 0 grade of the national standard. It can be seen from SEM images that the products in the experiments have the original layered sponge structure.

Study on Vanadium Precipitation from Solution Containing High Concentration Sodium Vanadate by Hydrolysis

Ying Zhaoqian, Guo Jike, Chen Xiangquan, Fu Zibi

2015, 36(3): 16-20. doi: 10.7513/j.issn.1004-7638.2015.03.004

Abstract(93) PDF(8)

Abstract:
Process of vanadium precipitation by hydrolysis is closely related to the properties of vanadiumcontaining solution such as the content of impurities,concentration of vanadium species,temperature and pH value of the solution. Vanadium pentoxide with purity > 99.5% satisfying the application requirements was obtained by the processes of silicon removal from high concentration sodium vanadate solution,vanadium precipitation by hydrolysis and sodium removal. The optimum process parameters for silicon removal from high concentration sodium vanadate solution are shown as follows: the molar ratio of aluminum sulfate to silicon in the solution is 1.0,the temperature and time for silicon removal is respectively 95 ℃ and 60 min,and the pH value of vanadium solution is 10.0. More than 99.0% of vanadium recovery rate can be obtained by vanadium precipitation with optimum vanadium concentration of 50 g/L,pH value of 2.5 and temperature of 90 ℃.

Kinetics of Photo-catalytic Degradation of Methyl Orange by W,N-TiO₂/SiO₂/Fe₃O₄ Magnetic Photocatalyst

Li Xue, Zhang Yan, Zhang Ying, Jin Ze, Liu Yunyi

2015, 36(3): 21-25. doi: 10.7513/j.issn.1004-7638.2015.03.005

Abstract(51) PDF(1)

Abstract:
W,N-TiO₂/ SiO₂/ Fe₃O₄ magnetic photocatalyst was prepared by low temperature sol-gel method,and its adsorption and catalytic degradation of methyl orange in organic wastewater respectively during the dark reaction and photoreaction was studied. Through degradation of methyl orange with different concentrations by the W,N-TiO₂/ SiO₂/ Fe₃O₄ magnetic photocatalyst,the degradation was confirmed to be a first-order reaction meeting the Langmiur-Hinshelwood (L-H) kinetics model with reaction rate constant k= 2.18 mg/(L·min) and apparent adsorption equilibrium constant K = 0.075 (L/mg). The half-life of reaction was found to lengthen with the increase in the initial concentration of methyl orange.

Influence of Rutile Nano-TiO₂ on Ultraviolet Resistance of Paint

Wu Jianchun, Lu Ruifang

2015, 36(3): 26-29. doi: 10.7513/j.issn.1004-7638.2015.03.006

Abstract(50) PDF(2)

Abstract:
Rutile nano-titanium dioxide was modified by surfactant to improve its dispersion in organic solvents. The modified nano-titanium dioxide was respectively used in furniture paint,anticorrosive paint and automotive paint. The ultraviolet resistance of the paints was achieved by detecting the color difference and gloss loss rate under ultraviolet aging. The results show that the nano-titanium dioxide modified by B/C surfactant has excellent dispersion in the paints. Excellent anti-ultraviolet performance can be obtained in the paints by application of the modified nano-titanium dioxide,and the color and gloss retention properties of the paints are improved enormously.

Study on VC Reinforced Iron Matrix Surface Composite Camshafts Fabricated by Cast-sintering

Ding Yichao

2015, 36(3): 30-34. doi: 10.7513/j.issn.1004-7638.2015.03.007

Abstract(59) PDF(1)

Abstract:
surface composite camshaft was prepared by casting and powder metallurgy,and the microstructure of this surface composite material was analyzed by XRD,SEM and EDS. The results show that the surface composite layer is VC particle reinforced iron matrix composite,and the composite has a good metallurgical bonding with the matrix. The properties of the camshaft surface composite layer were tested,and the results show that the composite material has good wear resistance and high-temperature oxidation resistance.

