钢铁钒钛

Research on Simultaneous Extraction of Vanadium and Chromium from High Chromium Vanadium Slag by Sub-molten Salt Method

Pan Ziwei, Zheng Shili, Wang Zhongxing, Wang Shaona, Du Hao, Zhang Yi, Xie Hua

2014, 35(2): 1-8. doi: 10.7513/j.issn.1004-7638.2014.02.001

Abstract(20) PDF(1)

Abstract:
In order to realize efficient and low-cost low-temperature simultaneous extraction of vanadium and chromium from high chromium vanadium slag,NaOH sub-molten salt liquid phase oxidation was employed according to phase of the slag.After the influences of reaction temperature of NaOH sub-molten salt system,NaOH-to-ore mass ratio and speed of stirring on vanadium extraction were studied,the optimum process parameters were obtained.With the reaction temperature of 220℃,NaOH concentration of 85%,NaOH-to-ore mass ratio of 10:1,stirring speed of 950 r/min,atmospheric oxygen flow of 1 L/min and reaction time of 6 h,the leaching rates of vanadium and chromium reached 95% and 90% or above respectively,which indicates the realization of comprehensive utilization of vanadium slag.

Research on Leaching Vanadium from Vanadium and Titanium-bearing Tailings Produced in Reduction,Grinding and Separation of Vanadium-bearing Titaniferous Magnetite

Guo Yufeng, Sui Yulei, Jiang Tao, Lü Yanan

2014, 35(2): 9-14. doi: 10.7513/j.issn.1004-7638.2014.02.002

Abstract(22) PDF(1)

Abstract:
A comparative research on the two vanadium extraction processes of sodium roasting and acid leaching is carried out in order to find a suitable way to extract vanadium from vanadium and titaniumbearing tailings generated in reduction,grinding and separation of vanadium-bearing titaniferous magnetite.The research shows that with the application of the sodium roasting process,the leaching rate of vanadium is only about 18% while with the acid leaching process,it can be higher than 70%.It can be concluded that it is suitable to employ the acid leaching process for vanadium extraction from the vanadium and titanium-bearing tailings.Material characteristics together with physical and chemical variation in the process of vanadium extraction indicate that through the process of sodium roasting,vanadium could be wrapped with complex insoluble compounds during roasting while it won't happen during pre-oxidation roasting of the acid leaching process,which is the main reason for its higher vanadium leaching rate.

Comparative Research on Extracting Vanadium from Vanadium Slag by Molten Method and Roasting Method

Zheng Quan, Song Wenchen, Li Kun, Li Hong

2014, 35(2): 15-19. doi: 10.7513/j.issn.1004-7638.2014.02.003

Abstract(21) PDF(0)

Abstract:
Comparative experiments of extracting vanadium by the molten method'(namely,the method of direct oxidation and sodium treatment of molten vanadium slag to produce water-soluble sodium vanadate) and roasting method were done in the laboratory for maximizing vanadium yield from molten vanadium slag with the new molten method.The result showed that vanadium leaching rate of the molten method was lower than that of the roasting method,and XRD analysis showed that oxidation degree of clinker produced by the molten method was lower than that of the clinker produced by the roasting method.Through analyzing,it was believed that excess temperature and short oxygen blowing time were the main reasons for the result.Some improvement measures for the molten method including reducing temperature while blowing oxygen and extending the time of oxygen blowing were put forward.As a result,the vanadium leaching rate of the molten method attained the same level of the roasting method.

Research on Preparation and Application of High-density Granular V₂O₃

Chen Donghui, Li Lanjie, Shi Lixin

2014, 35(2): 20-25. doi: 10.7513/j.issn.1004-7638.2014.02.004

Abstract(21) PDF(0)

Abstract:
The industrial vanadium trioxide is powdery with bulk density of 0.6~1.2 g/cm³,which is not good for recovering vanadium in the following vanadium alloy smelting process.Due to the high melting point of V₂O₃,only the physical method could be employed to increase the V₂O₃ density.In this paper,the nonslurry pelletizing process is introduced.Granular V₂O₃ with high relative bulk density can be acquired by reducing the roller's rotation speed and increasing the roller's pressure,etc.The bulk density of the granular V₂O₃ increases to 1.7~2.1 g/cm³ through employing 5 exhaust processes and exerting 120 N/cm² of mechanical molding pressure during pelletizing.V yield increases from 89%~92% to 93%~96% or even higher by using high-density V₂O₃ in the FeV metallurgy process.The V content in FeV alloy also slightly increases.

