钢铁钒钛

Commercial Tests for Fluidized-bed Chlorination of Titanium Slag High in Calcium and Magnesium Without Sieve Plate

Wang Jun, Li Liang, Fan Xingping, Zhong Xinaoting

2013, 34(4): 1-6. doi: 10.7513/j.issn.1004-7638.2013.04.001

Abstract(33) PDF(2)

Abstract:
Commercial tests for fluidized-bed chlorination without sieve plate were carried out using titanium slag high or low in calcium and magnesium as main raw materials.In view of the fact that high calcium and magnesium content tends to cause agglomeration of the burden and blockage of the sieve plate which affects the normal process of chlorination,measures including gradual increase of blending ratio of high calcium and magnesium content titanium slag,appropriate addition of carbon and regular deslagging were taken to avoid negative influences.During the experiments,reaction temperatures in the fluidized-bed chlorinator,pressure fluctuation and deslagging conditions,as well as chemical analyses on furnace slag,slag from dust collecting and tail gas were studied.The commercial tests show that as the amount of titanium slag high in calcium and magnesium increases,there is a downward trend for reaction temperature in the fluidized-bed chlorinator and furnace top temperature,which can be solved by additional heat supply; slag discharging and fluctuation of bed pressure as well as the chemical compositions of furnace slag,slag from dust collecting and tail gas are in normal.It is feasible to use fluidized-bed chlorinator without sieve plate to chloridize titanium slag high in calcium and magnesium to obtain titanium tetrachloride.

Feasibility Study on Vanadium Precipitation with(NH₄)₂SO₄-Na₂SO₄ Mixed Salt

Wan Longfei

2013, 34(4): 7-12. doi: 10.7513/j.issn.1004-7638.2013.04.002

Abstract(38) PDF(1)

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In this paper,the feasibility of vanadium precipitation with(NH₄)₂SO₄-Na₂SO₄ mixed salt is studied.The results indicate that vanadium precipitation ratio is at 98.9%~99.3% as the mass ratio of(NH₄)₂SO₄to Na₂SO₄ ≤ 0.3.With TV percentage of 49.85%~50.43%,Na₂O of 0.11%~0.51%,S of 0.100%~0.448%,and K₂O of 0.11%~0.12% after washing of precipitate(APV),it can be found out that Na₂SO₄ content in the mixed salt has little influence on the precipitating process and precipitate compositions.Through precipitate analyzing by SEM and EDS,it can be assumed that Na⁺ and SO₄^2- may exist on the surface of precipitates in a way of surface adsorption,and K+may exist in the precipitate as crystal nucleus or crystal structural ion.The result of the experiment for vanadium precipitation with(NH₄)₂SO₄-Na₂SO₄ mixed salt prepared by concentration of residual liquid of crystallization show that after washing,the precipitate can meet the production requirements.

Preparation of Bio-film on the Surface of Titanium Alloy by Micro-arc Oxidation and Hydro-thermal Synthesis and Its Histocompatibility

Luo Rui, Liu Zhongde, Zhou Xinghua, Cheng Xiaonong, Zhang Yingtao, Wu Wenyu

2013, 34(4): 13-18. doi: 10.7513/j.issn.1004-7638.2013.04.003

Abstract(21) PDF(1)

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Micro-arc oxidation(MAO) and hydrothermal synthesis(HS) technologies were used to prepare bio-film on the surface of titanium alloy.Surface morphologies and formation procedures of the films at various stages were observed by scanning electron microscope,and element and phase compositions of biological membrane layer were analyzed by energy dispersive spectroscopy and X-ray diffractometer.The cohesion between films and substrate materials was measured by scratching test,and the corrosion resistance of samples in Hank's simulated body fluid was probed into.MAO-HS samples and titanium alloy substrate samples were implanted into animal subcutaneous tissue after washing and sterilization.After 52 days of implanting,the samples were taken out and observed.The experimental results show that the cohesion between the films and substrates has a higher binding force of up to 26 N or so,and the corrosion resistance of MAO-HS samples is better than titanium alloy substrate specimen.Large tissues clamber over the surface of MAO-HS group,and the membrane layer contains a certain proportion of carbon and kalium element while there is no tissue growth found on the surface of titanium alloy substrates.Compared with the titanium alloy substrate material,MAO-HS samples shows more excellent histocompatibility as implants.

