钢铁钒钛

Study on High Temperature Smelting Hydrogen Metallurgy

Cao Chaozhen, Guo Peimin, Zhao Pei, Pang Jianming

2009, 30(1): 1-6.

Abstract(20) PDF(1)

Abstract:
It was studied by thermodynamics calculation in different patterns that the feasibility of decreasing the heat burden of melting furnace by blowing hydrogen to replace C as reducing agent in this paper.The results showed that the heat burden of melting furnace can't be reduced by blowing hydrogen for the current smelting reduction processes,but it can be realized by modifying the current smelting reduction processes by reducing the quantity of coal injection and increasing the quantity of hydrogen injection to make the C:0 lessthan 1:1.Exclusive-hydrogen smelting reduction can realize green metallurgy,but it should be further developed.

Recovering Vanadium from High Carbon Stone Coal by Means of Direct Acid Leaching

Wei Chang, Wu Huiling, Fan Gang, Li Cunxiong, Li Minting, Liang Yanhui

2009, 30(1): 7-11.

Abstract(21) PDF(1)

Abstract:
Based on high carbon stone coal of Guangwang of Sichuan,on the basis of chemical analysis, petrographic analysis and electron probes, recovering vanadium experiment from high carbon stone coal by aid leaching was carried. The result show that the optimum vanadium extraction rate is respectively 54.7% and 72.86% after one and two steps atmospheric leaching and two pressure acid leaching. This two methods do not have high leaching rate of vanadium, because of high carbon content and minerals of stone coal, and carbon have a complex behavior in the leaching process.

Study on Solubility Properties of Fluidizing Chlorination Slag for Titanium-rich Material

Xu Qingxin, Lei Ting, Zou Ping, Wang Xiangding

2009, 30(1): 12-15.

Abstract(22) PDF(2)

Abstract:
In allusion to the process of titanium white powder produced by chloride giving rise to a large number of fluidizing chlorination slag,which will cause the serious environmental problems if it was directly stacked. We will introduce a new kind of water-soluble way,by which chloride is dissolved in water as much as possible and we can gain some useful matters through filtering,at last,the remain solid waste residue will be sent to the landfill residue,then environmental pollution decreased.The solution properties of fluidizing chlorination slag for titanium-rich material were researched,the results showed that the optimum solution conditions are pH = 1,liquid-solid ratio 4:1,the reaction time 30 min,room temperature(about 20℃),On this condition, the main removal of metal ions of this boiling chlorination slag is over 90 percent.

Variation Characteristics of Microstructures in Non-quenched and Tempered Steel with Vanadium and Nitrogen

Liu Hongyu, Liu Jianhua, Huang Gang, Chen Xiaolong, Yu Chenglu, Ke Xiaotao, Li Haibo

2009, 30(1): 16-22.

Abstract(22) PDF(1)

Abstract:
The microstructures of non-quenched and tempered steel with different vanadium and nitrogen contents, cooled to room temperature at different cooling rates after being deformed in austenite,were observed and analyzed using optical microscope,scanning and transmission electron microscope.The results indicate the amount of pearlite increases as nitrogen increases or vanadium decreases.A large amount of nano-precipitates with size less than 3 nm were found in both pre-eutectoid and eutectoid ferrite.With cooling rate increasing, ferrite fined and its amount decreased,bainite and martensite appeared as cooling rate increased further, meanwhile,the sizes of vanadium and titanium precipitates fined and main compositions changed from (Ti,V)N to(Ti,V)C.

Influence of Titanium Content on Microstructure and Mechanical Properties of Hot-roHed Strips

Huo Xiangdong, Mao Xinping, Chen Kangmin, Lin Zhenyuan

2009, 30(1): 23-28.

