钢铁钒钛

Experimental Research on Leaching Calcification Clinker of Vanadium Slag by Sodium Bicarbonate for Preparation of V₂O₅

Fu Zibi, Zheng Shili, Sun Zhaohui

2015, 36(1): 1-6. doi: 10.7513/j.issn.1004-7638.2015.01.001

Abstract(25) PDF(1)

Abstract:
The preparation of V₂O₅ by the processes of sodium bicarbonate （NaHCO₃） for leaching and ammonium carbonate （（NH₄）₂CO₃） or ammonium bicarbonate （NH₄HCO₃） for vanadium precipitation was studied with vanadium slag clinker by calcified roasting as raw materials. The research mainly focused on the effects of leaching temperature,leaching time,leaching agent concentration and liquid-solid ratio on the vanadium leaching rate,and the conditions of leachate purification and vanadium precipitation were also investigated. The results show that more than 92% of leaching rate can be achieved under conditions as follows: leaching temperature 95 ℃,leaching time 120 min,concentration of Na HCO₃15.8% and liquid-solid ratio 3:1~4:1,and V₂O₅ which has the purity of 99.87% and satisfies the YB/T 5304-2011 standard can be obtained by adding sodium aluminate in the leachate for silicon removal with w_Al/w_Si= 0.6~0.8 and precipitating vanadium with （NH₄）₂CO₃ or NH₄HCO₃.

Research on Preparation of Synthetic Rutile with Panxi Ilmenite

Ye Endong, Cheng Xiaozhe, Miao Huijun, Zhang Jianbo, Wu Xuan

2015, 36(1): 7-15. doi: 10.7513/j.issn.1004-7638.2015.01.002

Abstract(27) PDF(2)

Abstract:
How to utilize the rich reserves of the low grade ilmenite containing high calcium and magnesium in Panxi area to prepare high quality titanium concentrates is the key to promote the development of titanium industry. Through the phase analysis of the compositions and structure of the ilmenite in Panxi area,a new method by using redox modification-hydrochloric acid leaching for preparing synthetic rutile was presented. In order to optimize the process,the condition tests had been conducted in the laboratory,and it helped to determine the key parameters. Based on these results,expanded tests for a 5 kt/a synthetic rutile had been researched. These experiments realized continuous and stable operation,and successfully obtained the products containing TiO₂% ≥90%,CaO + MgO≤1.0%,which could satisfy the needs of boiling chlorination. The wasted hydrochloric acid had been recycled by spray roasting technique in the leaching process,which realized a closed circulation and ensured the waste-free emission. Finally,a complete set of technology and operating system for producing synthetic rutile with Panxi ilmenite has been formed by using the technology of "fluidized oxidation- reduction- atmospheric leaching- waste acid recovery".

Study on Upgrading the Quality Grade of Ilmenite Concentrate

Liu Xibo, Chen Zhiqiang

2015, 36(1): 16-20,63. doi: 10.7513/j.issn.1004-7638.2015.01.003

Abstract(29) PDF(1)

Abstract:
The effects of oxidation temperature on the crystal structure of ball milling activated and unactivated ilmenite concentrate as well as upgrading the quality grade of ilmenite concentrate through acid leaching were investigated by oxidation treatment and acid leaching. The results indicate that,after oxidation at 750~800 ℃,the new phases of Fe₂Ti₃O₉,Fe₂O₃ and rutile TiO₂ appear in the ilmenite concentrate with comparatively sufficient phase transition,and the phase transition starts at a lower temperature and the conversion rate is higher for the milling ilmenite concentrate. After annealing at 800 ℃ and acid leaching at 105 ℃ for the milling ilmenite concentrate,the content of Ca O and Mg O separately decreases to 0.089% and 0.888% respectively with 88.7% and 51.8% of removal rate,and the content of TiO₂ increases from 44.12% to 53.64%,which shows a significant improvement for the quality grade of ilmenite concentrate.

