Steelmaking

Practice of digitized control technology of converter shape

HUANG Biao-cai

2008, 24(02): 1-3,14. doi:

Asbtract ( 2255 )

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By quantitatively depicting the dynamic changes in the furnace shape of the 100 t combined blown converter with the digitized control technology and thereupon taking some appropriate shape control measures in Fujian Sansteel, not only converter lining safety and stable production during a campaign are ensured, but the top and bottom combined blown converter service life is also extended to 20046 heats synchronously.

Application of mould breakout prediction technology

WANG Hong-feng;ZOU Jun-su

2008, 24(02): 4-6,10. doi:

Asbtract ( 1930 )

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The present paper introduces the mould breakout prediction technology and application of this technology in the production practice in the No.2 Slab Caster of MEISHAN Steel-making Plant. By analysis on the different kinds of the alarm information from the mould breakout prevention system the problems existing in the production can be found out and the operation and process of the continuous casting production further be improved. And moreover the mould breakout prediction and prevention system can be further perfected by application of the intelligent automation.

Application of ladle slag modifier in refining Q345C in LF

WANG Shi-jun;ZHANG Feng;LIU Xiao-chen;LIU Yan-ping;TAO Chuan-jun

2008, 24(02): 7-10. doi:

Asbtract ( 2033 )

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The application of ladle slag modifier in production of aluminum steel Q345C in a 50t LF is introduced. Results show that since application of the experimental ladle slag modifier in the steel production the aluminum yield has been increased, deeep desulphurization and deep dephosphorization of the hot metal intensified, the TFe content in the refining slag dramatically reduced, the mechanical properties of rolled stocks greatly improved and the cost of production for Al containing steel decreased

The study of nonmetallic inclusions in continuous casting big blooms

YANG Yu;PANG Zhao-fu;CHEN Xin;JIN Ji-yong

2008, 24(02): 11-14. doi:

Asbtract ( 2041 )

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The article did the detailed analysis of the distribution of the inclusions in different parts of the continuous casting square blooms. The results show that the first blooms of the first stove apparently contains much more inclusions than others. The sulfide inclusion is mainly in the form of ferric sulfides; The oxides inclusion is mainly in the form of silicon dioxide; It is also found that the amount of inclusion at about ¼ of the inner and outer arc and ¼ lengths from left and right is much more than other places.

Physical simulation and practice of molten steel fluidity

CHEN Shu-sen;CHENG GUO-guang;CHENG Zi-jian;CHENG Dong-quan;

2008, 24(02): 15-18,3. doi:

Asbtract ( 1923 )

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In order to improve the availability of the tundish the structural parameters of the flow control devices with different weir,dam and turbulence inhibitor was optimized to increase the retention time of the hot metal so as to remove inclusions as much as possible and improve the uniformity of temperature and compositions of the hot metal in tundish and to reduce the dead zone in the tundish and ensure a full mixture zone in an appropriate size and a plug volume zone. The present paper studies the tundish of the slab continuous caster in JISCO. A 1:3 scale water model simulating the hot metal flowing from ladle, long nozzle to tundish is established. By measuring the RTD curves in the water model the retention time, peak time and mean residence time are obtained and by calculating these time values the structure of the tundish is optimized.

Water model simulation on liquid steel level fluctuation of cast mould at No.2 Steel-making Plant of TISCO

XU Fang-hong;LI Liang;IANG Zhou-hua

2008, 24(02): 19-21,6. doi:

Asbtract ( 1957 )

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The effects of entry angle and submergence depth of the nozzle as well as the casting speed on fluctuation of the liquid steel level of the mould have been researched by water model simulation of cast mould in the No.2 steel-making Plant of TISCO. In the experiments the appropriate casting speed values are determined to be 0.8 m/min, 0.85 m/min and 0.9 m/min separately, and the entry angle determined is 10, 12 and 15 degree respectively and the submergence depth is controlled within the limit of 60~160mm (20mm space) in light of the practical production conditions. It’s verified out of the experiments that the effect of the entry angle of the nozzle and the drawing speed on the liquid level fluctuation is of insignificance, whereas the effect of the submergence depth of the nozzle on the liquid level fluctuation is very prominent. Experimental results show that the down- grade ratio of the cold rolled stainless steel sheet 0Cr18Ni9 has been lowered to 4.80 % from 6.38 % since the readjustment of the submergence depth of the nozzle to 130mm from original 110mm.