Effects of Interlayer Annealing Temperature on the Thermochromic Properties of VO₂/TiO₂ Thin Film

Zhang Yubo, Miao Jingguo, Li Zhihong, Huang Wanxia

2015, 36(3): 35-40. doi: 10.7513/j.issn.1004-7638.2015.03.008

Abstract(30) PDF(1)

Abstract:
TiO₂ interlayer was deposited on the mica substrate,and the VO₂ film was fabricated on the TiO₂ interlayer under UV light irradiated. Video-based contact angle measuring device was used to analyze the hydrophilicity of the TiO₂ interlayer. XRD,FTIR and UV-vis were used to analyze the microstructure and the thermochromic properties of the VO₂/ TiO₂ composite films. The results suggest that the hydrophilicity of the TiO₂ film can be enhanced under ultraviolet excitation,and it is beneficial to coat V sol film uniformly on the TiO₂/ mica substrate. The VO₂/ TiO₂ composite films grow in a preferred orientation along the (011) direction under 510 ~ 560 ℃ of TiO₂ interlayer heat treating temperature. The transition temperature and hysteresis width of the composite films are reduced. The composite films grow in a preferred orientation along the (111) direction under 460 ℃ of annealing temperature for the TiO₂ interlayer,with more than 92% of shielding efficiency.

Modification of Extracted Vanadium Tailings at High Temperature

Tang Hongjian, Zhang Li, Sun Zhaohui, Xian Yong, Yu Bin

2015, 36(3): 41-44. doi: 10.7513/j.issn.1004-7638.2015.03.009

Abstract(45) PDF(2)

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By X-ray diffraction (XRD) and scanning electron microscopy (SEM),the process mineralogy of modified and unmodified extracted vanadium tailings,especially the influences of mineralogical characteristics of iron (Fe) and vanadium (V) on the reduction,were studied in this paper. The effects of carbon content,reaction temperature and time on the reduction were systematically investigated.Resultsshow that the metallization rate of Fe reaches to 91.86% under the optimum conditions of 25% carbon content,reaction temperature of 1 150 ℃ and reaction time of 2 h,which lays the foundation for the following smelting separation by arc furnace.

Recycle of Waste Water from Vanadium Precipitation by Ammonium Carbonate

Wang Jun, Sun Zhaohui, Liu Jiayuan, Fu Zibi, Su Yi

2015, 36(3): 45-48,61. doi: 10.7513/j.issn.1004-7638.2015.03.010

Abstract(53) PDF(6)

Abstract:
In view of the present situation that the existing industrial technology for vanadium precipitation is not suitable for the carbonated leachate of vanadium slag with high content of calcium and phosphorus,the process of precipitating vanadium by ammonium carbonate ((NH₄)₂CO₃) was adopted for that leachate. The residue washing water in leaching process was mixed with the washing water for vanadium precipitation,concentrated by evaporation and then mixed with the upper-liquor of precipitating vanadium for the reuse as leaching agent. The results show that after 5 times of recycling every component of the obtained product meets the industry standard with more than 99% vanadium pentoxide (V₂O₅). It realized the recycle of waste water.

Improvement of Vanadium Extraction from Extracted Vanadium Residue in China

Meng Lipeng, Zhao Chu, Wang Shaona, Du Hao, Zheng Shili, Zou Xing

2015, 36(3): 49-56. doi: 10.7513/j.issn.1004-7638.2015.03.011

Abstract(50) PDF(4)

Abstract:
The composition,phase and morphology of vanadium-bearing tailings from Pan Steel and Cheng Steel were studied in this paper. Combining with the previous studies by others,the valences and possible phases of vanadium in the residue were obtained. By the induction of the research progress of extracting vanadium from low and high valence vanadium tailings respectively from Panzhihua and Chengde,it is concluded that the key issues of extracting vanadium from vanadium tailings are the selective strengthening of the three controlled steps: the decomposition of outer silicate mineral,the structure destruction of residual vanadium iron spinel and the oxidation of low valence vanadium in the tailings. Thus,it is proposed that different extracting methods should be employed according to the characteristics of the specific tailings.

