钢铁钒钛

Effect of Coiling Temperature on Evolution of Microstructure and Texture During Annealing

Zheng Zhiwang, Chen Jie, Zhou Dan

2007, 28(1): 1-8.

Abstract(20) PDF(1)

Abstract:
According to the technical process of modified Sindzmir continuous hot-dip galvanizing lines,Gleeble-1500 annealing simulation were conducted to systematically study the effect of coiling temperature on the evolution of microstructure and recrystallization textures as well as the recrystallization temperature of a Ti-IF steel during annealing,and the means of optical microscopy,X-ray texture measurement and hardness testing were employed in the study.The steel was industrially hot rolled with different coiling temperatures and cold rolled.The results showed that the full recrystallization temperature decreases as the coiling temperature is increased.When the annealing temperature is below 880℃,the annealing temperature has little influence on the recrystallization grain size,the grain size is above ASTM grade 11.0 for low temperature coiled steel and about ASTM grade 10.5 for high temperature coiled steel.When the annealing temperature is risen to 920℃, the grain remarkably coarsens.Strong {223}<110> and {114}<110> texture components were found after annealing.Their intensity is little affected by coiling temperature and annealing process yet the intensity of {111} recrystallization texture tends to increase when the annealing temperature is increased,especially at higher annealing temperature.When the annealing temperature is further increased to 920℃,the intensity of {111} recrystallization texture increases obviously.

Study on Inclusion of Tire Cord Steel 72A During Refining Period

Wang Haitao, Xu Zhongbo, Wang Yong, Zhang Jun, Zhang Yuan, Xu Xiaodong, Luo Bogang

2007, 28(1): 9-12,17.

Abstract(22) PDF(1)

Abstract:
The [Al]_S and T[O] content of 72A and the composition and photos of the inclusions during LFVD refining period in Capital Steel were systematically analyzed.The results show that the[Al]_S content increases sharply between the end of LF and beginning of VD,after VD most of the inclusions are in the high melting temperature area.It is concluded that the aluminum in alloy and Si-Ca wire feeding cause the increase of[Al]_S,the high CaO and low SiO₂ content are the main reason of inclusions being in high melting temperature.The improving measures are put forward which include reduction the Ca content of deoxidizes, cancel wire feeding and decrease the basicity of refining slag.

Numerical Simulation of Optimizing SEN Structure for Wide Slab Caster Mold

Shen Qiaozhen, Zhu Bilian

2007, 28(1): 13-17.

Abstract(24) PDF(1)

Abstract:
The fluid flow in a wide slab continuous caster mold was simulated by a three-dimensional model set up using the commercial software PHOENICS.The effects of the nozzle bottom construction,outlet angle and immersion depth of SEN (submerged entry nozzle) on the wave amplitude of the fluid near the interface was tested,and the influence of fluid flow on the impetus to narrow side of mold and the level of vortex center was also tested.So the reasonable SEN structure was put forward for the wide slab caster mold,this could be an available basis for optimum fluid flow and SEN design of a wide slab continuous caster mold.

Dynamic Recrystallization Behavior of 34CrMoV Steel

Wang Xiaofeng, Wang Lei

2007, 28(1): 18-21.

Abstract(27) PDF(1)

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The effect of process parameters on dynamic recrystallization of 34CrMoV steel was carried out by isothermal compression testing using Gleeble-1500 thermal simulator.The results showed that the flow stress decreased with the increase of temperature while increased with the increase of strain rate.The dynamic recrystallization rate increased with the decreasing of strain rate and the increasing of strain and deformation temperature,and the austenite grains were fined.

Study on Extraction of Vanadium from Acid Leaching Solution of Stone Coal with Ion Exchange Resin

Wang Bin

2007, 28(1): 22-25,52.

Abstract(22) PDF(1)

Abstract:
Several kinds of resins are tested in the ion exchange experiment to study their abilities of absorption and desorption to the vanadium from acid leaching solution of stone coal.The results show that ion exchange is an excellent method for removing the impurities and concentrating the vanadium from the acid leaching solution of stone coal.Absorption time and pH value of the solution would affect the absorption efficiency of resin for vanadium,and the kinds of desorption agent and desorbing time would affect the desorption efficiency either. The absorptivity of 1^# resin can get 99% of its maximum amount while the desorption can reach 95% with suitable desorption agent in 4h.The purity of V₂O₅ deposited from the desorption solution after been decontaminated and bated can get over 99%.

In Situ Synthesizing of Fe-V（C,N）Composite

Yang Tinggui, Wang Yisan, Cheng Fengjun

2007, 28(1): 26-30.