Research and application of thermo-mechanical stress model for bottom working lining of 250～300 ton ladle

JIANG Guo-zhang;KONG Jian-yi;LI Gong-fa;TAO Xiao-lin;HU Tie-shan

2008, 24(02): 22-25,4. doi:

Asbtract ( 2014 )

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Ladle is a sort of important equipment in the metallurgical industry and its lifetime is of direct influence on the normal production of the whole enterprise. Five structural models of ladle bottom have been established and bottom stress distributions of these models calculated by using finite element method. Then the model of the fifth scheme is determined to be the best one by comparison of each with other and then this model is applied to actual production of ladle. Application of the model on site indicates that ladle’ lifetime is greatly improved. Verification on the model of the fifth scheme demonstrates that this method is feasible to improve ladle’s lifetime.

Research on erosion of AOD final slag to MgO-CaO refractory

ZHENG Hong-guang;ZHU Fang-yi;LIU Tao;CAI Ci;SHI Jin-hong;CHEN Wei-qing

2008, 24(02): 26-29. doi:

Asbtract ( 1988 )

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The influence of the slag basicity, MgO, CaF2 and Al2O3 content in AOD final slag on erosion of MgO-CaO lining is investigated. The erosion of the same slag onto the MgO-CaO crucible with different CaO content is compared. The reaction layer of slag-refractory is analyzed by means of the Scanning Electron Microscope. The results show that the slag basicity is the most important factor to MgO-CaO lining erosion. The erosion is remarkably reduced with the increase of basicity, and with the increase of MgO content or the decrease of CaF2 content in slag. It is also observed that the erosion resistance to CaO-SiO2-MgO slag is enhanced with the increase of CaO content in MgO-CaO refractory.

Discussion on conditions for hot metal deep dephosphorization

QI Jiang-hua;XUE Zheng-liang;LI Zong-qiang;ZHAO Dong-nan

2008, 24(02): 30-33. doi:

Asbtract ( 1942 )

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Deep desulfurization experiments have been repeatedly conducted in the induction furnace. Through theoretical and experimental analysis on the effects of the initial sulfur content, desulphurizing refining slag, oxygen content and slag amount in the hot metal on the hot metal deep desulphurization a few main conditions required for hot metal deep desulphurization in the inducton furnace have been determined.

Microstructures and properties of V micro-alloyed hot rolled dual phase steel

WANG Yin-feng;HE Yi-zhu;SU Shi-hua;HU Xue-wen

2008, 24(02): 34-37. doi:

Asbtract ( 1941 )

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the present paper studies the micro-structures and properties of the test piece of V micro-alloyed hot rolled steel and analyzes precipitation of elements V(C,N) and the strengthening mechanism of the precipitates on strength of the testing piece. Results show that the micro-structures of the test steel are composed of polygon ferrites, bainites and trace of martensites and the average grain size of the polygon ferrites is about 7µm, the tensile strength of the steel is over 570 Mpa and the mechanical properties are excellent. The TEM observation shows that there are precipitated V(C,N) particles in the steel. Precipitation may occur randomly in the ferrites or along the dislocation line. The strength of the test steel can be enhanced through precipitation of the second phase particles V(C, N).

Laboratory study and mechanism analysis on deoxidation of barium alloy in clean steel production

WANG Zhong-ying;WU Xiao-dong;LIU Xing-guo

2008, 24(02): 38-41,4. doi:

Asbtract ( 1884 )

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The effects of hot metal deoxidization by Barium alloy in steel-making process have been studied from the point of view of bearing steel production. The results show that once the oxygen in steel is rapidly reduced to a specific stable level the Barium containing inclusions will be very easily removed from the molten steel and the total inclusions of ingot or billet are reduced obviously. Therefore the molten steel can be purified if the Barium alloy is used to treat the steel.