Studies on Mineralogical Characteristics of Ilmenite in Hongge Vanadium-bearing Titaniferous Magnetite

Luo Jinhua, Qiu Kehui, Zhang Peicong, Qiu Yuchong, Li Junhan

2013, 34(4): 19-24. doi: 10.7513/j.issn.1004-7638.2013.04.004

Abstract(29) PDF(3)

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Mineralogical characteristics including structures,chemical compositions and changing patterns of ilmenite in Hongge vanadium-bearing titaniferous magnetite in Panzhihua,Sichuan,were detailedly studied by optical microscope,scanning electron microscope(SEM),electron probe micro-analysis(EPMA),X-ray diffraction(XRD),X-ray fluorescence(XRF) and differential thermal analysis-thermogravimetry(DTA-TG).The results indicate that ilmenite in Hongge vanadium-bearing titaniferous magnetite exists in independent mineral particle or ilmenite crystal plate or strip exsolved from solid solution of titaniferous magnetite.The ilmenite in the forms of euhedral-subhedral and anhedral crystal particles and titaniferous magnetite form poikilitic structure or filled in gangue grains to form sideronitic texture or web ring texture.The two types of ilmenite observed by mineral phase analysis were oikocryst and chadacryst.The major chemical compositions of the ilmenite are ferrum(Fe),titanium(Ti),magnesium(Mg),vanadium(V) and manganese(Mn).The correlation analysis indicates that Fe,Ti,Mg,V,and Al are closely related to each other.With the decrease of the ilmenite's particle size,ferrum(Fe) content gradually increases while TiO₂ and MgO contents decrease.The results provide significant practical references to ore dressing and separation of the ilmenite in vanadium-bearing titaniferous magnetite in that area.

Producing Refractory Raw Materials with Vanadium Iron Slag

Wang Changmin

2013, 34(4): 25-29. doi: 10.7513/j.issn.1004-7638.2013.04.005

Abstract(33) PDF(1)

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Using vanadium iron slag and magnesite as main raw material,appling co-grinding,machine press forming,high temperature firing processes,a kind of synthetic refractory raw materials can be produced,which has main phases of corundum and spinel,and it's density greater than 3.0 g/cm³,the rate of water absorption less than 1.5%,and refractoriness more than 1 790℃.It can be used in unfired bricks,castable and other products instead of bauxite and firing spinel and other refractory raw materials.In this process,vanadium iron slag can be used as secondary resource and can realize high value utilization.

Numerical Simulation of Flow Fields for Gas Quenching of Steel Slag

Long Yue, Cai Zhenlei, Zhang Yuzhu, Xing Hongwei

2013, 34(4): 30-35. doi: 10.7513/j.issn.1004-7638.2013.04.006

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Mathematical and physical models of granulating process were established to elaborate the granulating mechanism of the gas quenching process of liquid steel slag,and flow fields of granulation process under different conditions were calculated through the FLUENT software.The simulation results show that N₂ jet flow can be divided into three phases,namely the initial phase,fundamental phase,and dissipation phase.The maximum velocity distributes on the axis of the jet flow,and the velocity is inversely proportional to radial distance.The impact kinetic energy and the flow field distribution of the N₂ jet flow have a significant influence on the effect of granulation.The ideal diameter of the Laval nozzle is 10 mm.The increase of mach number is helpful to enhance the impact kinetic energy of the jet flow,and thus contributes to the steel slag granulation.

