Steelmaking

Controlling on the quality of special steel billet produced by BOF-LF-CC process

CAI Kai-ke;SUN Yan-hui;QIN Zhe

2008, 24(03): 1-6,16. doi:

Asbtract ( 1913 )

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Quality of finished steel product were effected by billet quality produced by BOF-LF-CC process. In this paper, [C] controlling in BOF, deoxidization and inclusions controlling, molten steel composition, top slag controlling and billet Internal quality were analyzed by anther experience and references. The demand of special for middle/high carbon strand must be content as follow us: the molten steel composition controlling in a narrow rang, molten steel being clean(T.O about 20ppm), billet Internal steel qualing free defect (minimized shrinkage ), billet centre element (C, Mn, S, P)segregation should be minimizing. According to the practice production of home and abroad, the demand mentioned above can be met by reasonable technology in BOF-LF(VD)-CC process.

Practice of improvement in life of hot metal desulfurization lance

YIN Wei-ping;LI Zhong-yang

2008, 24(03): 7-9. doi:

Asbtract ( 1860 )

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According to the damage principle of desulfurization injection lance in No.1 Steelmaking Plant of Jinan Iron&Steel Group Co.,the injection life is increased from 200 minutes to above 900 minutes and the problem of injection lance blockage is settled successfully by improving the lance structure, optimizing the product process of injection lance and raising the performance index of refractory material.

Optimizing manufacturing management and increasing LF productivity

DONG Jin-gang;TANG Li-xin

2008, 24(03): 10-12. doi:

Asbtract ( 1755 )

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Because of the increased demand of the quality steel by the down-stream process and market since the commissioning of the 4th Blast Furnace the LF process has turned to be one of the bottlenecks affecting productivity and logistics in the 1st steelmaking Plant. On the basis of analysis on the factors affecting the LF productivity, a series of technological measures have been adopted including optimization of the refining process, production flow and production management and etc. As the results the ratio of non-LF process steel has been decreased and the LF productivity raised up.

Change in cleanliness of GCr15 bearing steel in LF refining

ZHANG Shu-hai ;XING Mei-luan; HAOYan-ying; SUN Yu-chun

2008, 24(03): 13-16. doi:

Asbtract ( 1895 )

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This paper investigates the oxygen content and non-metal inclusions of the GCr15 bearing steel in each and every phase of the LF refining process. The results indicate that in the existing process conditions the oxygen content of steel has been reduced to a lower level through 15 to 20 minutes of LF refining. The appropriate time for soft blowing upon completion of LF refining is proved to be about 15 minutes. The dimension of the non-metal inclusions at the end of LF process is below 15μm; To reduce the secondary contamination of steel the casting process should be strengthened.

Development on multifunction refinement technology of argon-blowing station

YIN xiang-bing;HUANG cheng-hong;LI ju-zhong

2008, 24(03): 17-20. doi:

Asbtract ( 1931 )

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After argon-blowing station reformation of NO.2 Steel-making Plant of WISCO, the molten steel argon-blowing refinement can satisfy the actual production more.After over one year developping ,the argon-blowing station has following various functions: CAS argon -blowing in ladle of molten steel 、 tiny adjustment composition Si, Mn, Ti, Nb, tiny adjustment temperature degree, tiny adjustment composition Als through feeding Aluminum line、tiny adjustment composition C through feeding Carbon line、adjustment temperature degree and sampling of RH molten steel 、 improve argon-blowing success rate through trying blowing Argon before tapping steel,, lower the production cost and cut process time greatly.

Research on matching productivity in BOF-LF-CCM processin Xingtai Iron & Steel Co., Ltd

YIN Jia;LIU Qing;TIAN Xin-zhong;HU Li-ning

2008, 24(03): 21-24. doi:

Asbtract ( 1896 )

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On the basis of research of the current productive operation of BOF steelmaking workshop in Xingtai Iron & Steel Co., Ltd, and proceeding from the basic parameters of the mass quantity the present paper analyzes the capacities of the converter, ladle furnace and continuous caster in the process of converter steel-making and probes to the mode of match of the steel-making flow.

