钢铁钒钛

Extraction of Valuable Components from Alkali Fused Blast Furnace Slag Containing High Concentration of Titanium by Two Leaching Methods

Wang Yan, He Siqi, Dai Qunwei

2016, 37(5): 1-8. doi: 10.7513/j.issn.1004-7638.2016.05.001

Abstract(187) PDF(6)

Abstract:
Aiming at the problems of high energy consumption and high economic cost for the extraction of TiO₂ from blast furnace slag containing high concentration of titanium by alkali fusion,the slag was roasted with sodium hydroxide at a lower temperature to extract Si and Al components firstly making TiO₂ enriched in the slag,then the TiO₂ component was abstracted by dilute sulfuric acid.The effects of alkali fusion conditions on the extraction rate of SiO₂ and Al₂O₃ from blast furnace slag containing high concentration of titanium respectively by two leaching processes,air cooling-water leaching and water quenching were investigated.Furthermore,the influence of acidolysis conditions on TiO₂ extraction was also studied in this paper.Under the optimum conditions of alkali fusion at 500℃ for 150 min with 1.5 of alkali addition coefficient,the extraction rate of SiO₂ and Al₂O₃ were separately 56.41% and 89.00% by air cooling-water leaching while respectively 63.45% and 86.25% by water quenching.The acidolysis rate of TiO₂ was 91.21% at the conditions of 50% for mass fraction of sulfuric acid,1.25~1.5:1 for mass ratio of acid to slag,160~170℃ and 2.0 h respectively for temperature and time of acidolysis process.

Investigation on Chlorination Characteristics of Panzhihua Titanium Slag in Molten Salts

Li Kaihua, Li Liang, Miao Qingdong, Sheng Zhuo

2016, 37(5): 9-14. doi: 10.7513/j.issn.1004-7638.2016.05.002

Abstract(51) PDF(3)

Abstract:
The chemical compositions,phase compositions and mineral structures of Panzhihua titanium slags with 74%,78% and 85% grade were respectively studied in this paper,mainly focusing on the differences of chemical reactions,heat release and system heat balance control in molten salts chlorination process for the 3 mentioned titanium slags.It is indicated that there is no significant difference in phase compositions for the titanium slags,while the contents of anosovite,rutile and transition phase for the slags are different which leads to 21.9% of heat release less than 74% titanium slag and 9.9% of heat release more than 85% titanium slag,respectively compared with 78% titanium slag in molten salts chlorination.The amount of ore pulp back to the furnace based on the thermal equilibrium calculation for the chlorination furnace,coincides with the practical application in chlorination process.

Study on the Structure of Vanadium-containing Phase and Its Evolution during the Calcination and Leaching Processes for Calcification Extraction of Vanadium

Shi Zhixin

2016, 37(5): 15-19. doi: 10.7513/j.issn.1004-7638.2016.05.003

Abstract(60) PDF(3)

Abstract:
The difference of phase transition during the processes of calcium roasting and acid leaching of vanadium slag has a significant influence on the total vanadium conversion rate.The microstructure and morphology of the vanadium-containing phases,and trend of vanadium during those phases in vanadium slag,clinker and residue were analyzed.The results show that the vanadium spinel with initial smooth and dense polygon structure is gradually oxidized into porous state,and finally forms concavo-convex granular iron oxides and short columnar pseudobrookite.The vanadium element initially enriched in vanadium spinel,gradually transfers into calcium vanadate,iron oxides,pseudobrookite and silicate phases.The most significant change in the acid leaching process is that the concavo-convex vanadium-containing oxides(iron oxides,pseudobrookite and calcium vanadate) in clinker change into hollow pseudobrookite phase step by step,and most of the vanadium has been extracted by sulfuric acid with the residual vanadium mainly remained in iron oxides,pseudobrookite and calcium silicate phases.