Experimental Study on Dezincification of BF Dust and Converter Sludge by Reduction

Ju Jiantao, Dang Yaojun, Zhao Zhongyu

2013, 34(4): 36-40,46. doi: 10.7513/j.issn.1004-7638.2013.04.007

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Physico-chemical properties including chemical composition,particle size distribution and phase of BF dust,dust collected by bag-type collector and converter sludge were analyzed.The feasibility for dezincification by reduction was validated by thermodynamic software Factsage and the initial temperature for the reduction was obtained by TG-DSC experiment.Furthermore,the effect of reduction atmosphere,temperature,time and C/O ratio on the metallization and dezincification rate of the above-mentioned dusts and sludge were investigated.Results show that dust pellets can be reduced in weak oxidization atmosphere,and the dezincification rate and metallization rate of the dust pellets increase with the increase of temperature and time.With C/O ratio of 1.1,reduction temperature of 1 300℃ and reduction time of 40 min,metallization rate and dezincification rate of the pellets are higher than 85% and 95% respectively after the reduction.

Reduction Behavior of Ti in Low TiO₂ Content Slag During Blast Furnace Ironmaking Process

Wei Mengfang, Zhang Jianliang, Mao Rui, Liu Zhengjian, Zhao Yongbin

2013, 34(4): 41-46. doi: 10.7513/j.issn.1004-7638.2013.04.008

Abstract(32) PDF(1)

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To determine the appropriate parameters for hearth lining protection by using TiO₂ containing materials,the influence of TiO₂ content in slag,temperature,reaction time,ratio of slag to hot metal,and w_(CaO)/w_(SiO₂)slag binary basicity on reduction behavior of Ti in slag with low TiO₂ content,i.e.,1.0~5.0%,has been experimentally investigated through slag-hot metal reaction.The results show that the increase of TiO₂ content and binary basicity of slag,temperature,and reaction time contributes to Ti content increasing in hot metal.When the reaction time is fixed,TiO₂ content and temperature of slag have noticeable influence on Ti content in hot metal while binary basicity of slag has little influence.When the temperature is fixed,the relationship between Ti content and reaction time can be described by w_[Ti]=kt + c with k and c as constants.Ti content in hot metal increases rapidly with the increase of ratio of slag to hot metal(RSM) from 0.25 to 0.40,and it increases slowly in the RSM range of 0.40 to 0.50;further increase of RSM from 0.50 to 0.80 can result in a slow decrease of Ti content in hot metal.

Progress on Sintering Technologies for Titanium-rich Vanadium-bearing Titaniferous Magnetite

He Muguang, Jiang Dajun, Du Sihong, Song Jian

2013, 34(4): 47-51. doi: 10.7513/j.issn.1004-7638.2013.04.009

Abstract(31) PDF(1)

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Mineral compositions of Panzhihua vanadium-bearing titaniferous magnetite are complex,and its concentrate was low in iron grade and high in TiO₂ content.With the application of staged grinding and staged separation process,the iron grade in the concentrate reached 54%,but TiO₂ content in it was still up to around 13%.Featured by ‘low iron and silica,and high titanium,aluminum,ferrous,and sulfur content’,the concentrate was greatly affected by its coarse particle size as well as poor pelletizing performance in air permeability during sintering.In addition,high initial melting point of the concentrate,a small amount of liquid phase produced from the concentrate,and complex mineral composition of sinter lay significant influence on strength and metallurgical properties of sinter.Over the past decade,through using lime to improve the sinter basicity,separately adding fuel,adding ordinary mineral powder,upgrading sintering machine technologies,and introducing a series of strengthening technologies including high negative pressure and large air flow sintering,significant technological breakthroughs have been made to improve the sintering performances of vanadium-bearing titaniferous magnetite concentrate with sintering machines' utilization coefficient of 1.4 t/(m²·h) and the drum index of 72% or more.The progress on sintering technologies for titanium-rich vanadium-bearing titaniferous magnetite can meet the requirements for sinter.