Study on Molten Salt Electrolysis of Consumable Anode TiC_xO_y

Gong Lixia

2015, 36(1): 21-25. doi: 10.7513/j.issn.1004-7638.2015.01.004

Abstract(31) PDF(1)

Abstract:
Electrochemical dissolution behaviors of self-made consumable anode TiC_xO_y （x ≈ 0.50,y ≈0.50） as well as cathode in simple chloride （NaCl-KCl） molten salt system and NaCl-KCl-TiClx molten salt system containing 3.5% low valence titanium ion were researched. The results indicate that the consumable anode TiC_xO_y can normally dissolve in both of the molten salt systems mentioned above,but few products deposit on the cathode in NaCl-KCl molten salt system. Cathode products are favorably obtained in NaCl-KCl-TiClx molten salt system with anode current efficiency more than 50%. Dissolving rate of anode decreases to 50% in NaCl-KCl-TiClx molten salt system from 80% in NaCl-KCl system.

Preparation and Photodegradation of Photocatalytic Functional Fe₂O₃/TiO₂ Ceramics

Li Rong, Jia Yuefa, Zhen Qiang, Bu Naijing, Wu Jun

2015, 36(1): 26-31. doi: 10.7513/j.issn.1004-7638.2015.01.005

Abstract(28) PDF(1)

Abstract:
Using iron nitrate nonahydrate （Fe（NO₃）₃·9H₂O） and titanium sulfate （Ti（SO₄）₂） as raw materials,Fe₂O₃/ TiO₂ mixed powders were synthesized by co-precipitation method. The green cylinders were formed under axial-pressure and sintered at high temperature to obtain the Fe₂O₃/TiO₂ ceramics.Phase and microstructure of Fe₂O₃/ TiO₂ porous ceramics were analyzed by XRD and SEM. The photocatalytic and recyclable performances of the ceramics material in the degradation of methyl blue （MB: 25 mg/L） were studied. The results indicate that after the first time of catalysis about 80% and 94% of MB is degraded with Fe₂O₃/ TiO₂ ceramics respectively under the ultraviolet and visible （UV/vis） light,after three times of recycles the maximum degradation rate of MB by Fe₂O₃/ TiO₂ ceramics only reduces by 16% and 17% under the ultraviolet and UV/Vis light,respectively. The Fe₂O₃/ TiO₂ porous ceramics shows a good photocatalytic and recyclable performance,which is suggested to be a promising new photocatalysts widely used in the pollutant water treatment.

High Temperature Deformation Behavior and Constitutive Equation of Pure Titanium for Finish rolling

Ren Wanbo, Li Jun, Chen Shanhua, Yu Hui

2015, 36(1): 32-37. doi: 10.7513/j.issn.1004-7638.2015.01.006

Abstract(24) PDF(2)

Abstract:
In order to study the effect of high temperature deformation parameters on the high temperature deformation behaviors of hot rolled pure titanium tape in finish rolling process,Gleeble -3800 thermal simulation machine was employed to the high temperature compressive test of pure titanium. According to the finishing process parameters for hot rolling pure titanium,hot compression temperature was set at the range of 700~800℃,strain rate was determined at the range of 0.01~10 s^-1 and the deformation degree was 80%. The results show that the flow stress of pure titanium decreases with the increasing deformation temperature and increases with the increasing strain rate,dynamic recovery occurs at 700~775 ℃ and dynamic recrystallization happens only under the condition of 800 ℃ and less than 1 s^-1 of strain rate. Based on the hyperbolic sine Arrhenius model,the constitutive equation of pure titanium was established by use of linear regression method,which provided a theoretical basis for the numerical simulation and thermal processing of pure titanium.

Exploration about the Production of HRB400 Hot Rolled Rebar by Nitrided Ferrotitanium Microalloying Technology

Wang Anren, Zhang Qingchun, Wang Guofeng, Guo Senlin, Hou Wei

2015, 36(1): 38-42. doi: 10.7513/j.issn.1004-7638.2015.01.007

Abstract(39) PDF(1)

Abstract:
Strengthening mechanism for rebar with nitrided ferrotitanium is studied by optical microscopy,scanning electron microscopy and transmission electron microscopy,with HRB335 rebar produced by a domestic steel mill and the rebar containing a certain amount of nitrided ferrotitanium based on HRB335 as raw materials,respectively. Experimental results demonstrate that rebar’s strength and ductility are both enhanced as the nucleation of ferrite grain is promoted and ferrite grain is refined by the precipitation of numerous TiN particles produced in the process of solidification. Precipitates obtained by extraction replica method mainly contain a few composite oxides and Ti（C,N） whose size is usually less than 10 nm with multi-wide distribution. So it is quite feasible to use nitrided ferrotitanium as an alloy element to produce HRB400 hot rolled rebar.