Abstract(22) PDF(1)

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A reinforced iron matrix composite with in situ V(C,N) particulates was synthesized by powder metallurgical technique.The microstructure and phase of the composite were tested with SEM and XRD.It was found that the stability of σ-(FeV) was reduced due to the presence of the activated atoms of carbon and nitrogen,and the σ-Fe consisting of V(C,N) particles well-distributed in the matrix were synthesized at 1200℃under the nitrogen condition.The growing up of in situ V(C,N) particulates were inhibited presumably due to the effect of nitrogen in reducing solubility of the particles in the matrix.The volume fraction of V(C,N) particles was up to 50% with particle sizes in the range 0.5~3μm.The composite possesses great wear-resistance under the condition of dry slipping with a heavy load.

Effect of Vanadium on Property of Spraying Alloy Material

Lin Jiandong, Huang Ping, He Fan, Yu Guangfu, Ran Rongping

2007, 28(1): 42-47.

Abstract(11) PDF(1)

Abstract:
In order to improve the wearablility and spalling resistance of Fe60E and Ni60A spraying alloy layer, two new spraying alloys named Fe60EV and Ni60AV are developed by add 1.5%~1.8% V into Fe60E and Ni60A spraying alloy.The hardness,wearablility and spalling resistance of the new spraying alloy layers are tested in laboratory.The results show the properties of Fe60EV and Ni60AV spraying layers are better than that of Fe60E and Ni60A spraying layers,that is the hardness is higher and the wearablility and spalling resistance are improved obviously.The Fe60EV and Ni60AV as well as Fe60E and Ni60A are sprayed on the backing block of an industrial hot rolled coiler respectively.The practical results show the service life of the backing block sprayed Fe60EV and Ni60AV alloy layers prolongs over 30% than that of sprayed Fe60E and Ni60A spraying alloy layers respectively.

Control Technique of Inclusions for Rail Steel with High Cleanliness

Ceng Jianhua

2007, 28(1): 48-52.

Abstract(21) PDF(1)

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In order to control the non-metallic inclusions in producing of rail steel with high cleanliness for 350 km/h,the research in control technique of non-metallic inclusions was carried out systematically.The removal ratio of non-metallic inclusions increased remarkably by adopting proper blowing argon mode at ladle bottom and optimum composition of ladle slag,and the T[O] reduced about 40%.The shape and composition of the inclusion was controlled effectively by modifying sulphide.After applied the control techniques in the production of rail steel with high cleanliness for 350km/h,the T[O]in steel rail reduced to 10.17×10^-6,A type inclusion ≤ 2.0 grade,B,C and D type inclusion ≤ 1.0 grade,which could meet the requirement of technical indexes for high speed steel rail,and made Panzhihua Iron and Steel Company become the first enterprise at domestic could produce rail steel with high cleanliness for 350 km/h in mass scale.

Influence Factor of Sulphur Yield for Resulphurized Free-cutting Steel

Jiang Guanghui, Gu Longjian, Shi Zhe, Chen Yong, Ceng Jianhua, Wu Guorong

2007, 28(1): 53-55,72.

Abstract(19) PDF(1)

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With the aim of reducing the fluctuation of sulphur content in resulphurized free-cutting steel for the change of yield during smelting,the factors of influence sulphur yield in resulphuried free-cutting steel was discussed based on the thermodynamic analysis.A series of experiment was carried out to investigate the effect of basicity on the sulfur yield.The relationship of slag basicity and sulphur yield was obtained by use of numerical regression method,it could be a reference for controlling sulphur yield during production of resulphurized free-cutting steel.

Effects of Alkali Metal on BF Smelting with Vanadic Titanomagnetite and Control Measures

Jiang Sheng, Yang Dongmei

2007, 28(1): 56-60.

Abstract(31) PDF(1)

Abstract:
The enrichment by circulating of alkali metal in BF (blast furnace) smelting with vanadic titanomagnetite is analyzed.The effect of alkali metal on burden properties and BF smelting is researched,the potential hazard of alkali metal is discussed and the control measures are put forward.It is concluded that the alkaline loads of BF in PZH Steel is high,while the slag bearing TiO₂ has high capacity of alkalis discharge,so the alkaline hazard is not come up yet.The coke quality is worsening in recent years since the attack of alkalis,it should be pay attention.Through reasonable proportioning of mixed coal and passivating treatment of coke,the CRI,CSR and the alkaline corrosion resistance of coke could be improved.