Research on the Axial Flow of Liquid Metal Driven by a Helical Magnetic Field

Wang Songwei, Na Xianzhao, Zhang Xinde

2013, 34(4): 52-56. doi: 10.7513/j.issn.1004-7638.2013.04.010

Abstract(6) PDF(1)

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Vertical flow of liquid metal in cylindrical and hexahedral vessels driven by a helical magnetic field was investigated in the experiments.The helical magnetic field was constructed with several pieces of permanent magnets magnetizing in the radius direction.The vertical velocity distribution of liquid GaInSn alloy was measured with ultrasonic Doppler velocimeter(UDV).The axial flow resulted from the competition of the large vertical vortex driven by traveling magnetic field and the secondary flow driven by the rotating magnetic field.The axial stirring effect greatly decreased when the secondary flow occurred.

Research on Inclusion Behavior in Continuously Cast Billet for Carbon Structural Steel 40Mn

Zhang Caijun, Dong Jianjun, Sun Xueyu, Wu Hao, Zhu Liguang

2013, 34(4): 57-61. doi: 10.7513/j.issn.1004-7638.2013.04.011

Abstract(16) PDF(1)

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In view of the converter-argon blowing-continuous casting process for production of carbon structural steel 40Mn,oxygen and nitrogen contents and compositions,amounts and variation of microscopic and macroscopic inclusions in casting blanks were systematically analyzed.The results show that the average contents of oxygen and nitrogen in steadily cast billet are about 65 × 10^-6 and 70 × 10^-6; microscopic inclusions are mainly MnS and aluminosilicate inclusions,and the inclusions in unsteadily cast billet is two times of those in normal blank; major macroscopic inclusion is SiO₂ inclusion,followed by SiO₂-Al₂O₃ and SiO₂-Al₂O₃-MnO inclusions,unsteady casting influences steel cleanliness,unsteady control should be strengthened during casting process.

Inclusions Distribution in IF Steel Slabs

Wang Quan, Liu Jianhua, Liu Jianfei, Chen Junjie

2013, 34(4): 62-67. doi: 10.7513/j.issn.1004-7638.2013.04.012

Abstract(23) PDF(1)

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The size,number and morphology of inclusions in IF steel produced by BOF-RH-CC process were analyzed by scanning electronic microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),and metal original position analysis(OPA).The results show that inclusions distribute uniformly along the width direction; the number of inclusions in head slab is much larger than those in other slabs;there is an inclusion accumulation zone around 20 mm away from the inner arc surface where the inclusion content is much higher than those in other positions.The sizes of the inclusions are mainly in 0~5 μm and there is a small amount of inclusions larger than 10 μm gathering in the areas around 20 mm away from the inner arc surfaces of slabs.

Mineral Compositions and Microstructures of AOD Stainless Steel Slag

Wang Yajun, Li Junguo, Zheng Na

2013, 34(4): 68-72. doi: 10.7513/j.issn.1004-7638.2013.04.013

Abstract(12) PDF(1)

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Mineral compositions,microscopic morphology and distribution characteristics of AOD stainless steel slag were analyzed by X-ray diffraction,electron microscope and specialized optical microscope respectively.It is suggested that dominant phases in the slag include C₂S,C₃MS₂,augite,and rankinite,and a small amount of spinel,magnetite and little wustite,glass phase,RO phase and calcium ferrite.The volume fraction of C₂S in AOD slag accounts for above 80%,while that of C₃MS₂,augite or rankinite for about 5% each.C₂S and rankinite are black phases under metallurgical microscope.C₂S exists in fine granular aggregation or column with different particle size,and rankinite mainly in anhedron or fine column.C₃MS₂ is found in gray phase,and mainly in anhedron,fine spindle or short column.Augite,spinel and RO are parceled in advantageous phase,and augite is in anhedron with different particle size.