Influence of Vanadium on Microstructure and Properties of High Nitrogen 20MnSi Steel

Yang Jichun, Zhang Jian, Li Hongwei, Zhou Li

2015, 36(1): 43-47. doi: 10.7513/j.issn.1004-7638.2015.01.008

Abstract(23) PDF(1)

Abstract:
The effect of vanadium on the microstructure and mechanical properties of 20 MnSi thread steel with high content of nitrogen was studied,and the fracture morphology of the tested samples was analyzed by scanning electron microscopy. The results show that the grain size of 20MnSi thread steel decreases from 8.6 μm to 1.9 μm with increasing content of vanadium but the precipitates of cementite are not flat and straight. Mechanical properties of the thread steel containing 0.039% vanadium are significantly improved with yield strength reaching 944 MPa,1 100 MPa of tensile strength,26% of elongation and yield ratio 0.85. The brittle zone of 20MnSi thread steel is found to transform into plastic zone with increasing content of vanadium and disappear with 0.047% vanadium.

Causes and Countermeasures of Scaling in Ammonia Stripper for Ammonium Vanadate Precipitating Waste Water

Teng Xiaohui

2015, 36(1): 48-51. doi: 10.7513/j.issn.1004-7638.2015.01.009

Abstract(16) PDF(1)

Abstract:
The reasons of scaling in the ammonia stripper for the ammonia and nitrogen removal from the ammonium vanadate precipitating waste water were discussed in this paper. The main cause was found to be the formed calcium and magnesium scaling in the ammonia stripper by the complex chemical reactions between the calcium & magnesium ions and carbonate,hydroxide,silicate ions under high temperature and alkaline conditions. The countermeasures for solving scaling were also proposed as follows: ①Adding the scale inhibitor KL101 to vanadium precipitation wastewater with weight ratio of 0.02%; ②Regularly cleaning the pipelines,heat exchangers and Pall ring in the ammonia stripper. After the implementation of the measures mentioned above,the operating period of the ammonia stripper increased from less than 7 days to more than 40 days,which achieved long-term,safe and stable continuous operation with less than 30 mg /L NH₃-N in the waste water after ammonia removal and satisfying the discharge standard.

The Experimental Study on Direct Reduction of Shaft Furnace Based Gas of Vanadium Titanium Magnetite

Shi Xuefeng, Xu Hongjun, Zhang Yingyi, Wan Xinyu, Cao Xiao'en

2015, 36(1): 52-56. doi: 10.7513/j.issn.1004-7638.2015.01.010

Abstract(25) PDF(12)

Abstract:
The gas based reduction behavior and the influence factors of vanadium titano magnetite were studied. The influence of reduction temperature,reduction time,reduction atmosphere and gas flow rate on percent of reduction and metallization rate were analyzed. The result shows that the percent of reduction is 96.72%,the metallization rate is 92.05% when temperature is 1 000 ℃,time is 2 h,atmosphere is 21%CO+55%H₂+24%N₂,gas flow rate is 13.26 L/min. The Fe of iron oxide of vanadium titano magnetite can be reduced,and realize efficient enrichment of Fe by using gas based shaft furnace direct reaction.

Studies on Kinetics of Hydrogen Reduction of Different Diameter Ironsand Oxidized Pellets Containing Titanium

Li Yongqi, Guo Hanjie, Li Lin

2015, 36(1): 57-63. doi: 10.7513/j.issn.1004-7638.2015.01.011

Abstract(8) PDF(1)

Abstract:
In this paper,the kinetic mechanism of reducing different sizes of Indonesia ironsand oxidized pellets by hydrogen was studied by means of gravimetrie method. The research mainly focuses on the kinetics. The results showed that the different reduction mechanism presents at different temperature. The restrictive step was composed of two different stages when reduction temperature was below 900 ℃,that is,the reduction begun with chemical reaction,and then was controlled by chemical reaction and intraparticle diffusion. When the temperature exceeds 900 ℃,The reduction mechanism was composed of three stages,that is,beginning with chemical reaction,followed by mixed-control of chemical reaction and intraparticle diffusion,and finally ended by intraparticle diffusion. At any reduction temperature,small oxidized pellets show a faster reaction speed at chemical reaction restrictive step,and have a smaller reaction resistance at intraparticle diffusion restrictive step.