Removal of Iron from Acid Leaching Solution of Vanadium Slag by Complexation

Zhou Weihua, Li Zhenzhen, Duan Meng, Lü Guozhi

2016, 37(5): 20-24,34. doi: 10.7513/j.issn.1004-7638.2016.05.004

Abstract(58) PDF(1)

Abstract:
In view of the high energy consumption in the process of roasting and low recovery rate of vanadium for the current vanadium extraction technologies,a new non-roasting process of pressure leaching of vanadium slag with waste acid from titanium dioxide production was put forward,and the extraction separation process of vanadium and iron in the leaching solution was investigated.The results show that the single-stage extraction rate of iron can reach 34.15% and the extraction rate of vanadium is less than 2% with up to 42.54 of separation coefficient for iron to vanadium,at pH=-0.86,25% of volume fraction for extraction agent N235,5:1 of volume ratio for organic to aqueous phase(V_O/V_A),10 min of shaking time and 140 g/L of Cl^- concentration by adding NaCl.The process can realize an effective separation of iron from the high iron-containing vanadium leaching solution.

Experimental Research on Deep Reduction and Grinding Separation of Low Ti-bearing Vanadium-titanium Magnetite

Li Juyan, Tang En, Qin Cen, Zhou Qiang, Fan Xiaogang, Wang Jun

2016, 37(5): 25-29. doi: 10.7513/j.issn.1004-7638.2016.05.005

Abstract(57) PDF(1)

Abstract:
Experimental research on deep reduction and grinding separation of a certain low Ti-bearing vanadium-titanium magnetite was conducted.The results show that the critical conditions for inhibiting the reduction of vanadium are reduction at 1 050℃ for 10 h.The reduction of vanadium-titanium magnetite can be enhanced by additives and extension of reduction time.Borax can efficiently promote the reduction of the vanadium-titanium magnetite,and the metallization rate of product reaches 98.21% with 3% borax added.However,inhibitory effects on reduction were observed with CaF₂ in the experiments.Low intensity magnetic separation and deep grinding are beneficial to separate Fe and V.

Study on Ramming Technology of the Casting Mold for Ferrovanadium Smelting

Yu Bin

2016, 37(5): 30-34. doi: 10.7513/j.issn.1004-7638.2016.05.006

Abstract(49) PDF(1)

Abstract:
Ramming characteristics of the casting mold,which is suitable for ferrovanadium smelting by tilting furnace,was studied.The effects of magnesia particle size distribution,brine ratio,ramming time,corundum slag ratio and baking program on the amount of seeping ferrovanadium in casting mold and its vanadium content were investigated.The results indicate that vanadium loss in casting process decreases with increase in magnesia particle size and ramming time while increases with the increasing corundum slag ratio.Meanwhile,vanadium loss decreases at first and increases subsequently with increase in brine ratio.The baking program has nearly no effect on vanadium loss in the experiments.In this study,the vanadium loss is calculated to be 3.16 kg when the weight of seeping alloy is 131 kg with 2.43% of vanadium content at the optimal experimental conditions for 8:1 of magnesia particle size ratio(3~8 mm/0~3 mm),2.5:1of brine ratio,60 min of ramming time,and 0~500℃ for 2.0 h,500℃ for 2.0 h,500~800℃ for 2.0 h,800℃ for 4.0 h of baking program.

Preparation of Bismuth Vanadate Pigment by Solid-state Calcination

Du Guangchao, Yin Danfeng, Sun Chaohui, Jing Han, Chen Haijun, Tang Hongjian, Yu Bin, Wang Tanglin

2016, 37(5): 35-42. doi: 10.7513/j.issn.1004-7638.2016.05.007

Abstract(151) PDF(7)

Abstract:
Bismuth vanadate pigment was synthesized by solid-state reaction,and the influences of raw materials,calcination temperature and time on the phase compositions,particle size,specific surface area and chromatic property of the obtained bismuth vanadate were investigated in this paper.It is indicated that a more moderate preparation condition can be satisfied using NH₄VO₃ and Bi(NO₃)₃·5H₂O as raw materials.Bismuth vanadate possessing a higher phase purity,more excellent particle size distribution and specific surface area can be obtained by calcination at 500℃ for 12 h,with a chromaticity coordinates of L^*=84.91,a^*=1.18,b^*=85.87 and c^*=85.88 for the product demonstrating a superior pigmentary performance to the bismuth vanadate sold around the market.