Mineralogical Characteristics of Sulfide in Hongge Vanadium Titano-magnetite

Luo Jinhua, Wu Zhaoyu, Li Junhan, Wu Eenhui, Liao Xianjie, Tang Rui, Yang Shaoli

2015, 36(3): 57-61. doi: 10.7513/j.issn.1004-7638.2015.03.012

Abstract(34) PDF(2)

Abstract:
In this paper mineralogical characteristics of sulfide in vanadium titano-magnetite of Panzhihua Hongge area,Sichuan province had been extensively investigated by the methods of optical microscope,SEM,EMPA,XRF etc. The observation results reveal that metal (Co,Ni,Cu,Fe,etc) sulfide-based pyrrhotite and pyrite present in the ores and distribute in titanium-ferro oxides and silicate minerals in form of irregular granula or aggregates. The content of Co,Ni,Cu and Fe,S are not significantly related with each other. Sulfide is composed of various contents of pyrrhotite,pyrite and chalcopyrite. The results will help to the comprehensive utilizations of the sulfide in this kind of ore.

Air Humidification Performance of the Sintered Test

He Mugang, Jiang Dajun, Song Jian, Yi Kai, He Xuan, Guo Gang

2015, 36(3): 62-66. doi: 10.7513/j.issn.1004-7638.2015.03.013

Abstract(51) PDF(1)

Abstract:
In order to explore the effect of air humidification on sintering performance of vanadium-titanium magnetite concentrate,sinter layer surface air humidification test had been carried out in the laboratory. From the experimental results it is found out thatspraying 0.4% water after 18 minutes of the ignition,generated the maximum yield where utilization coefficient is 1.31 t/(m²·h) and yield increases by 15.94% compared with the benchmark; At the same time the second best yield has been achieved when secondary ignition sintering is completed without water spray,consequently utilization coefficient is 1.281 t/(m²·h) and yield increases by 13.40%. On the other hand,when a composite index is used for evaluation,the best result comes from the 0.4% water spray after 18 minutes ignition with composite index of 98.54,followed by implementation of second ignition sintering (not spray) with composite index of 98.50,and the worst case is 0.3% water spray after 18 minutes ignition with its composite index of 97.33.Nevertheless,all three processes can produce higher composite index than the baseline of 96.25.

Mineralogical Structure of Vanadium-titanium Sinter Produced by Acid Pellets and Alkaline Materials Mixed Sintering

Ding Haichao, Li Fumin, Sun Yanqin, Cheng Shujun, Lü Qin, Huang Honghu

2015, 36(3): 67-72. doi: 10.7513/j.issn.1004-7638.2015.03.014

Abstract(51) PDF(1)

Abstract:
Vanadium-titanium sinter produced by acid pellets and alkaline materials mixed sintering of thick material layer is a new sintering process where high alkalinity and acidity ball are made from the upcoming vanadium-titanium iron concentrate powder and then mixed with fuel and returned ore for further sintering. The experimental results showed that,compared with conventional sintering process,addition of acidic pellets had changed sintered material layer structure which led to the better breathability,improved sinter yield and increasing contents of calcium ferrite and magnetite while reducing hematite and perovskite contents. As a result,the strength and RDI of sinter have been improved.

Effect of MgO Content on the Quality of Low-titanium Sinter

Liu Ran, Li Hongwei, Li Haojie, Li Yanjiang, Liu Song

2015, 36(3): 73-77. doi: 10.7513/j.issn.1004-7638.2015.03.015

Abstract(28) PDF(1)

Abstract:
In this paper the effects of different Mg O content on resulting sinter quality were investigated. The results show that with Mg O content increasing,sinter indexes are affected to different degrees. Appropriate Mg O content benefits to the yield,drum strength and the metallurgical properties of sinter. Considering the relationship among Mg O and parameters in the sintering process,the composition,yield,drum strength and the metallurgical properties of sinter,the optimum Mg O content should be at 2.50% to 3.00%.