Optimization Experiments on Preparation of TiO₂ as a SCR Catalyst Carrier from Ilmenite

Zhang Qianyun, Zhong Zhaoping, Yao Jie, Zhu Lin

2014, 35(2): 26-30. doi: 10.7513/j.issn.1004-7638.2014.02.005

Abstract(36) PDF(0)

Abstract:
Preparation of titanium dioxide(TiO₂) by solid-phase digestion of ilmenite in sulfuric acid has a high acidolysis rate.Since Ethylene Diamine Tetraacetic Acid(EDTA) is a widely used complexing agent,appropriate amount of EDTA added during hydrolysis of titaniferous solution can be beneficial to the separation of titanium and iron.The mechanical and cavitation effects of ultrasound can contribute to further remove a trace amount of impurity ions.The effects of EDTA and ultrasound on TiO₂ are analyzed by the X-ray fluorescence energy disperse spectroscopy,BET specific surface area analyzer,porosity analyzer,and scanning electron microscope.DeNOXperformances of SCR catalysts taking different TiO₂ as carriers are tested.The results show that the addition of EDTA can restrain the hydrolysis of Fe³⁺,thus shorten the whole process and improve TiO₂ purity; ultrasound is helpful to remove impurity ions,and can reduce the particle sizes of TiO₂ and optimize their dispersion properties at the same time.The SCR catalyst utilizing the optimized TiO₂ as a carrier presents better catalytic activity.

Preparation of Porous TiO₂ Photocatalyst by Hydrothermal Crystallizing Process

Pu Hong, Tian Congxue

2014, 35(2): 31-34,55. doi: 10.7513/j.issn.1004-7638.2014.02.006

Abstract(21) PDF(0)

Abstract:
Porous TiO₂ photocatalyst was prepared via hydrothermal crystallization of industrial metatitanic acid,and the effects of crystallization time on structures and properties of porous TiO₂ were also investigated.The samples so prepared were characterized by XRD,SEM,XPS,FT- IR and nitrogen absorption-desorption,and its photocatalytic activity was evaluated by photocatalytic degradation of methylene blue.With the extension of the crystallization time,the photocatalytic activity increased initially and then gradually decreased.Porous TiO₂ crystallized at 140℃ for 2 h showed the best photocatalytic activity,with the degradation rate of 81.18% 1 h after reaction.And its specific surface area S_BET,pore volume V_P,average pore size D_BJH and crystal size are 99.59 m²/g,0.271 cc/g,3.809 nm and 17.79 nm respectively.

Research on Thermal Oxidation/Vacuum Diffusion Treatment on Surface of Ti6Al4V Alloy and Its Effect on Wear Resistance

Zhou Yin, Wang Shuqi, Zhang Qiuyang, Wang Lan

2014, 35(2): 35-39,67. doi: 10.7513/j.issn.1004-7638.2014.02.007

Abstract(22) PDF(1)

Abstract:
Ti6Al4V alloy was processed with thermal oxidation at 800℃ for 1 h or at 900℃ for 15 min, then processed with vacuum diffusion at 850℃ for 20 h.At 25℃ and 400℃,dry sliding wear tests were performed for the alloy that underwent thermal oxidation at 900℃ for 15 min and vacuum diffusion at 850℃ for 20 h.A comparative study on microhardness distributions of the samples after vacuum diffusion and weight losses of the samples with or without processing was carried out.Microstructures and morphologies of the samples after oxidation or oxidation/diffusion and wear tests were analyzed by XRD, SEM,and EDS etc.The results show that titanium oxide forms on the surface after thermal oxidation, then TiO₂decomposes after vacuum diffusion.Between the surface oxide layer and the substrate,an oxygen diffusion layer generates and enhances their binding force,exhibiting a hardening effect.At the same time,some Al₃Ti appears.Under different load or temperature,the weight losses of the samples after oxidation/vacuum diffusion are much smaller than those of the samples without processing.Therefore,it can be concluded that the wear resistance of Ti6Al4V alloy after thermal oxidation at 900℃ for 15 min and vacuum diffusion at 850℃ for 20 h is significantly improved.