Evolution of Inclusions in Welding Wire Steel Containing Titanium

Liu Shanxi, Zhang Caijun, Lü Da, Ma Degang, Li Shuo

2016, 37(5): 43-49. doi: 10.7513/j.issn.1004-7638.2016.05.008

Abstract(70) PDF(3)

Abstract:
In order to develop welding wire steel containing titanium named ER70S-G,the quantity,size and species of inclusions in the melting process were studied.The results show that in the process of refining,the quantity of inclusions in the steel with equivalent diameter reduces gradually,and the number of inclusions per mm² with equivalent diameter of 5 μm decreases from 19.78 to 1.66 in the tundish.The average diameter of inclusions gradually decreases to 2.05 μm in the refining process.At the beginning of refining,the main inclusions in the steel are Mn O-SiO₂,and they transform into CaO and MgO before adding ferrotitanium.After adding ferrotitanium,Al₂O₃-Ti₂O₃-MgO is the main inclusions of the steel in tundish.

Effects of Complex Vanadium Carbide and Graphene Addition on the Properties of CNC Machine Tool Steel

Shu Dongpeng

2016, 37(5): 50-53. doi: 10.7513/j.issn.1004-7638.2016.05.009

Abstract(51) PDF(1)

Abstract:
The wear resistance and thermal fatigue properties of CNC machine tool steel W18Cr4V with various content of vanadium carbide and graphene were tested and analyzed.The results show that complex adding vanadium carbide and graphene was better for improving the wear resistance and thermal fatigue property of W18Cr4V steel than single addition.Complex adding vanadium carbide of 1.5% and graphene of 1.5% could decrease the wear loss volume of W18Cr4V steel by 81%,and improve the thermal fatigue grade from grade 9 to 2 grade.

Effects of Ti,V and Nb on Microstructure of Welding Heat-affected Zone for DH36 Steel

Li Shaoying, Han Yihua, Zhu Liguang, Li Kun, Gao Aimin

2016, 37(5): 54-59. doi: 10.7513/j.issn.1004-7638.2016.05.010

Abstract(47) PDF(1)

Abstract:
Vacuum smelting and rolling of DH36 high strength ship plate steel were carried out in laboratory by adding different micro-alloying elements.The effects of micro-alloying elements Ti,V and Nb on the microstructure of welding heat-affected zone for DH36 were investigated by welding thermal simulation tests respectively with 50 and 100 kJ/cm of line energy,using Gleeble 3500 testing machine.The results show that in the welding heat-affected zone of DH36,Ti transforms into oxides inducing acicular ferrite which pins the austenite grain boundaries,while V and Nb do not generate inclusions.

Effect of Heat Treatment on the Performances of Passivation Machine Drill Made of Yttrium-containing W18Cr4V Steel

Cheng Qiong, Yao Zhao

2016, 37(5): 60-64. doi: 10.7513/j.issn.1004-7638.2016.05.011

Abstract(82) PDF(1)

Abstract:
Focusing on the inferior impact and thermal fatigue performances of drill made of W18Cr4 V steel which are often caused by serious segregation of carbides and the existence of large carbides particles in the steel,different annealing temperatures and quenching processes were employed to carry out the heat treatment for passivation machine drill made of yttrium-containing W18Cr4 V steel,and the microstructure,impact properties and thermal fatigue performances of the drill were respectively analyzed by SEM,impact and thermal fatigue tests.The results show that with increasing annealing temperature,both the impact properties and thermal fatigue performances of the drill are firstly improved then degraded.Step quenching is more conducive to the improvement of impact properties and thermal fatigue performances of the drill.For the passivation machine drill made of yttrium-containing W18Cr4 V steel,the optimal annealing temperature is 900℃ with optimum step quenching of 1 450℃×10 min+1 250℃×20 min.