Phase Analysis and Phosphorus Transformation in Sintering Gasification Dephosphorization Process

Zhang Wei, Wang Hui, Xing Hongwei, Tian Tielei, Wu Lizhong, Liu Fan

2015, 36(3): 78-82. doi: 10.7513/j.issn.1004-7638.2015.03.016

Abstract(38) PDF(2)

Abstract:

In order to explore the transformation mechanism of phosphorus during sintering process,minisintering experiment was carried out based on the thermodynamic calculation,and the component and phase of calcined product were analyzed. The results show that the dephosphorization ratio reached up to 20% in the conditions of 4% carbon,1.41% SiO₂ and 1.36% CaCl₂; When adding SiO₂,Ca₅(PO₄)₃F is transformed into Ca₃(PO₄)₂ through defluorination reaction,and then dephosphorization reaction takes place. After adding CaCl₂,the diffraction peak of Ca₅(PO₄)₃F decreases,while diffraction peak of CaSO₄ enhance obviously,at the same time both CaF₂ phase and CaSiO₄ phase appeare,which indicating the occurrence of gasification dephosphorization reaction with PCl₃ as dephosphorization product.

Effect of Slag and Hot Metal Compositions on Arsenic Content in Molten Iron

Lü Qing, Huang Honghu, Liu Xiaojie, Qie Yana, Ding Haichao

2015, 36(3): 83-87. doi: 10.7513/j.issn.1004-7638.2015.03.017

Abstract(47) PDF(2)

Abstract:
The impact of slag basicity,initial sulfur content and temperature of hot metal on the arsenic content in hot metal were studied in this paper.Results show that arsenic content increases with basicity (% CaO)/(% SiO₂). When basicity exceeds 1.16 arsenic content changes slowly. Increasing slag basicity at a certain level is in favor of dearsenication. As the initial sulfur content in pig iron increases,arsenic content in hot metal increases,which indicating that slag dearsenication rate decreases. Thus,higher sulfur content in pig iron results into a higher arsenic level in hot metal. In the practical production [S]should be minimized and sulfur content in pig iron should be controlled in order to lower arsenic content. Dearsenication rate decreases with increasing temperature in the range of 1 400 ~ 1 550 ℃.When temperature exceeds 1 475 ℃,the dearsenication rate decrease drastically.

Study on Cleanliness of Q235B Steel under the Conditions of Substituting Iron Ore for Partial Scarp in Converter

Wang Jiajie, Peng Qichun, Zhou Mingwei, Peng Mingyao, Bi Jianmin

2015, 36(3): 88-92. doi: 10.7513/j.issn.1004-7638.2015.03.018

Abstract(27) PDF(1)

Abstract:
Oxygen and nitrogen analyzer,metallographic examination,SLIME,SEM and EDS techniques had been used to study the cleanliness of plain carbon structural steel Q235B produced via KR-BOF-ArCC process under the conditions of substituting iron ore for partial scarp in converter. The results show that the total amount of microscopic inclusions decreases from argon refining inlet to casting process. After argon refining,average number of microscopic inclusions decreases by 26.63%,indicating a significant effect from argon refining. Major microscopic inclusions at various steps are Al₂O₃ and Mn S as well as small amount of CaO-MgO-Al₂O₃,CaO-Al₂O₃ and MgO-Al₂O₃ composite inclusions. In the process of argon refining,TO content decreases by 19.60×10^-6 while casting step makes TO content increase by 10.55 × 10^-6 which is due to molten steel secondary oxidation or slag entrapment. From the converter to the casting process,the average nitrogen content gradually increases and maximum nitrogen increasing takes place during the convertor to argon refining process. The large inclusions are dominant SiO₂ and small amount of MgO-Al₂O₃-SiO₂.