Changes of Microstructures and Cold Drawing Properties of V-N Microalloyed Tire Cord Steel

Wan Baoyi, Liu Hongyu, Zhou Peng, Liu Jianhua, Chen Xiaolong

2014, 35(2): 40-45. doi: 10.7513/j.issn.1004-7638.2014.02.008

Abstract(14) PDF(0)

Abstract:
To explore the possibility of replacing C with V and the effect of V and N on cementite during cold drawing process,traditional grade 70 tire cord steel was microalloyed with V and N.Tensile properties and torsional properties were measured for specimens at different cold drawing strains; the precipitation phases containing V and N were analyzed by a transmission electron microscope and energy dispersive spectrometer(TEM + EDS),saturation magnetization was measured by a vibrating sample magnetometer(VSM) to predict the variation rules of cementite dissolution.It is shown that with the addition of V,tensile strength of the cold drawn samples generally increases,elongation slightly declines,and the number of torsion decreases.With the addition of N,tensile strength of the cold drawn samples increases before decreases,elongation rises,and the number of torsion decreases.V partially dissolves in ferrite or cementite.N is soluble in ferrite when its content is low,the phases containing V start to precipitate in ferrite when N increases to 0.008 2%.With the increase of V and N,the cementite tends to stabilizes during the cold drawing process.The grade 80 tire cord steel can be replaced with(grade 70 + 0.086% V).

Analysis on the Feasibility of Co-production of Sulfuric Acid, Titanium Pigment and Iron and Steel in Panzhihua

Du Jianqiao, Xu Yuting

2014, 35(2): 46-50. doi: 10.7513/j.issn.1004-7638.2014.02.009

Abstract(46) PDF(0)

Abstract:
Aiming at utilizing wastes and by-products,the conception of 'co-production of sulfuric acid, titanium pigment and iron and steel' is put forward based on the existing iron & steel and titanium pigment industries in Panzhihua,and the feasibility of reutilizing by-products and wastes generated in the two production processes including waste acid,blast furnace slag,ironmaking and steelmaking afterheat, dilute titaniferous solution,copperas,and red slag is analyzed.It can be concluded that the co-production of sulfuric acid,titanium pigment and iron and steel is a good way to realize efficient utilization and clean production of iron,sulfur and titanium resources.It is suggested that a green industry demonstration base be established in Panzhihua.

Analysis on Electricity Consumption for Titanium Slag Smelting with Prereduced Concentrate Pellets

Han Kexi

2014, 35(2): 51-55. doi: 10.7513/j.issn.1004-7638.2014.02.010

Abstract(12) PDF(0)

Abstract:
Electricity consumption for titanium slag smelting with Panzhihua titanium concentrates is higher than that of the international advanced smelting technologies.However,it can be significantly reduced as prereduced Panzhihua titanium concentrates are used for the smelting.According to basic data obtained in industrial tests that have been carried out,combined with the main components of titanium concentrates and reducing agents,the chemical compositions of prereduced concentrate pellets with different metallization ratio are tested and calculated.On this basis,through thermodynamic calculation,electricity consumption for the smelting with the prereduced pellets charged into furnace at room temperature or 800℃ are calculated.The results show that prereduction of titanium concentrates is an effective way to reduce the electricity consumption of slag smelting.As the pellets with a metallization ratio of 60% instead of fine ores are charged into the furnace,the electricity consumption for smelting 1 metric ton of titanium slag is reduced from 2 800 kWh to 1 948.5 kWh.As they are charged at the temperature of 800℃,it can be further reduced to 1 523.1 kWh,which shows a good application prospect.

Empirical Prediction Model of the Incremental Strengthening of Ferrite /Pearlite Steels with Additions of Vanadium and Nitrogen

Robert J Glodowski

2014, 35(2): 56-61. doi: 10.7513/j.issn.1004-7638.2014.02.011

Abstract(24) PDF(0)

Abstract:
Several prediction models of V-N strengthening have been published and used over the course of many years of vanadium microalloying experience.The basis and origin of a proven strength model previously distributed is reviewed and explained.Inherent in the prediction accuracy of the model is the assumption of the amount of nitrogen actually available for VN precipitation.Various situations where the amount of nitrogen available can be significantly altered by the presence of other alloy elements,particularly Ti, Nb,and Al are discussed.Of these,the effect of the Al content(and prior processing history) seem to be most widely overlooked when evaluating and predicting the expected strengthening of the VN precipitate in polygonal ferrite.The possible interactions of Al and N that can affect nitrogen availability are reviewed, and the unintended effects of specification Al requirements are explained.