Research on Desulfurization Capability of Medium ＆Low-titanium BF Slag

Zhang Xusheng, Lü Qing, Liu Xiaojie, Qie Yana

2015, 36(1): 64-67,91. doi: 10.7513/j.issn.1004-7638.2015.01.012

Abstract(4) PDF(1)

Abstract:
The desulfurization capability of medium-titanium and low-titanium BF slag in Xuangang was investigated. The results show that basicity,Ti,Mg and Al have important effect on the desulfurization of slag in the CaO-Al₂O₃-SiO₂-MgO-TiO₂ slag system. With basicity increasing,desulfurization capability of slag increases. For a certain basicity,increasing the content of TiO₂ will bring negative effect on desulfurization. When the basicity of slag is 1.1,the suitable slag composition with near 10.00% of MgO and ~12.00%, of Al₂O₃ is beneficial to desulfurization. Increasing MgO content and decreasing Al₂O₃ content appropriately are good for desulfurization as Ti content increases. Controlling the slag parameters reasonably is important for reducing the sulfur content of cast iron and improving desulfurization capability of slag.

Effect of FeO on Properties of Low Titanium Sinters

Lü Qing, Zhang Xusheng, Liu Xiaojie, Qie Yana

2015, 36(1): 68-72. doi: 10.7513/j.issn.1004-7638.2015.01.013

Abstract(17) PDF(1)

Abstract:
According to sintering proportioning of Xuangang,the influence of FeO on properties of sinters containing titanium was investigated by mini- sintering test and sinter pot test. The results show that FeO has a great effect on the quality of sinter in the process of sintering. With the content of FeO increasing,the assimilation temperature of sinter decrease,the binding phase strength rise and the liquid phase fluidity rise first and then decrease. The sintering cup test verified that increasing FeOcontent led to high tumbler index,which agreed with the effect of FeO on the basic characteristics of the sinter. The optimal content of FeO in the mixed ore was 14.43%~16.19%. The FeO content in the sinter was reasonablly controlled and the law of FeO on sinter was used,which were important for comprehensive utilization of mineral resources and optimization ore proportioning.

Microstructure and Properties of Vanadium-bearing DP980 Steels Processed with Continuous Galvanizing Line Simulations

Gong Yu, Liang Xiaojun, Hua Mingjian, A. J. DeArdo

2015, 36(1): 73-76. doi: 10.7513/j.issn.1004-7638.2015.01.014

Abstract(13) PDF(1)

Abstract:
A study is being conducted of additions of the microalloying elements Nb,V and V-N to a low carbon,high-strength （980 grade） Dual-Phase steel that was processed using a CGL simulation. In this study,compositions with a common base but containing various additions of V or Nb with or without high N were designed and subjected to Gleeble simulations of different galvanizing （GI）,galvannealing （GA） and super cooling processing. These experiments were supplemented with additional heat treatments performed using a quartz filament furnace. The results revealed that the phase balance （martensite-bainite-ferrite）was strongly influenced by the different microalloying additions,while the strengths of each phase were somewhat less affected. UTS levels of 1 100 MPa,along with good levels of ductility and work hardening,were measured in steels containing less than 0.1% C and 1.75% Mn. The results of this program will be presented and discussed.

Research on Suitable Rail Selection Based on Notable Damage of Nucleus Flaw

Yuan Jun, Deng Jianhui, Gao Hong, Zhou Yu, Yue Zheng

2015, 36(1): 77-80. doi: 10.7513/j.issn.1004-7638.2015.01.015

Abstract(11) PDF(1)

Abstract:
The rail damage characteristic and cause have been researched regarding the rail line with notable damage of nucleus flaw. Paving trial of the hot- rolled U76 CrRe and U75 V rail,and the heat treated U75 V and PG4 rail have been carried out in the section with notable damage of nucleus flaw in Cheng Kun line and Long Hai line. The results from research and trial indicates that the heat treated rails have better fatigue and nucleus flaw resistance than hot rolled rails. For the application in the line with notable damage of nucleus flaw,the heat treated rail has been suggested that rather than the hot- rolled rail.