Hydraulics Simulated Experimental Study on a Two Strand Tundish at Different Flow Rate

Liu Hui, Wang Jia, Liang Jian, Zhou Li

2015, 36(3): 93-98. doi: 10.7513/j.issn.1004-7638.2015.03.019

Abstract(49) PDF(1)

Abstract:
A 1∶2.5 hydraulics modle experiments were conducted to simulate a 72 t two- strand slab continuous casting tundish. The impact of using flow control devices and turbulence inhibitor on the flow field in tundish at different flow rate of flow had been investigated in order to gain the best combination of flow control devices in the inner cavity. The result shows that the best combination of flow control device includes 80 mm depth of weir,100 mm,height of dam,80 mm distance between weir and dam,as well as installation of turbulence inhibitor. When the flow flux are 1.63,2.00,2.57 and 3.00 (m³/ h),the shortest residence time increase by 13,7,22 and 13 seconds,and dead area ratio decreases by 3.5%,11.2%,9.1% and 13.8%,respectively.

Bubbles Separation Behaviour of Cr12N Steel during High Pressure Solidification Process

Wang Shuhuan, Liu Jimeng, Zhao Dingguo, Huang Kai, Li Weifeng

2015, 36(3): 99-103. doi: 10.7513/j.issn.1004-7638.2015.03.020

Abstract(39) PDF(2)

Abstract:
Considering the some bubbles separation during smelting Cr12N ferritic stainless steel,the ingot had been examined by an optical microscope,and the optical image had been analysed by using a microimage analysis & process software. It is found out that when the melting pressure is 0.6 MPa and solidification pressure is increased from 1.0 MPa to 1.6 MPa,the average number of bubbles per square millimeter decreases from 46.37 to 9.46,among them the number of bubble with diameter greater than 20 μm reduces down to 17.4% of origin number,while the number of bubble with diameter less than 5 μm increases by 37.7%. With increasing solidification pressure,the bubble area percentage becomes smaller. When the ingot is produced at a combined conditions of 0.3 MPa melting pressure and 1.6 MPa solidification pressure,the average bubble area percentage on lower surface is 23.9% of that on the upper surface,and average bubble area percentage at the edge position is 25.9% of that at the center position.

HAZ Toughness in Vanadium-microalloyed Steels

Fahlström K, Hutchinson B, Komenda J, Lindh-Ulmgren E, Martin D, Beladi H

2015, 36(3): 104-110. doi: 10.7513/j.issn.1004-7638.2015.03.021

Abstract(31) PDF(1)

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The present paper refers to the situation of single-pass welds in structural steels and,in particular,the mechanical properties and microstructures of the coarse grained heat affected zones (CGHAZs) that exist in the parent material close to the fusion line. Frequently,the toughness in these areas is lower than that of either the base steel or the weld metal and so they may represent the weakest link in the structure with respect to fracture. We concentrate on the characteristics of a vanadium-microalloyed plate but a similar strength niobium steel is included as a relevant comparison. To best utilize the strengthening effect of vanadium in steel it is necessary to enhance the nitrogen level to typically 0.01% and it is the combination of V and N that must be considered when attempting to rationalize the properties of the steels.

Effects of RH Refining Deoxidation Method on the Non-metallic Inclusions in Non-oriented Si Steel Sheets Containing Al

Lü Xuejun, Zhang Feng, Chen Xiao

2015, 36(3): 111-115. doi: 10.7513/j.issn.1004-7638.2015.03.022

Abstract(57) PDF(4)