Study on the Moulding Process of Vanadium-bearing Titaniferous Magnetite Concentrate Pellets Containing Carbon

Li Junhan, Qiu Kehui, Yang Shaoli

2014, 35(2): 62-67. doi: 10.7513/j.issn.1004-7638.2014.02.012

Abstract(13) PDF(1)

Abstract:
By taking polyvinyl alcohol as binding agent and vanadium-bearing titaniferous magnetite concentrate and pulverized coal as raw materials,the influences of moisture,moulding pressure,the mass ratio of ore to coal and the amount of binding agent added on the metallization ratio of the pellets during direct reduction were studied through a series of orthogonal experiments and single factor experiments,and their influencing rules were analyzed.The results show that the affecting factors in order of descreasing importance are moisture,moulding pressure,the mass ratio of ore to coal and the amount of binding agent added.The optimized process parameters obtained are 9% of moisture,12 MPa of moulding pressure,100:22 of the mass ratio of ore to coal,0.4% of the amount of binding agent added,1 350℃ of temperature and 30min of reduction time.Under these conditions,the metallization ratio of the pellets can be up to 92.97%.

Research on Effect of Additives on Viscosity of Titanium-bearing Blast Furnace Slag of Chengde Steel

Cui Shiqiang, Lü Qing, Feng Shuai, Sun Yanqin, Chen Shujun, Li Fumin, Wan Xinyu, Kang Zepeng

2014, 35(2): 68-72. doi: 10.7513/j.issn.1004-7638.2014.02.013

Abstract(14) PDF(1)

Abstract:
According to current smelting conditions of Chengde Steel and by taking its BF slag as samples,effects of the addition of CaF₂,MnO,Li₂O,MgO or Cr₂O₃ to final slag on melting properties of the slag were studied with melt property tester RTW.The result shows that all of the additives are helpful to reduce the viscidity of slag.With the addition amount of CaF₂ of 0.5%~1.0%,MnO of 1.0%,MgO of 3%,Cr₂O₃ of 0.5%,or Li₂O of 1.0%,the best dilution effect is achieved.With an addition amount of 0.5%,the additives listed in order of decreasing effect are Li₂O,CaF₂,MgO,Cr₂O₃ and MnO.

Research on the Production of Low-phosphorus Steels with Semi-steel in Xichang Vanadium ＆ Steel

Qing Jiasheng

2014, 35(2): 73-77. doi: 10.7513/j.issn.1004-7638.2014.02.014

Abstract(24) PDF(1)

Abstract:
In order to meet the strict requirements of low- phosphorus steels,a suitable process was invented by Xichang Vanadium & Steel to smelt low-phosphorus high quality steels with semi-steel.By optimizing the oxygen lance of converter smelting process,selecting reasonable combined blowing and slag making schemes,and controlling end-point smelting temperature at about 1 620℃,the end-point phosphorus content was stably reduced from 0.013% to 0.006%,satisfying the requirements of high quality steels on dephosphorization.

Influence of Carbon Addition on Mineralogical Structures and Metallurgical Properties of Sinter Prepared with Fine-grained Hematite Concentrates

Liu Lina, Han Xiuli, Li Zhimin, Duan Shan

2014, 35(2): 78-81. doi: 10.7513/j.issn.1004-7638.2014.02.015

Abstract(19) PDF(0)

Abstract:
The mineralogical structures and metallurgical properties of sinter prepared with fine-grained hematite concentrates and different amount of carbon were systematically studied.The results show that where the proportion of Sijiaying iron ore is 100%,with the increase of carbon content,the mineralogical structures of the sinter homogenize gradually,and the contents of hematite and dicalcium silicate decrease.Where the proportion is 50%~90%,the drum index of sinter increases before decreases with the increase of carbon content; Where the proportion rises to 100%,the drum index of sinter increases.The low-temperature RDI and the reducibility of the sinter improve and decrease respectively with the increase of carbon content.The content of carbon should be increased with the increase of Sijiaying iron ore's proportion in raw materials for sintering.