Cause Analysis on Strength Fluctuation of High-strength Steel with Mo-Ti

Liang Wen, Wu Run, Liu Zhiyong, Tao Wenzhe, Chen Jiqing, Tan Jiamei

2015, 36(1): 81-84. doi: 10.7513/j.issn.1004-7638.2015.01.016

Abstract(12) PDF(1)

Abstract:
The cause of strength fluctuation of Mo-Ti microalloyed high-strength steel was investigated by metallography observation and energy spectrum analysis. The results showed that strength fluctuation was mainly caused by higher coiling temperature and the inhomogeneous temperature profile through width direction. Thepeak precipitation temperature of the high-strength steel with 0.12Ti-0.10Mo（%） was about 570 ℃. Mo could promote a large amount of second phase （Mo_xTi_1-x）（C_yN_1-y） precipitates in Ti microalloyedsteel,and the dispersive and nano-size second phase could yield strong precipitation strengthening effect. By lowering the coiling temperature and adopting the edge-masking technology in the laminar cooling line,the high-strength steel with tensile strength more than 800 MPa and homogeneous strength was obtained.

Research on Non-metallic Inclusions Behavior in Continuous Casting Square Billet of Q235 Steel

Sun Ligen, Ren Yingqiang, Liu Yang, Zhu Liguang, Liu Zengxun

2015, 36(1): 85-91. doi: 10.7513/j.issn.1004-7638.2015.01.017

Abstract(17) PDF(2)

Abstract:
Based on the inclusion tracer method,all aspects of the converter-continuous casting process adopted by iron and steel enterprises during produced Q235B steel production had been researched systematically. The results show that strand has high inclusion content level and strong reoxidation. Microscopic inclusions mainly consist of SiO₂-Mn O-MnS,SiO₂-Mn O-MoO₃ composite and no Ce and La has been measured,however,tracers of Ce,La,K,Na have been found in most of macro inclusion,which implies that macro inclusions mainly come from the tundish covering flux,mould flux and ladle slag. For reducing the big inclusion content which has the worst effect on the steel quality,the structure of the tundish and the submerged entry nozzle should be optimized,the casting technology should be more stable,at the same time the met allurgical properties of the supplementary material should be optimized to fit for the current casting.

Research on the Evolution of Inclusions in LX72A Steel Produced by LD-LF-CC Process

Xin Caiping, Yue Feng, Tian Luolin, Wu Qifan

2015, 36(1): 92-97. doi: 10.7513/j.issn.1004-7638.2015.01.018

Abstract(6) PDF(1)

Abstract:
By using the thermodynamic calculation,systematic sampling from BOF,LF,tundish,casting billets and the wire rod combined with SEM analysis,the type and amount of inclusions as well astotal oxygen content and the nitrogen content in LX72 A steel which produced by LD-LF-CC process have been investigated and measured at various production steps. The results show that the type of inclusions at the end of BOF is mainly Al₂O₃-SiO₂-MnO. After LF treatment,the inclusions translates into spherical Al₂O₃-SiO₂-CaO-MgO particles which have a low melting point and easily floating up. At the stage of wire rod production the inclusions evolves into Al₂O₃-SiO₂-CaO-MgO system. The amount of inclusions in tundish and casting billets decrease dramatically,indicating that changing basicity benefits to inclusions modification. The total oxygen content was 25×10^-6 and the nitrogen content was 40×10^-6 in the wire rod,which meets the requirements for steel cord.

Mathematical Simulation and Application of Flow Field of Molten Steel for Five-strand Symmetrical Tundish

Yang Chunyu, Sun Yanhui, Zhang Xichao, Xu Rui, Ge Liang, Wang Chengyi

2015, 36(1): 98-102. doi: 10.7513/j.issn.1004-7638.2015.01.019

Abstract(16) PDF(1)

Abstract:
In view of excessive non-metallic inclusion content in a five-strands symmetric casting 150 mm×150 mm bloom,the effect of different flow control devices on flow field of liquid in tundish has been studied by means of numerical simulation in order to get optimum baffle. The results reveal the prototype tundish presents the problems such as short average residence time,large dead zone and erosion in the tundish by molten steel. When using the optimum new U-type baffle,average residence time increased by 257.11 s and dead area volume fraction decreased by 27.31%,the standard deviation of average residence time of each nozzle was smaller. Field experiment results shows that T[O]in liquid in tundish decreases by 45.81% and the amount of large inclusions decreases considerably.