Abstract:
The oxygen element is harmful to Si steel,and the RH refining deoxidation method has an important effects on oxygen concentration. Based on the industrial non-oriented Si steel containing Al,the effects of RH refining deoxidation method on non-metallic inclusions was investigated. The results show that the oxygen concentration in liquid steel from Si-Al deoxidation sequence method is higher that of AlSi deoxidation sequence method. The average yield of Si and Al for Si-Al deoxidation sequence method are 90.7% and 78.2%,respectively,and those for Al-Si deoxidation sequence method are 97.5% and 63.7%,respectively. The Si-Al deoxidation method is superior to the Al-Si deoxidation method in terms of Si and Al yields. Thus,from the viewpoint of controlling magnetic properties,Si-Al deoxidation sequence method is recommended. The major non-metallic inclusion is composite of MnS and Cu_xS generating from Si-Al deoxidation sequence,and individual Al N and complex Mn S and Al N inclusions dominate in Al-Si deoxidation sequence. Average inclusion sizes are 0.73 μm from Si-Al deoxidation sequence and 0.38 μm from Al-Si deoxidation sequence.

Study on Structure and Property of High Grade Non-Oriented Silicon Steel Sheet via 20 mm Thin Slab

Xue Yanchun, Ma Liang, Qiu Shengtao

2015, 36(3): 116-121. doi: 10.7513/j.issn.1004-7638.2015.03.023

Abstract(38) PDF(1)

Abstract:
2.9%Si-0.77%Al non-oriented silicon steel slab had been produced by the thin slab process with a thickness of 20 mm. After hot rolling,normalizing,cold rolling and annealing,the resulting sheet had been investigated in terms of microstructure,precipitates and magnetic properties. The results show that thin casting slab has a typical transcrystalline grain structure,while the structure of hot rolled strip comprising of fine recrystallized grain at edge and coarse deformed structure in the center. Normalizing process leads to a fully-recrystallized microstructure,and finished sheet is characterized by an equaixed grain microstructure. The precipitates are dominant coarse AlN and (MnS+AlN) composite in size of 0.5~ 2.5 μm. The magnetic property of resulting silicon steel are P₁₅= 2.86 W/kg and B₅₀= 1.70 T.

Cause Analysis of Cracking for frame tube

Li Yanjie, Song Jinying, He Lixin, Gao Ying

2015, 36(3): 122-126. doi: 10.7513/j.issn.1004-7638.2015.03.024

Abstract(35) PDF(2)

Abstract:
Narrow strip steel was used to make the frame tubes. The crack occurred to Q195 when frame tubes were formed. The cause of frame tube cracking is studied by the means of scanning electron microscope,OM,EDS. The result shows that the reason of frame tube crack is Fluxes involved,silicate inclusions Excessive,welds tissue overheating and the degree of cold work hardening is high. It aimed at the crack of different way to research and put forward some measures to improve. Many rectification measures like optimizing the steelmaking process,cooling process after rolling and the welding process were proposed according to the researches on various crack modes. Finally,the crack defect frame tube was effectively controlled. The crack defect rate was reduced from initial 25.5% to 2.7%,which led to the improvement of the yield.

Effect of Submicron-CeO₂ Particles on the Microstructure and Performance of Low Carbon Steel

Peng Jun, Niu Liang, Wang Jian, An Lei, Guo Yong, An Shengli

2015, 36(3): 127-130. doi: 10.7513/j.issn.1004-7638.2015.03.025

Abstract(32) PDF(2)

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Microstructure refinement is an important means to improve the performance of the steel and oxides metallurgy is an important method of refining microstructures. In this paper SEM observation and hardness measurement had been made on the as-cast and as-rolled steel with submicron-CeO₂ particle addition during steelmaking. SEM observation results show that the addition of CeO₂ submicron powders can refine microstructure of low carbon steel. Addition of CeO₂ leads to average grain size of cast decreasing from 120 μm to 30 μm,while the pearlite quantity increase and pearlite interlamellar spacing reduce from 0.57 μm to 0.11 μm. Increasing the quantity of CeO₂ powder,the hardness of Q235 steel increases. When the CeO₂ content is 0.7%,the resulting hardness increases by 133.4%.

2015, 36(3): 131-132.

Abstract(42) PDF(1)

Abstract:

2015 Vol. 36, No. 3