Abstract(29) PDF(2)

Abstract:
Based on chemical composition of common container strips,titanium micro-alloyed high strength steel was developed by CSP process.Many experimental methods,such as SEM,TEM and chemical phase analysis,were used to study the effect of titanium content on microstructure and mechanical properties of hotrolled strips.The results summarized as follows,titanium content had no obvious influence on ferrite groin size of steel.With titanium content increasing in steel,titanium nitrides coarsened and the volume fraction of titanium carbides increased and average dimension of TiC decreased.Large amount of precipitates,the size of which is less than 5 nm,were found in steel with 0.106%Ti.High strength steel can be attributed to precipitation hardening of these precipitates.

Dissolution Behavior of Nb,Ti Carbonitride Precipitates in Low Carbon Microalloyed Steel

Wu Xinlang, Zhao Zhengzhi, Yu Wei, LI Bin, Wang Lun

2009, 30(1): 29-33.

Abstract(24) PDF(1)

Abstract:
Dissolution behavior of Nb,Ti carbonitride precipitates in low carbon microalloyed steel was studied by use of TEM and EDX.It is found that with the heating temperature rising and hold time increasing,the second-phase particles dissolve.The dimension of the second-phase particles becomes finer and the number of them is decreasing gradually.At the same time,morphologies of particles become the near cuboid form from the like sphere.Both Nb,Ti carbonitride precipitates will dissolve,and the dissolving rate of Nb is faster than that of Ti.

Study on Microstructures and Properties of Ultra Low-carbon Nb+Ti-IF Steel

Li Yaobing, Zhou Huan, Su Lan, Zhao Aimin

2009, 30(1): 34-40.

Abstract(18) PDF(1)

Abstract:
Under the laboratory conditions,the crystallizing regulation and the effect of annealing process on the properties and structure of Nb+Ti-IF steel were studied,the experiment showed that:the starting crystallization temperature of IF steel is 680℃, under 800℃ constant temperature conditions,the time of finished crystallization is 60 seconds.Taken together,when the annealing temperature is 870℃,we get the excellent properties:tensile strength is 313 MPa,yield strength is 156 MPa,elongation is 50.8%,n-value is 0.281, r-value is 2.07. The annealing texture is made of strong γ fiber and weak a fiber texture,γ-fiber texture is mostly composed of {111}〈110〉texture and {111}〈112〉texture, {111}〈112〉texture is dominant.

Development and Application of Ti Micro-alloying High Strength Weathering Steels in Zhujiang Steel

Lin Zhenyuan, Mao Xinping, Yu Chibin, Zhao Gang

2009, 30(1): 41-45.

Abstract(28) PDF(1)

Abstract:
In thin slab continuous casting and continuous rolling process,by researching the Ti micro-alloying technology,the problem of mechanical performance undulation with Ti micro-alloying was solved effectively, and high strength weathering steels were developed,the yield strength is 450~700 MPa.The microstructure performance and the industrialized application of steel were studied,which shows that the tested steel has better the mechanical performance all of the coil along longitudinal direction,the forming performance and the welding performance,The quality of the tested steel satisfies the request in the container and the automobile manufacture industry,and it has the broad market prospect.

Study on the Residence Time Distribution Characteristics of T Type Eight-strand Continuous Casting Tundish

Chen Yuanqing, Wang Xuebing, Chou Shengtao, Peng Shiheng

2009, 30(1): 46-50.

Abstract(18) PDF(1)

Abstract:
Based on the principle of similarity,1:2 physical model of eight-strand continuous casting tundish is built.Water modeling experiments are carried out to measure the residence time distribution of the fluid in the tundish.A method for analyzing the RTD curve of multi-strand tundish is presented by deducing,which is then used to analyze the average residence time,flow pattern and the flow uniformity of different lines.After that,the optimized case of flow control device is chosen.Study shows that case 3 can obviously improve the flow characteristics in the tundish.

Study on the Metallurgical Effects of Electric Pulse Acted on Molten Steel in Tundish

Gu Wu'an

2009, 30(1): 51-54.

Abstract(29) PDF(2)

Abstract:
The metallurgical effects of electric pulse acted on molten steel in the tundish of Panzhihua Steel were studied,including the element segregation improvement for casting slabs and refining crystal structure. The results show that,the equiaxed crystal ratio could be 53% to 91%,average was 66%, which was higher 45% than that without electric pulse treatment;the center segregations of C,S&P of casting slab have been significantly reduced with increasing of the electric current and the frequency of electric pulse,mechanics property of hot roiled strip was better after the treatment of EP.