Research on Behavior of Microwave Absorbing and Reduction Effect of Yunnan Ilmenite in Microwave Field

Lei Ying, Peng Jinhui, Huang Mengyang, Huang Ming, Zhang Shimin, Zhang Libo

2007, 28(1): 31-34,52.

Abstract(9) PDF(1)

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The absorbing microwave characteristics of Yunnan ilmenite is measured,and the spectrum chart indicates Yunnan ilmenite has good absorbing microwave characteristic.According to above result,a new technique of reducing Yunnan ilmenite by microwave radiation is put forward.Through measure the absorbing microwave characteristic of mixed ilmenite and coke,the optimal coke ratio in the mixture is ascertained.The effect of process conditions on TiO₂ grade after reduced is researched,which include the ratio of coke and complex additive in the mixture,reduction temperature and reduction time etc.The optimal process parameters of reducing Yunnan ilmenite by microwave radiation are:reduction temperature 1 150℃,reduction time 1.5 h, the ratio of complex additive and mixed carbon respectively 3% and 15%.In this condition,the TiO₂ grade in reduced ilmenite is 50.34%.

Research on Dynamic Soft Reduction Technologies for Bloom Continuous Casting of Heavy Rail

Chen Yong, Yuan Hongwei, Yang Subo, Chen Lu:Ying

2007, 28(1): 35-41.

Abstract(25) PDF(1)

Abstract:
With the aim of reducing the center looseness and central segregation of heavy rail steel bloom by enhancing the metallurgical results of soft reduction (SR) employed in continuous bloom caster,a series of experiments for optimizing the process parameters of soft reduction is carried out.The influence of the soft reduction parameters on the internal quality of heavy rail steel bloom is analyzed,which include center looseness and central segregation etc.On the basis,the dynamic soft reduction scheme most suitable for heavy rail steel is developed,which improves the internal quality of heavy rail steel bloom obviously.The practical operation shows that the ratio of center looseness ≤ 1.0 is increased from 28% to 99.91%,central segregation and central shrinkage cavity are all ≤ 1.0 whose ratio are 40.91% and 92.05% respectively before optimization,and central segregation index of carbon is decreased from 1.17 to 1.05.Internal quality and mechanical performance of the rails produced from continuously cast blooms have met the requirement of 350 km/h high-speed tracks.

Study on Surfacing Technologies of Wrapper Rolls and Deep Camber Rolls Used for Rolling Mill

Ma Yaodong, Fu Dingmei, Shen Fenggang, Liu Jingfeng

2007, 28(1): 61-67,72.

Abstract(20) PDF(1)

Abstract:
Adopting YJ356-S and YJ358-S welding wires developed by Welding Research Institute of MCC, the wrapper rolls and deep camber rolls used for rolling mill are repaired,and the surfacing technologies are particularly researched.The surfacing microstructures of wrapper rolls are tempering martensite+bainite+sorbite +carbides,and that of deep camber rolls are tempering martensite+dispersion carbides.After tempering treatment,the hardness of the surfacing layer of wrapper rolls reaches 59.9HRC and that of deep camber rolls reaches 63.1HRC.The result of wearing test shows that the relative wear-resisting coefficients of YJ356-S and YJ358-S surfacing metals are 0.105 and 0.121 respectively,both have excellent wear resistances.In addition,the electromagnetic stirring added in surfacing molten pool is help to increase the hardness and reduce the hardness difference of surfacing layer,it also improves the wear resistance of surfacing materials.

Study on Batch Annealing Process of Ti-IF Steel Cold Rolled Sheet

Zuo Jun

2007, 28(1): 68-72.

Abstract(15) PDF(1)

Abstract:
The recrystllization temperature of Ti-IF steel in batch annealing process is tested,the results show that the recrystllization temperature decreases as the prolongation of heat insulating time under the experimental condition.The recrystllization temperature are 650℃and 640℃when the heating insulating time are 1h and 3h respectively.As the heating speed has little effect on the mechanical properties of Ti-IF steel,so a reasonable high heating speed could be adopted in the batch annealing process,such as 60℃/h.In order to uniform the temperature of steel coils and enable the cold spot to achieve the given temperature,the control temperature should be at upper limit during the batch annealing,and the heat insulating time should be long enough to enable the steel recrystallize completely.Under above control conditions,the Ti-IF steel cold rolled sheet produced by batch annealing has excellent and steady mechanical properties.

2007, 28(1): 73-76.

Abstract(10) PDF(1)

Abstract:

2007 Vol. 28, No. 1