Research on the Influence of Preheating on Combustion Characteristics of Pulverized Coal

Liu Ran, Wang Xingjuan, Liang Chunchao, Lü Qing, Zhang Shuhui, Du Linsen, Feng Shuai

2014, 35(2): 82-86. doi: 10.7513/j.issn.1004-7638.2014.02.016

Abstract(16) PDF(0)

Abstract:
By using two kinds of pulverized coal(namely,bitumite JM and anthracite FD) for BF injection from Handan Iron and Steel Co.,Ltd.as raw materials,the differential thermal analysis(DTA) of the pulverized coal preheated under different temperature was carried out and its combustion ratio determined.Experimental results show that the weight loss start temperatures of the two kinds of the pulverized coal are approximately the same at about 50℃.Without preheating,the weight loss finish temperature of JM is about 470℃,and FD about 640℃,while in the case of preheating at 300℃,the former decrease to about 460℃,and the latter to about 620℃.After preheating,the pulverized coal's surface structures have noticeably changed,and the increase of layered and pore structures results in improvement of combustion ratio.

Study on Reducing Dephosphorization of Hot Metal Containing Nb by CaC₂ Addition

Lu Jianfa, Zhao Zengwu, Xu Zhangyin

2014, 35(2): 87-91. doi: 10.7513/j.issn.1004-7638.2014.02.017

Abstract(10) PDF(0)

Abstract:
A study on reducing dephosphorization of Nb-bearing hot metal by adding CaC₂ was carried out with carbon contents in the hot metal of 0.5% to 1.9%,and hot metal's temperature of 1 550℃.Effects of the amount of dephosphorizing agent added and its adding way,the carbon content in the hot melt,and the crucible material on dephosphorization rate were investigated.To improve the dynamics condition of hot metal,a new adding way that the dephosphorization agent was added into the hot metal's interior through a steel pipe was adopted according to characteristics of CaC₂ decomposition.The experimental results show that as the carbon content in molten steel decreases to 0.5% from 1.9%,the dephosphorization rate increases to 41% from 25%,which indicates the dephosphorization rate decreases with the increase of carbon content in molten steel.The dephosphorization rate decreases when top feeding is used instead of embedded feeding.Since corrosion of Al₂O₃ refractory is found,MgO crucible instead of corundum crucible is suitable for reducing dephosphorizatin with CaC₂-CaF₂.The content of Nb in hot metal does not change during dephosphorization.

Experimental Research on RH Desulfurization Slag for Non-oriented Electrical Steel Smelting

Qin Zhe, Liao Jianjun, Lai Chaobin, Chou Shengtao

2014, 35(2): 92-96. doi: 10.7513/j.issn.1004-7638.2014.02.018

Abstract(10) PDF(0)

Abstract:
Experiments on desulfurization of molten steel using CaO-Al₂O₃-SiO₂-MgO based desulfurization slag was carried out in a 15 kg vacuum induction furnace.The effects of desulfurization slag basicity,MI, Al₂O₃ and CaF₂ on desulfurization of molten steel were studied.The results show that with the increase of basicity,MI,Al₂O₃ or CaF₂ in desulfurization slag,the desulfurization rate rises initially and then decreases.In addition,as the initial sulfur content is 0.009 33%~0.010 73%,the apparent desulphurization rate reaches(0.000 96~0.001 49)%/min within 4 min since the beginning of desulphurization,and the highest and average desulphurization efficiencies are 86.8% and 81.2% respectively.Furthermore,as w_(CaO)=58.15%,w_{(SiO_{2=4.85%,w(Al₂O₃)=25%,w_(MgO)=6%,w_(CaF₂)=6%,the desulfurization slag shows the best desulfurization effect,and the sulfur content in molten steel is 0.001 33%.}}

Simulation of Free Surface in a Continuous Casting Mould and Structural Optimization of a Submerged Entry Nozzle

Zhang Caijun, Liu Tao, Wang Ang, Gu Kejing, Zhu Liguang

2014, 35(2): 97-102. doi: 10.7513/j.issn.1004-7638.2014.02.019

Abstract(21) PDF(0)

Abstract:
By taking a continuous casting mould for rectangular slab production in a certain steel mill as the research subject,flow and flow fields of the free surface were systematically analyzed,flow conditions affected by different exit area ratio,immersion depth,and inclination of the submerged entry nozzle(SEN) were studied,and corresponding process parameters were optimized through numerical and physical simulation.Results show that for the rectangular slab with a 150 mm×440 mm section,the optimum exit area ratio,inner diameter and side opening angle of the SEN should be 2.42,30 mm and 25° respectively.