Effect of V-Ti Solid Solution Content on the Properties of Surface Modified Mold

Ji Yeyi, Lu Baoshan, Sun Shujuan, Li Qiangwei

2016, 37(5): 65-69. doi: 10.7513/j.issn.1004-7638.2016.05.012

Abstract(35) PDF(2)

Abstract:
3Cr2W8V die was surface modified by adding different contents of V-Ti solid solution reinforced phase in the laser cladding powder,and the wear resistance and thermal fatigue properties of the modified die were tested and analyzed.The results show that adding V-Ti solid solution could improve the wear resistance and thermal fatigue properties of the surface modified die.The optimized content of V-Ti solid solution is 15%.Compared with those of the die without V-Ti solid solution in the laser cladding powder,the wear volume of the surface modified die decreases by 63%,and its thermal fatigue crack level changes from 7 to 2.

Study on the Compositions and Structure Characteristics of a Vanadium-titanium Magnetite from Panxi Region

Li Junhan, Sun Ning, Luo Jinhua

2016, 37(5): 70-75. doi: 10.7513/j.issn.1004-7638.2016.05.013

Abstract(242) PDF(14)

Abstract:
The chemical analysis,spectral analysis,X-ray diffraction phase qualitative analysis,optical microscope,scanning electron microscope and MLA analysis were employed to systematically study the chemical and mineral compositions of a vanadium-titanium magnetite(V-Ti magnetite) from Panxi area in this paper.The results indicate that the V-Ti magnetite is mainly consisted of iron,titanium and vanadium,etc.,with about 31% TFe,11% Ti O₂ and 0.5% V₂O₅ satisfying the industrial utilization standards overall.Besides the iron,titanium and vanadium all of which are the major components for utilization of this ore,a lot of beneficial associated elements(e.g.chromium,manganese,cobalt,nickel and copper,etc.) are contained in the V-Ti magnetite.The main metallic minerals in this ore are titanium-magnetite(43.09%~45.09%) and ilmenite(11.67%~13.17%) which can be used for industrial beneficiation of iron concentrate and titanium concentrate,respectively.Moreover,the V-Ti magnetite also contains some sulfide minerals such as pyrite,galena,sphalerite and chalcopyrite,etc.which can form the sulfur cobalt concentrate after beneficiation.The V-Ti magnetite is mainly of disseminated structure with subhedral-anhedral,embedded,sideronitic,metasomatic relict and solid separation textures.The results confirm the materials basis for the comprehensive utilization of this vanadium-titanium magnetite and make clear the structure characteristics of this ore,which provides important basic information for the establishment of beneficiation processes of this ore.

Study on the Recycle Technology of the Slag from Refining Process of TiCl₄

Li Liang, Zhou Li, Li Dongqin, Du Ming, Long Panzhong, Lu Ping

2016, 37(5): 76-79. doi: 10.7513/j.issn.1004-7638.2016.05.014

Abstract(43) PDF(1)

Abstract:
The recycle of slag produced during the refining process of TiCl₄ in the sponge titanium factory was studied.Based on the analysis of the element compositions and physical properties of the slag from the refining process of TiCl₄,a process of preparing vanadium slag by high temperature calcination of the slag was proposed.The experimental conditions of the calcination temperature,calcination time and the material particle size were studied.The results show that vanadium slag with 8%~12% of TV content and less than 0.3% Cl can be obtained by calcination of the slag from the refining process of TiCl₄ at T ≥ 600℃ for more than 2 h.The recovery rate of V is 95% and the emission rate of Cl reaches 99%.