Water Model of the Surface Wave and Fluid Flow in Slab Continuous Casting Mold

Wang Yongsheng, Hou Zewang, Wang Xinhua, Wang Wanjun

2009, 30(1): 55-59.

Abstract(26) PDF(1)

Abstract:
According to one kind of the molds for slab caster in china,a water model in the ratio of 1 to 1 has been established in order to study the effect of the level of steel in tundish on flow field and surface wave of mold.The results show that the flow field and surface wave of molten steel in the mold was changed with the unsteady the level of steel in tundish,at same time,Increases of the surface wave of mold owed to the change of the stress and velocity of steel flow on SEN outlet though changed the level of steel in tundish.The best level of steel in tundish is 800 mm.It is proposed that we keep the steady level of steel in tundish in order to produce the higher quality steel.

Measurement of the Solidified Shell Thickness in the Secondary Cooling Zone of Continuous Casting of Bloom

Chen Yong, Wu Guorong, Sun Yanhui

2009, 30(1): 60-63.

Abstract(27) PDF(1)

Abstract:
The solidified shell thickness of bloom near the final stage of solidification in the secondary cooling zone on Pangang No.2 continuous bloom caster was measured,by use of the pin-shooting method.On the basis, the relationship between the solidified shell thickness,the final stage of solidification of bloom and casting speed,secondary cooling intensity wag obtained.The research results have provided the important basis for optimizing continuous casting process,controlling the final stage of solidification and establishing reasonable process parameters of soft reduction.

Impact on the Instability of Carbon Content of IF Steel

Chen Liang, Chen Tianming, Zhang Guifang, Ceng Jianhua, Shi Zhe, Gu Longjian

2009, 30(1): 68-73.

Abstract(20) PDF(1)

Abstract:
In this paper,it aim at Panzhihua Steel RH refining process in the high carbon content and instability in IF steel production.its production process tracking survey shows that the impact of the carbon content of the main factors are RH initial steel [C] and a_[o],vacuum degree,decarburization time,carbon picking-up in molten steel caused by ladle refractory materials and alloys about Carbon Control of RH Refining Process for IF Steel in Panzhihua iron and steel company(PZHISC).If the carbon content is more than 0.045%,the end carbon content increases by initial carbon content.If the lowest vacuum degree is lower and progressing time is longer,the end carbon content is higher.To ensure that the carbon content of Panzhihua Iron and Steel IF steel qualified,initial [C] and a_[o] should be controlled of 0.030%~0.045% and(500-700)×10^-6, strengthen monitoring and maintenance of RH equipments are both needed to maintain adequate deep vacuum time and further reduce the vacuum degree.Also,in order to reduce the carbon picking-up in molten steel during the latter part of RH process,on the premise of ensuring no solid steel on vacuum chamber,the ladle with a carbon-free slag line and low-carbon alloys should be used.

Discussion on Serialization of Mold Fluxes for Continuous Casting Billets in Shuicheng Steel

He Shengping, Wang Lijuan, Wang Qian, Zhang Jiaxiang, Zhang Dongsheng

2009, 30(1): 64-67.

Abstract(19) PDF(1)

Abstract:
Mold fluxes play an important role in maintaining the continuous casting process and improving surface quality of casting strands.Due to the difference of steel grades and continuous casting process,appropriate properties of mold fluxes are not the sarne.Aiming at the process of continuous casting billets,serialization of mold fluxes for billets was discussed by analyzing the solidification characteristic of the steel grades.Based on the matching relation between properties of mold fluxes and surface quality of casting strands,serialization of mold fluxes for low carbon steel,medium carbon steel and high carbon steel casting billets in Shuicheng Iron and Steel (Group) Co.,Ltd (Shuigang) was planned.

2009 Vol. 30, No. 1