Optimization geometry of submerged entry nozzle for bloom continuous casting mould

GAO Ze-ping;SU Zhen-jiang

2008, 24(02): 42-45. doi:

Asbtract ( 1728 )

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By physical simulation the surface fluctuation, impacting pressure and impacting height as well as covering of flux of the designed mould series under the various working conditions have been measured and analyzed and by optimization of the measured values the best nozzle is found out, then the characteristics of the flow field and temperature field of the liquid steel in the mould of the selected nozzle are analyzed by application of the flow field calculation software FLUENT and water model, and thereupon the geometry of the submerged nozzle best suitable for the bloom continuous casting is selected and verified in the practical production..

Industrial scale experimental study on foaming behavior of slag for stainless steel-making

FAN Rong-wei;MENG Qing-yu;HONG Xin;ZHANG Mei-ming;LI Qing

2008, 24(02): 46-49. doi:

Asbtract ( 1889 )

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On the basis of results of the laboratory study on the low fluoride carbonate foaming slag the industrial scale experiments on foaming behavior of the slag have been carried out in a 100t EAF in refining stainless steel in Baosteel. Results show that the newly developed foaming agent has excellent foaming behavior, and the foaming behavior is related to the way of addition and the particle size of the foaming agent. The optimal way of the foaming agent addition is obtained by summarizing the experimental results and the influence of particle size on the slag foaming behavior analyzed in detail.

Preparation and application of bauxite-based prefabricated block for electric furnace roof

ZHU Hong-xi; DENG Cheng-ji; BAI Chen; GE Shan; LIU Kui-ran; ZHONG Xi-qing

2008, 24(02): 50-53,5. doi:

Asbtract ( 1813 )

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In light of actual conditions of undesirable performance of the refractory blocks previously used for EAF roof, a kind of prefabricated monolithic refractory block which is easy to be assembled and fixed up for the block-type EAF roof has been designed and manufactured. .The effects of such a few processing factors as the grain sizes and shapes of the particles as well as the binder, additive and dehydrating agent on the performance of the prefabricated block for EAF roof have been investigated. The optimized aggregate composition of the bauxite based prefabricated refractory block used in the electric furnace roof involve grain size in 8～5mm 10%:5～3mm 20%:3～1mm 20% and1～0mm 20% and the refined powder takes up 30% of the total. The ingredients of the binding materials are composed of 5 % CA80 cement, 3 % silica micro-powder or 3 % ~ 5 % ultra-fine alumina powders, and 0.2 % trimeric sodium phosphate and hexamet sodium phosphate. The bauxite based prefabricated blocks for EAF roof produced in this way have been used in a number of steel-making works and very satisfactory results have been achieved. It’s reported that in a specific steel-making works the campaign life of the EAF roof made of this block exceeds 600 heats.

Investigation of active lime liquation in initial slag of steelmaking

MENG Jin-xia;CHEN Wei-qing

2008, 24(02): 54-58. doi:

Asbtract ( 1954 )

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Influences of lime calcination temperature as well as compositions and temperature of slag on active lime liquation in initial slag of converter steelmaking are investigated by means of the rotating cylinder method. The results show that liquation rate of active lime calcined at 1000℃ reaches the highest. Increase of FeO, less MgO content and lower slag basicity, and higher temperature are in favor of active lime liquation in slag. Process of active lime liquation in initial slag of converter contains the surface dissolution and the lime metamorphism disaggregation due to penetration of slag, in which case the latter is crucial.

Progress of oxygen lances in EAF steelmaking

WANG Zhen-zhou;ZHU Rong

2008, 24(02): 59-62. doi:

Asbtract ( 1854 )

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How to effectively inject oxygen into the EAF and accelerate melting of the scrap steel is key to speeding up EAF melting process. The present paper summarizes the characteristics of development and application of oxygen Lances used in EAF at home and abroad, introduces and compares their characteristics one by one and thereupon foresees their prospects of application in EAF refining in the future.

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