Influence of Solution Temperature on Structures and Properties of Low-nickel Duplex Stainless Steel 2101

Tang Ruirui, Gong Lihua

2013, 34(4): 73-77. doi: 10.7513/j.issn.1004-7638.2013.04.014

Abstract(16) PDF(2)

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Solution treatments of duplex stainless steel 2101 were performed at 950℃,1 000℃,1 050℃ and 1 100℃ for 30 min respectively.The microstructure variation of the steel at different solution temperature was analyzed by XRD and quantitative metallography,and the hardness and corrosion-resistant properties of the steel were studied by the means of Vickers hardness meter,electrochemical test and slow-strain-rate stress corrosion test.The results show that duplex stainless steel 2101 exhibits excellent phase balance without obvious precipitated phase at the treatment temperature of 950~1 100℃,and the steel treated at 1 050℃ for 30 min has better comprehensive properties.

Development of High-strength Non-oriented Electrical Steel by TSCR

Pan Zhendong, Xiang Li, Zhang Chen, Qiu Shengtao, Wang Zhongying

2013, 34(4): 78-83. doi: 10.7513/j.issn.1004-7638.2013.04.015

Abstract(13) PDF(3)

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TSCR was simulated to develop high-strength non-oriented electrical steel with 3% of Si,0.83% of Al and 2.99% of Mn by solution strengthening,grain refinement strengthening and dislocation strengthening.The microstructures of hot rolled plates,normalized plates and annealed plates were analyzed.Furthermore,the mechanical properties and magnetic properties of products with different microstructures were detailedly studied.As the average grain diameter of the steel was 12.37 μm,the yield strength and the tensile strength of the steel were 530 MPa and 618 MPa respectively.As the annealing schedule of 700℃ × 4 min was applied and the microstructure of the product was totally unrecrystallized,the yield strength and the tensile strength of the steel were 853.5 MPa and 895.5 MPa respectively.As P_15/50 or P_10/400 of the steel was at the minimum value,the corresponding average grain diameter was larger than 60 μm; as P_10/800 or P_10/1000 was at the minimum value,the corresponding average grain diameter was between 12.37 μm and 59.67 μm.

Study on Eco-friendly Insulating Fluid for Non-oriented Electrical Steel Sheet

Dong Xueqiang, Guo Taixiong

2013, 34(4): 84-88. doi: 10.7513/j.issn.1004-7638.2013.04.016

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At present,most of the insulating fluid for non-oriented electrical steel contains chromium,and should be cured at high temperature.On the basis of analyzing the characteristics of the film-forming substance,a kind of eco-friendly insulating fluid with lower curing temperature for non-oriented electrical steel sheet was developed in the experiments.Then its coating process was studied,and the adhesiveness,insulativity,heat resistance,corrosion resistance and other properties of the coating was measured.The results show that the fluid can be rapidly dried and cured at 150℃ to 250℃,and the resulted smooth,compact and uniform coating with excellent performance can meet the application requirement of small and medium-sized motors.

Analysis on the Formation of Surface Crack on Casting Bloom of Hypo-peritectic Steel Q345B

Ai Xi, Sun Yanhui, Zeng Yanan, Ma Zhifei, Liu Ruining, Liu Yong

2013, 34(4): 89-93. doi: 10.7513/j.issn.1004-7638.2013.04.017

Abstract(13) PDF(1)

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Large amounts of surface cracks were found on the 300 mm × 360 mm continuous casting blooms for hypo-peritectic steel produced by EAF + LF + VD processes after cooling.The cracks were analyzed by optical microscopy,SEM and EDS,and thermo dynamical calculation was carried out at the same time in order to find out the reasons for formation of the cracks.The results indicate that decarburized layer and ferrite film are found near the cracks and enrichment of P and S found at the cracks; inclusions containing elements of Al,Mg,Ca and Si wreck continuity of the steel base; mold flux and precipitates have significant effects on surface quality of the casting bloom.In order to protect casting bloom from crack forming,it is necessary to control the superheat of steel between 15 and 30℃,maintain the liquid powder layer between 8.5 and 9 mm,and increase the crystallization rate of mold powder.Keeping the N content of the steel at 35 × 10^-6 to 45 × 10^-6 and increasing the Ti treatment effeciency to decrease the amount of AlN in bloom also contributes to improve the quality of the casting bloom.