Study on Internal Quality Control of 20CrMnTiH Steel Strands

Wang Qingchun, Chen Tianming, Chen Liang, Yang Wenzhong

2014, 35(2): 103-107. doi: 10.7513/j.issn.1004-7638.2014.02.020

Abstract(13) PDF(1)

Abstract:
According to the requirements of 20CrMnTiH steel,effects of key parameters including casting peed,the mould's current intensity for electromagnetic stirring(EMS) and intensity of secondary cooling on internal quality of strands were studied.The results show that controlling the casting speed at 1.2~1.4 m/min is beneficial to the control of 20CrMnTiH strands' internal quality,and with current intensity for EMS of 380 A,the level of center porosity can be controlled within 1.0 and the index of carbon segregation not more than 1.08,and the equiaxed crystal ratio reaches 34.9%.Furthermore,center porosity and segregation can also be improved when weak secondary cooling is adopted.Based on these research findings,20CrMnTiH steel bars produced show good macrostructure and hardenability.

Study on the Behavior of Non-metallic Inclusions during Calcium Treatment of SPHC Steel

Zhang Tongbo, Li Jingshe, Chen Yongfeng, Sun Liyuan

2014, 35(2): 108-112,124. doi: 10.7513/j.issn.1004-7638.2014.02.021

Abstract(23) PDF(0)

Abstract:
The behavior of inclusions during calcium treatment of SPHC steel has been researched by systematic sampling during the process of refining and continuous casting.The results show that before Ca treatment,the Al₂O₃inclusions in steel mainly exist in triangular or irregular forms.After LF refining, most of inclusions are calcium aluminates which have been partly or completely modified.In the tundish, pure CaS forms and binds with calcium aluminates.As the continuous casting of steel proceeds,the proportion of sulfide inclusions increases and more CaS inclusions generate in strands which form annular structures wrapping modified calcium aluminates.

Effect of Thermal Deformation on Continuous Cooling Transformation Behaviors of V-N Microalloyed Steel

Zhao Baochun, Zhao Tan, Li Guiyan, Lu Qiang

2014, 35(2): 113-117. doi: 10.7513/j.issn.1004-7638.2014.02.022

Abstract(17) PDF(0)

Abstract:
Simulation tests were performed on a Gleeble-3800 thermo-mechanical simulator to study the transformation behaviors of V-N microalloyed steel without deformation or under multipass deformation conditions.The corresponding static and dynamic CCT diagrams of the tested steel were made by analyzing the dilatometric curves and microstructures combined with hardness measurement.Based on the observation of microstructures and precipitates by optical microscopy,SEM and TEM,the effects of deformation on microstructures were analyzed and the continuous cooling transformation behaviors of the tested steel were studied.The results show that the transformation of both ferrite and pearlite is promoted by application of strain and ferrite transformation occurs at a higher cooling velocity.At the same time,deformation promotes the precipitation process of vanadium carbonitride,which leads to ferrite transformation and microstructure refinement.Bainite is obtained at a wide range of cooling velocity regardless of the strain and the starting temperature of bainite transformation goes up at a higher cooling velocity.

Cause Analysis and Study on Hole Defects of Cold-rolled Sheets

Chen Liansheng, Yang Dong, Song Jinying, Tian Yaqiang, Zhao Yuan

2014, 35(2): 118-124. doi: 10.7513/j.issn.1004-7638.2014.02.023

Abstract(28) PDF(1)

Abstract:
The causes and influencing factors of hole defects emerging in cold rolling process were analyzed by means of SEM and EDS.The result shows that the causes of holes defects include inclusions(the main cause),impressed foreign matters,and roll abnormity etc.The hole defects caused by inclusions are characterized by lacerated or dimpled fracture,or crescent-shaped appearance,and show little size difference on both sides of steel plates,their formation is mainly connected with steelmaking process.The hole defects caused by impressed foreign matters are characterized by noticeable mechanical scratches or indentations,and those defects with smooth fracture have different sizes in the two sides of plates,their formation is mainly connected with hot rolling and cold rolling processes.The hole defects caused by roll abnormity are characterized by equidistant regular holes,and their formation is mainly connected with roll abrasion and aging.According to characteristics of different types of hole defects,corresponding improvement measures have been put forward.

2014, 35(2): 125-126.

Abstract(27) PDF(0)

Abstract:

2014 Vol. 35, No. 2