Effects of Magnesium Oxide on Properties of Ceramics Made from Vanadium and Titanium Waste Residue

Chen Jie, Xu Jianan, Zhou Yang, Zhang Ping, Yang Weizhong

2016, 37(5): 80-83. doi: 10.7513/j.issn.1004-7638.2016.05.015

Abstract(42) PDF(1)

Abstract:
The domestic ceramics was prepared using industrial vanadium and titanium waste residue as raw material,and the effects of additive magnesium oxide(MgO) on the ignition loss,linear shrinkage,water absorption,porosity and rupture modulus of the ceramics were investigated with the optimum parameters for 10 min of grinding time and 1 100℃ of sintering temperature.Furthermore,the phase compositions and microstructure of the ceramics were also analyzed by XRD and SEM,respectively.The results show that with adding 0.6% MgO the rupture modulus of the obtained ceramicscan be significantly increased and the water absorption and porosity of the ceramics are both decreased,and the main phases of the ceramics are consisted of quartz,anorthite and chrome-magnesium spinel.The usage amount of vanadium and titanium waste residue can be increased which realizes the recycle of waste resources by adding MgO,according to this research.

Research on Recovery of Iron from Natural-basicity Carbon-containing Pellets of Jarosite Residue

Cao Xiaoen, Hong Lukuo, Zhou Hemin, Tang Xiaofang, Qi Yuanhong

2016, 37(5): 84-90. doi: 10.7513/j.issn.1004-7638.2016.05.016

Abstract(60) PDF(1)

Abstract:
Jarosite residue is a solid waste originating from iron removal process of zinc hydrometallurgy,containing a certain amount of Fe and other valuable metals.In order to recovery Fe,the rotary hearth furnace direct reduction-melting process had been developed to process carbon-containing pellets of jarosite residue.The effect of the process parameters on Fe recovery from jarosite residue was studied,through direct reduction of natural basicity carbon-containing pellets of jarosite residue.At the same time,the pilot plant test has been carried out with rotary hearth furnace.The optimum conditions from experimental test are as follows:reduction temperature of 1 100℃,reduction time of 30 min,C/O=1.2.Under these conditions,the metallization rate of carbon-containing pellets of jarosite residue reaches 90.6%,the metallization rate of pilot plant test is 75%,the comprehensive recovery rate of iron is 85%.

Study on Fluidity of BF Slag with High Alkali and TiO₂ Content

Tian Ye, Chen Shujun, Lü Qing, Sun Yanqin, Qie Yana, Liu Xiaojie

2016, 37(5): 91-95,111. doi: 10.7513/j.issn.1004-7638.2016.05.017

Abstract(57) PDF(2)

Abstract:
The fluidity of BF slag deteriorates as the usage proportion of the low-cost imported iron ore becomes larger,because of the higher alkali metal and TiO₂ contents,therefore,it is necessary to determine the influence of alkali metal and TiO₂ on BF slag fluidity.Detailed research results show that slag viscosity increases with the increase of TiO₂ content,and decreases with the increase of alkali metal content.The binary basicity affects the viscosity and the melting temperature significantly.The proportion of imported iron ore containing TiO₂ to toal input ore should not exceed 30%,and the composition of slag should be controlled as follows:the TiO₂ content is 3.2%,the alkali metal content is 0.86%,the binary basicity is 1.05,the MgO content is 10.46%.After considering these conditions,the resulted slag fluidity can be improved.