Formation and Control of Transverse Corner Cracks in Boron Steel Slab

Liu Guoliang, Ji Chenxi, Ni Youjin, Hu Weidong, Zhang Yinghua, Bao Chunlin

2013, 34(4): 94-98,103. doi: 10.7513/j.issn.1004-7638.2013.04.018

Abstract(13) PDF(2)

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Transverse corner cracks in boron steel were studied through TEM,SEM and optical microscope analyses,and the formation reasons of the cracks were analyzed.The results indicates that BN and AlN precipitate around austenitic grain boundaries due to undercooling at the corner,which aggravates the cracks during continuous casting.Tiny cracks firstly appear along vibration marks at higher temperature zone of the continuously cast slab,then extend to transverse corner cracks during bending and straightening process.Moreover,high-temperature mechanical properties of SS400B was investigated,and based on the results,"intensified cooling" was put forward to prevent the formation of transverse corner cracks in slabs.

Comparative Research on the Properties of Welded Casing and Seamless Casing

Wang Jun, Wang Yan, Zhang Feng, He Shilei, Wei Feng, Li Zhoubo, Wang Liang, Li Lei

2013, 34(4): 99-103. doi: 10.7513/j.issn.1004-7638.2013.04.019

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The dimensional accuracy,residual stress and collapsing resistance of HFW casing,SEW casing and seamless casing were studied in this paper.The results show that compared with seamless casing,HFW and SEW casings are much better in the aforementioned characteristics.Moreover,employment of SEW process can properly solve the problems of low impact toughness and poor corrosion resistance at welded joints.Therefore,using SEW casing can avoid low collapsing resistance of seamless casing when other factors are fixed,and thus can completely meet the requirements of oilfield customers.

Influence of Deformation Temperature on Hot Ductility of As-cast Austenitic Stainless Steel

Hou Guoqing, Zhu Liang

2013, 34(4): 104-109. doi: 10.7513/j.issn.1004-7638.2013.04.020

Abstract(13) PDF(1)

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The influence of deformation temperature on the hot ductility of as-cast and hot-rolled austenitic stainless steel Cr15Mn9Cu2NiN is investigated via high-temperature tensile tests.Results show that at 1 250℃,reduction of areas(RA) in both as-cast and hot-rolled specimens are higher than 85%.As the deformation temperature decreases,hot ductility of as-cast specimens drops rapidly while there is no obvious variation for that of hot-rolled specimens.As the deformation temperature decreases to 900℃,RA of as-cast specimens is just around 45%.Analyses suggest that microstructures in as-cast specimens are coarse columnar grains,deformation coordination ability of which falls fast with decreasing deformation temperature,leading to strain concentration at grain boundary or phase boundary,and then resulting in crack nucleating and rapid reduction of hot ductility.For hot-rolled specimens,the microstructures are homogeneous and fine equiaxed grains with excellent ability of deformation coordination; during deformation,the strain uniformly distributes in all the grains,which brings about higher hot ductility.

Vanadium Microalloyed Forging Steel

Li Yu, David Milbourn

2013, 34(4): 110-117. doi: 10.7513/j.issn.1004-7638.2013.04.021

Abstract(17) PDF(1)

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Vanadium microalloyed steel forgings provide lightweight,high performance and cost effective solutions for many critical automotive components in the drivetrain and chassis of modern cars and trucks.These high strength steel forgings are already widely used in regions with developed automotive industries such as Europe,Japan and North America,and they play an important role in new vehicle designs required to meet increasingly stringent weight and emission targets.Developing countries and regions will also present a significant opportunity for adoption of this technology as indigenous automotive production expands and the best engineering solutions are applied.The majority of these forgings are produced from medium carbon steels with small additions of vanadium to provide substantial precipitation strengthening of the controlled cooled ferrite-pearlite microstructure.The aim of this paper is to provide an introduction to the essential aspects of this important technology by providing an overview of the historical development,basic metallurgy,processing,properties and typical applications.

2013, 34(4): 118-120.

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2013 Vol. 34, No. 4