Experimental study on simulation of injection desiliconization in ladle

YANG Shi-shan;LIU Zhi-min;LIU Sheng-tao;GUO Qiong;WEI Yao-huan;LI Zhi-qiang

2008, 24(03): 25-29. doi:

Asbtract ( 1907 )

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An experimental study was carried out on simulation of hot metal injection desiliconization in ladles by way of multi-batches top addition of desiliconization reagents plus partial immersion blowing of gaseous oxygen in SiC tube furnace at 1350℃. Three kinds of desiliconization reagents can all meet the requirements of injection desiliconization in ladles with desiliconization capacity of LD dust > mill scale > iron concentrates. Partial immersion blowing of gaseous oxygen can obviously increase the desiliconization velocity and greatly shorten treatment time. The optimum compositions and usage of the injection desiliconization reagents are recommended and the coverter dust without addition of CaO is proved to be the best desiliconizer.Using it as the desiliconizer not only the wear of the grinding machinery can be reduced, but the power consumption in operation also greatly lowered.

Study on refiing high phosphorus hot metal by combined blown converter

WU Wei;LIU Liu;LI Jun;GAO Jian-jun;LIU Guang-zhi;MA Zhi-ming;LI Yutian;REN Jian-zhong

2008, 24(03): 30-32. doi:

Asbtract ( 1859 )

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The experimental study is carried out on hot metal pretreatment (dephosphorizatin) and steel-making using w(P)=0.28%~2.02% hot metal as starting material in a 500kg induction furnace in simulation of a top-bottom combined blown converter. Results show that the dephosphorization rate of the hot metal arrives at 67% to 86% in the initial dephosphorization pretreatment stage and upon completion of decarburization in steel-making the dephosphorization rate cliimbs to as high as 86% to 97%. The primary factors affecting the dephosphorization rate of the hot metal are basicity of the converter slag, oxygen supply rate and temperature of bath.

Al behavior with the equilibrium of C12A7 slag and alloy structural molten-steel

CHEN Bin; JIANG Min; BAO Sarina; WANG Xin-hua

2008, 24(03): 33-36,6. doi:

Asbtract ( 2056 )

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Research shows that after 90min reaction of the alloy structural molten steel (chemical compositions of the steel similar to 42 CrMo) with C12A7 slag which is composed of w(SiO2)=6%，w(Al2O3)=46%，w(CaO)=48% w(SiO2)=6%，w(Al2O3)=46%，w(CaO)=48% , the dissolved Al content in steel is W(Al)=(80~100) x10-6 in equilibrium with W(T.O)=(6~13)x10-6 and most of the resulting inclusions are low melting point, globular and very fine calcium-magnesium-aluminium silicate inclusions in molten steel.. By thermodynamic calculations, the content of Al under equilibrium between C12A7 slag and alloy structural molten steel has been achieved in this paper. This paper also explains the reason why the low Al content can reduce the content of total O to a very low point under equilibrium in steel.

Study on final solidifying point of continuous casting billet

LUO Sen;ZHU Miaoyong;ZHANG Shuyan;Wang Zhongying;Tong Taiqin;Cai Yunteng

2008, 24(03): 37-39. doi:

Asbtract ( 1995 )

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The position of final solidifying point of the continuous casting billet is very important for determination of F-EMS. In the present paper, a mathematical model to describe the solidification process of continuous casting billet is established according to the actual conditions of steelworks, and the model is validated by the measured data obtained by pin-shooting of billet. The results show that the present model can predict the position of final solidifying point and provide reasonable data for F-EMS.