Effect of Hydrogen-rich on Reduction of Low Titanium Pellets in the Lumpy Zone

Zhang Qi, Liu Ran, Liu Chaoqing, Li Yanjiang, Li Jianpeng, Lü Qing

2016, 37(5): 96-101. doi: 10.7513/j.issn.1004-7638.2016.05.018

Abstract(51) PDF(1)

Abstract:
Based on the blast furnace gas-injection,the effects of different H₂ contents and temperatures on the reduction of ore in the low temperature lumpy zone are studied.The result shows that,when the temperature of reduction is 900℃,the reduction rate increases with an increase in the H₂ content.When H₂ content is fixed,the reduction rate increases with temperature.The main phases are Fe and small amount of(Mg,Fe)(Fe,Ti)O₃,(MgAl₂O₄),(Mg₂SiO₄) after reduction.With increasing temperature,the(Mg,Fe)(Fe,Ti)O₃ disappears firstly,then the(MgAl₂O₄) and(Mg₂SiO₄) decreases,and reducing capacity of H₂ significantly improves,the oxygen loss rate of iron ore increases,the resulted iron aggregates and some small pores would appear in the pellets.

Design Features of 1750m³ Blast Furnace in Xichang Steel and Vanadium Co. of Angang Group

Li Yunhua, Li Jiafu

2016, 37(5): 102-105. doi: 10.7513/j.issn.1004-7638.2016.05.019

Abstract(33) PDF(1)

Abstract:
The paper summarizes the design features of 3×1 750 m³ BF stack in Xichang Steel and Vanadium.The blast furnace is a thin wall furnace shape,suitable for smelting vanadium titanium magnetite ore.Equipped with compound hearth lining with heat insulation technology,moderate cooling intensity of double snakelike tube of nodular cast iron stave,subsection cooling water system,and lots of measurement instruments,the designed blast furnace is at world class level in terms of vanadium titanium magnetite ore smelting.

Simulation on Temperature Distribution in Reduction Zone of Iron Ore Hydrogen DR Shaft Furnace

Bai Minghua, Han Shaofeng, Xu Kuan, Li Luye, Lü Jianchao, Zhang Weiya

2016, 37(5): 106-111. doi: 10.7513/j.issn.1004-7638.2016.05.020

Abstract(131) PDF(7)

Abstract:
Based on the technical and process parameters of BL shaft furnace,a gas-solid phases heat transfer model was built for simulation together with Fluent software.The pellets were taken as porous media and movement of pellets had been simulated through sliding mesh method.Reduction reactions involved in the calculation using the three-step reaction,we can get the temperature field and thermal efficiency in the reduction zone of hydrogen DRI shaft furnace.The results showed that with the increase of the hydrogen flow,the temperature gradient of reduction zone became narrow,the temperature of the reduction gas at the outlet was higher and the thermal efficiency of the reduction gas decreased.The percentage of reduced products as a function of distance from shaft inlet can be simulated.It indicated that the simplified gas-solid heat transfer model can be used to analyze the temperature field and reactants in the reduction zone of hydrogen DRI shaft furnace.

Numerical Simulation on Optimization Design of Constructional and Technical Parameters of 65 t Ladle

Yang Zhaojun, Ceng Yanan, Li Junguo

2016, 37(5): 112-117. doi: 10.7513/j.issn.1004-7638.2016.05.021

Abstract(61) PDF(1)

Abstract:
According to the practical conditions of 65 t ladle at Tangshan Iron & Steel Corp.,numerical simulation of flow field,death zone and mixing time of the ladle has been carried out by Fluent software.The results were verified with the cold model simulation,which provided theoretical and experimental basis for the optimization of constructional and technical parameters of bottom blowing.Higher velocity zone of the molten steel concentrated at the high-speed gas-liquid jet area and the top of the ladle,while the death zone located at the bottom of the ladle.Under the condition of 100 L/min bottom blowing,the volume ratio of the death zone was small as the intersection angle and the center distance of bottom blowing were 180° and 0.6R,respectively.Under this constructional condition,the volume ratio of death zone and the mixing time were declined with the increasing of the bottom blowing flow.The changing tendency of mixing time was verified by the cold model experiment.The mixing time obtained by numerical simulation was consistent with that determined by the cold simulation,which proved the reliability of the numerical simulation.