Effect of Wollastonite on Crystallization Properties of Mould Powder

Han Xiuli, Zhang Han, Liu Lei, Pan Miaomiao, Liu Lina

2015, 36(1): 103-108. doi: 10.7513/j.issn.1004-7638.2015.01.020

Abstract(11) PDF(1)

Abstract:
The effect of wollastonite on crystallization properties and crystallization phase of mould powder made of cement clinker and industrial mineral raw materials in laboratory had been studied through process mineralogy. The results show that the crystallization temperature decreases with the content of wollastonite increasing at the same cooling speed. The critical cooling rate decreases by 2 ℃/s when increasing 2% wollastonite. And increasing wollastonite content leads to long incubation time of crystallization which can improve the lubrication degree of slab. When the content of wollastonite ranges from 11% to 19%,the crystallization ratio of the resulted mould flux is more than 80% where the main minerals in flux film are cuspidine and wollastonite. The contents of the two kinds of crystallization phase are similar when wollastonite is less than 15%. However,when the content of wollastonite is above 17%,the crystallization phase consists of more wollastonite and less cuspidine. At the same time,the viscosity increase somewhat but the heat flux increase obviously which is unbeneficial to control heat transfer. To achieve the balance of heat transfer and lubrication,the suggested content of wollastonite is 15% or less.

Analysis on Thermal History of Slab through BP-HR Process

Dang Aiguo, Cui Juan, Li Yongchao, Feng Yan

2015, 36(1): 109-113. doi: 10.7513/j.issn.1004-7638.2015.01.021

Abstract(11) PDF(1)

Abstract:
The temperature evolution through breakdowning,reheating,stack cooling and water descaling for bloom with dimension of 325×280 mm² had been studied by means of numerical simulation in this paper. The calculations show that the temperature at corner of transferred bar after 9-passes breakdowning to 160×160 mm² billet is 990 ℃,while it decreases down to 1 012 ℃ for middle section of billet surface.50 minutes reheating can bring the cold charged billet to the temperature of 1 000 ℃,while 40 min utes is sufficient to reheat the hot charged billet up to 1 060 ℃ required for rolling. For the slab after stack cooling for 48 hs,center temperature of slab on the top of stackcooled down to about 20 ℃,while for the slab at middle of stackthat temperature was about 80 ℃. Cooling rate of slab locating from the top to down of stack gradually slows down varing from 8.3 to 15.3 ℃/h and average value is 10.44 ℃/h. Regarding hot rolled billet after descaling section,corner temperature was about 1 053 ℃,and edge center temperature approximates 1 055 ℃. Temperature change through descaling is about 15 ℃.

Analysis on Surface Defects at the Hot and Cold Rolled Strip Edges

Wang Enrui, Lin Zhangguo, Gu Fenglong, Jia Gengwei, Wang Lianxuan, Cheng Di

2015, 36(1): 114-119. doi: 10.7513/j.issn.1004-7638.2015.01.022

Abstract(14) PDF(1)

Abstract:
Surface defects occurring in strip and their formation mechanism had been investigated. By the means of key process data analysis and SEM observation,it was found that the morphologies of the defects are similar,but the causes are different. The structure characteristic of layered defects induced by exogenous inclusions is that many particles containing F、Na、Mg、Si and other elements combined with iron oxide/inclusion co-exist layer distribute along the rolling direction continuously. The layered defects of thin gauge cold rolled strip possess a smooth interlayer,which is caused by the improper process parameters adoption. Scratch characteristic is significant near the silver defects,and no oxidant or inclusions are found. This findings provide a new way for the analysis of strip surface defects.

Cause Analysis on Surface Upwarping and Edge Defects of Hot Rolled Strip

Ding Meiliang, Guan Jianhui, Sun Lin

2015, 36(1): 120-124. doi: 10.7513/j.issn.1004-7638.2015.01.023

Abstract(44) PDF(7)

Abstract:
In order to improve quality of strip steel,the microstructure and chemical composition of surface upwarping and edge defects regions were investigated by OM,SEM,and EDS,and the causes were analyzed.The results show that,there are iron oxides,secondary oxidation and composition of mold flux in surface upwarping regions,which are expected to come from slag entrapment in mold,surface cracks on continuous casting billet,surface scratches on hot strip,flanging in rolling processes. There are iron oxide,secondary oxidation,calcium aluminates and Mn S in edge defects,the reason may be attributed to cracks on continuous casting billet and internal inclusion in steelmaking process. The key to obtain high quality of hot rolled strip are improving the quality of continuous casting billet and controlling defect in hot rolling process.

2015, 36(1): 125-126.

Abstract(23) PDF(1)

Abstract:

2015 Vol. 36, No. 1