Mathematical simulation study on steel casting process from a 40 t ladle

ZHAO Xin-kai;SUN Ben-liang;LI Cheng-wei;WANG Lin

2008, 24(03): 40-45. doi:

Asbtract ( 2035 )

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Using the commercial software pack of CFD, simulation of casting process from a 40t ladle is carried out and the law of hot metal flow in the ladle in stand still as well as in the ladle in casting is determined.Results of research show that when the ladle is in a state of stand still the temperature gradient goes up gradually and the hot metal flows cyclically downwards and the flow rate slows down gradually and prior to casting inertia gas has to be blown into the ladle at a critical blow rate for 3 minutes in order to eliminate the temperature gradient; and in the process of casting the hot metal in the ladle flows cyclically upwards. According to the simulation of the critical height a straight line can be drawn up and this line can be used as a referrence for determination of the real critical height in the practical production.

Comparison and analysis on high temperature ductility of high quality pipeline steel

LIU Yang;WANG Xin-Hua;YAN Tao;ZHANG Jiong-ming;ZHANG Kai-jun

2008, 24(03): 46-49,5. doi:

Asbtract ( 1956 )

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The present paper studied and compared the high temperature ductility of slabs of pipeline steels X60, X65 and X70 by means of a thermodynamic simulator Gleeble －1500 and analyzed their fractography and metallic phase tissue by SEM and optical microscope.The conclusions derived from the above-mentioned analysis is as follows: in the high temperrature brittle zone (T1~1300℃) the ductility of the steel is primarily affected by carbon content in steel and X70 shows better ductility in comparison with that of other two steels; and in the high temperature-high ductility zone (1100℃～1300℃) the ductilities of all three steels are excellent because no brittlement occurs in the zone when the strain rate in the experiment is less than 10 2/s; and at the upper side of the ductility trough（900℃～1100℃）precipitation of the low melting point sulfide, weakening of the grain boundary and difference of the dynamic recrystallization temperatures lead to obvious difference of ductilities of two steels; and in the dual-phase zone of the ductility trough (700℃～900℃）occurrence of the precipitated proeutectoid ferrite is assumed to be the primary cause to the extra-ordinary low ductilities of all three steels and existence of MnS and Ti can promote formation of ferrite in the crystal interior and at the grain boundary simultaneously; and at 750℃ below the ductilities of all three steels are improved, and the ductility of steel X65 recovers faster.

Analysis and research on the electrode automatic control system in ladle furnace

CUI Wei;LI Hua-de;Zhang Wei

2008, 24(03): 50-54. doi:

Asbtract ( 1955 )

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Electrode control system of ladle furnace is a nonlinear, parameter-time-varying, hysteresis coupled system and for the mode of the original PID control it is very hard to achieve the good control performance. Proceeding from the actual production conditions of BAOGANG the present paper anlyzes and studies the automatic control system of the PID electrode, the artificial neural network control pattern of LAF mode , the algorithm and the applicable structure of impedance control.

System CAE simulation analysis of the new type 170 t ladle

LUO Hui-xin;CHEN Wen-juan;WU You-ming;JIANG Bin;ZHANG Chen-bin

2008, 24(03): 55-58. doi:

Asbtract ( 2021 )

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Ladle is a sort of important component in continuous casting production line. Its thermal stress is a major factor that affects its service life . In this paper the temperature and stress distribution of the Wuhan iron & steel Corporation’s new type 170 t ladle positioning at the zero tilting angle in the process of teeming the hot metal from the ladle has been simulated using the finite element method. It provide a theoretical guideline for daily maintenance and equipment optimization of the new type ladle.

Reutilization and perspectives of the metallurgical waste slag

YANG Shuang-ping;;LI San-jun;Liu Xin-mei

2008, 24(03): 59-62. doi:

Asbtract ( 1904 )

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This paper presents the sources, classification, composition and present situation of the metallurgical waste slag. It also summarized the new development of the methods in reutilization of the metallurgical waste slag in steel making, analyzed the advantages and limitations of these methods, and finally proposed the possible direction of the study on this area.

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