Stress-strain Behavior of Ferrite and Bainite with Nano-precipitation in Low Carbon Steels

Naoya Kamikawa, Kensuke Sato, Goro Miyamoto, Mitsuhiro Murayama, Nobuaki Sekido, Kaneaki Tsuzaki, Tadashi Furuhara

2016, 37(5): 118-132. doi: 10.7513/j.issn.1004-7638.2016.05.022

Abstract(63) PDF(1)

Abstract:
We systematically investigate stress-strain behavior of ferrite and bainite with nano-sized vanadium carbides in low carbon steels; the ferrite samples were obtained through austenite/ferrite transformation accompanied with interphase precipitation and the bainite samples were via austenite/bainite transformation with subsequent aging.The stress-strain curves of both samples share several common features,i.e.high yield stress,relatively low work hardening and sufficient tensile elongation.Strengthening contributions from solute atoms,grain boundaries,dislocations and precipitates are calculated based on the structural parameters,and the calculation result is compared with the experimentally-obtained yield stress.The contributions from solute atoms and grain boundaries are simply additive,whereas those from dislocations and precipitates should be treated by taking the square root of the sum of the squares of two values.Nanosized carbides may act as sites for dislocation multiplication in the early stage of deformation,while they may enhance dislocation annihilation in the later stage of deformation.Such enhanced dynamic recovery might be the reason for a relatively large elongation in both ferrite and bainite samples.

Effect of Heat Input on Microstructure and Impact Property of Heat Affected Zone for X100 Pipeline Steel

Chen You, Li Liejun, Huo Xiangdong, Chen Songjun, Peng Zhengwu

2016, 37(5): 133-138. doi: 10.7513/j.issn.1004-7638.2016.05.023

Abstract(144) PDF(4)

Abstract:
The effects of different welding heat input on microstructure and mechanical properties of heat affected zone in X100 pipeline steel was studied by means of welding thermal simulation technology,microstructure analysis and impact test.The results showed that when the heat input is greater than 45 kJ/cm,the microstructure is mainly composed of granular bainite,and M/A island is irregular large block with sharp corners,leading to the decrease of material toughness; when the heat input is 15~35 kJ/cm,the microstructures is mainly composed of lath bainite and a small amount of acicular ferrite,with fine M/A island distributed in the ferrite matrix,which does not deteriorate on the toughness,and the resulted impact absorbed energy is at the highest value.When the heat input is less than 15 kJ/cm,martensite appears in microstructure,the hardness of HAZ is the highest but the toughness decreases.

Effect of Rare Earth Treatment on Inclusion of E36 Slab for Shipbuilding

Wu Chunhong, Sun Lefei, Lai Chaobin, Deng Zhihao, Fu Qingxia, Yuan Chuanquan

2016, 37(5): 139-146. doi: 10.7513/j.issn.1004-7638.2016.05.024

Abstract(29) PDF(2)

Abstract:
In order to control the shape of inclusions in steel liquid and determine the rare earth Y and Ce and O,S reaction sequenceand the formation of the rare earth inclusions,the rare earth degeneration inclusion in E36 ship plate steel had been investigated through thermodynamic calculation and experimental study,and the typical inclusion had been observed using scanning electron microscopyand EDS.It is found out that Ce has more tendency to react with O and S than Y.The sequenceof the rare earth inclusions formed are Re₂O₃,Re₂O₂ S,Re₂S³.The dominant rare earth compound inclusions are sizes at~15 μm and~50 μm.Compared with the inclusion of steel without rare earth addition,the inclusion size of RE treated steel reduces by 20~55 μm and its shape are more globular.Rare earth oxides mostly locates on the 1/4 thickness of upper surface and rare earth sulfur oxides locates on the 1/2 thickness.Rare earth addition can improve the morphology and size of inclusion,and thusimprove the performance of the steel.

Research on the Mechanism of Edge Layer on Non-oriented Electrical Steel with TSCR

Du Hongbo, Dong Xinxin, Zhang Jie, Song Haiwu, Sun Lu

2016, 37(5): 147-152. doi: 10.7513/j.issn.1004-7638.2016.05.025

Abstract(40) PDF(1)

Abstract:
The non-oriented electrical steel has the advantages of high magnetic induction and energy conservation via thin slab casting and rolling(TSCR),but it usually appears layers upon the edge of steel strip.Mechanism of the edge layer had been investigated,in order to improve edge quality and product yield as well.The used strip is TGW600,which is produced by TCSR in Tang Steel.The influencing factors of the edge defect are researched,including the reason of intermediate slab fold,simulating deformation in grains,high temperature strength and its comparison with other grades,as well as expansion curves.It is found out that the uneven deformation of grains at rolling direction and cross direction contributes to the edge layer,there is unobvious phase process,and the microstructure is ferrite at the test temperature window,therefore,there is no ductility trough.It is suggested that solutions to this defect are promoting recrystallization and controlling the shape of strip during hot rolling.

Analyze and Control for Peeling Defects on the Internal Surface of JS25Mn Steel Tube

Li Hongguang, Chen Tianming, Chen Liang, Guo Dianrong

2016, 37(5): 153-156. doi: 10.7513/j.issn.1004-7638.2016.05.026

Abstract(61) PDF(2)

Abstract:
Peeling defect on internal surface of JS25Mn steel tube have been analyzed in this paper.Highmelting non-metallic inclusions containing titanium have been found in steel,and low-melting non-metallic inclusion segregated in the center porosity defective area of billets',which are the major factors that lead to peeling defects.The purity degree have been improved after RH vacuum-treatment for melting steel,and after optimizing and modifying casting process,the internal quality of billets have been improved,and the peeling defects issue have been resolved effectively.

Analysis and Controlling of Crack on 60Si2MnA Steel

Gao Ju, Ding Zhijun, Li Hui

2016, 37(5): 157-161,168. doi: 10.7513/j.issn.1004-7638.2016.05.027

Abstract(56) PDF(2)

Abstract:
In view of the high crack rate of 60Si2MnA steel,a systematic research on the steel crack's shape characteristics,formation causes,influencing factors,controlling measureshad been investigated,considering the practical producing and smelting process.It is found out that the internal cracks in60Si2MnA steel are mainly caused by large inclusions in the steel.The inclusions consist of compound complex of Al,Mg,Ca,and Si.The high contents of Al,Caand MgO in molten steel,together with the serious erosion of ladle and large casing refractory,are the main causes of large inclusions.By means of replacing ordinary silicon iron with low-Al silicon iron,using high quality refractory,limiting the empty time of ladle to less than 1.5 hours,replacing the large bundle casing for each furnace,and using double covering agent for tundish,the internal crack rate can be reduced from 0.53% to 0.11%.

Analysis and Improvement of Edge Linear Defects of Tinplate

Zhou Xun, Ai Jiaojian, Wang Xiaodong, Xu Haiwei, Li Rui, Xia Yinfeng, Wang Jiangong, Yang Xiaohe, Sun Chaofan, Gao Xiaoli, Wei Lianqi

2016, 37(5): 162-168. doi: 10.7513/j.issn.1004-7638.2016.05.028

Abstract(36) PDF(1)

Abstract:
The growth mechanism and inherited characteristic of linear defect at the edge of hot rolling steel plate has been investigated in details.Based on the analysis,the effect of rolling process were discussed.SEM and EDS were used to analyze the morphology,component and structure of the defect.The result showed that,contributors to linear defect were inclusions from steel making process,the edge shell and oxide scale from hot rolling process and scratch from leveling process.The edge shell defect could be controlled by roll crown adjustment,,the inclusion scratch and oxide scale could be improved by series of process control technology.The edge linear defect proportion decreased by more than 70%,and the surface quality had been improved significantly.

2016 Vol. 37, No. 5