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Steelmaking 2013 Vol.29 Please wait a minute... For Selected: Download Citations EndNote Ris BibTeX Toggle Thumbnails Select Production practice of high hot metal ratio refining pattern in 120 t converter Steelmaking    2013, 29 (1): 1-3,14.   Abstract （400）            Knowledge map    Save To realize the benefit maximization the offgas analysis and dynamic control technology as well as temperature control technology by addition of burnt dolomite in the ore are applied to solve the problem of severe temperature and composition fluctuation, high probability of splashing and low end point hit ratio due to surplus heat and realize the targets of w(P)＜0.015 % in tapping, 91.2 % of dual hit ratio of end point C-T, reduction of the slag materials such as lime from 87.1 kg/t to 79.5 kg/t and decrease of the metal loss from 10.3 %to below 8.7 %in refining the low carbon and low phosphorous steel series with high hot metal ratio in the 120 t BOF converter in No.1 Steel Making and Rolling Mill in Maanshan Iron &Steel Co., Ltd and very satisfactory results have been achieved in reduction of production cost and material consumption. Related Articles | Metrics Select Production practice of refining aluminum steel by argon blowing Steelmaking    2013, 29 (1): 4-6.   Abstract （410）            Knowledge map    Save The present paper introduces how to solve the influence of the deoxidizing products Al2O3 on quality of liquid steel and castability in the process of casting by optimization of deoxidization process and application of Ca treatment and realize consistent production of Al steel by "converterargon blowcontinuous casting" process route and thus tension of production of brand steeel by LF is relieved and the production cost is reduced as well without affecting the product quality in the over moded section of the steel making plants of Chongqing iron & Steel Co., ltd. Related Articles | Metrics Cited: Baidu(1) Select Production practice of optimization of low carbon and low silicon SPHC steel refining process Steelmaking    2013, 29 (1): 7-10.   Abstract （344）            Knowledge map    Save In combination with the basic situation of SPHC steel in a specific plant, the characteristics and the main problem of the process are analyzed. Based on the process optimization, the desulfurization rate has been raised to 45.5 %from original 35.7 % and the ratio of inclusions in the slab less than 1.0grade comes up to 80 % . Thus quality of SPHC steel has been highly improved and the production cost Related Articles | Metrics Cited: Baidu(2) Select Technical development and application of 3D spray technology for 400 mm ultrathick slabs Steelmaking    2013, 29 (1): 11-14.   Abstract （340）            Knowledge map    Save Influences of slab thickness and 3D spray technology on the transverse corner cracks are analyzed. Results show that for the 400 mm ultrathick slab the mechanical properties in the low ductility region III are the internal cause and the over high cooling intensity at the corner of the slab in the leveling section is the external one for the transverse corner cracks. Thereupon a few effective measures for improvement in the transverse cracks of the 400 mm ultrathick slab are put forward. The transverse corner cracks of the slab are obviously reduced and the notching rate of the slabs is down to 0.35 % and the surface quality of slabs effectively improved. Related Articles | Metrics Select Analysis on the cause and control of disqualification of Q345R steel plate by ultrasonic detection Steelmaking    2013, 29 (1): 15-18,2.   Abstract （330）            Knowledge map    Save In view of disqualification of Q345R steel plate (Thickness range from 14 to 22 mm) by ultrasonic detection, Zdirection tensile detection and SEM-EDS analysis are carried out to find out the origins and results indicate that centerline segregation, MnS inclusion and cracks and so on are main reasons of disqualification of Q345R steel plate by ultrasonic detection. Various factors related to qualified rate of Q345R steel plate by ultrasonic detection are analyzed. Qualified rate of Q345R steel plate by ultrasonic detection have been improved by taking a series of technological measures such as low superheat casting, reducing sulfur content, increasing of stacking slow cooling time of the slab and etc. Related Articles | Metrics Cited: Baidu(1) Select Inclusions control of pipeline steel in steelmaking process Steelmaking    2013, 29 (1): 19-23.   Abstract （363）            Knowledge map    Save The high grade pipeline steel produced in a specific steel work by the BOF→LF→RH process route is investigated. The inclusions in the steel are examined and analyzed by application of certain analytical techniques such as metallographic examination、SEM and EDS and then the mechanism of formation of the inclusions is studied according to the thermodynamics. Results show that when the w(AlS) is about 0.025 % the inclusion Al2O3 in steel can be easily modified to low melting point C12A7 if w(CaO)＞18×10-6，w(S)＜0.011 % in the steel. A series of technological measures have been put forward such as intensification of the topbottom combined blown process of the converter, improvemnt in the argon blow scheme in both the argon blow station and LF facility and adjustment of the refining slag series so as to control w(CaO)/w(SiO2) within the limit of 4.5 to 6.0 and w(CaO)/w(Al2O3) in 1.7 to 1.9and finally control w(S) in below 0.000 8 %and confine the grade of oxide and sulfide inclusions in grade 1.0in steel. Related Articles | Metrics Cited: Baidu(2) Select Study and practice of converter refining process of non-quenched crankshaft steel Steelmaking    2013, 29 (1): 24-27.   Abstract （346）            Knowledge map    Save In order to come up to the standard of nitrogen content in steel the process route of “converter→LF→RH→rectangular bloom CC”has been adopted in Benxi Iron & Steel (Group) Co., Ltd. and in the full RH process nitrogen is used as the lifting gas and at the same time manganese nitride alloy is added to meet the need of nitrogen in steel. Practice shows that the process is feasible and w(N) can be strictly controlled within the limit of (110~160)×10-6. Moreover w(H) in tundish liquid steel can be effectively controlled in less than 2.5×10-6 and the results of check and examination of the steel products conforms to standards. Related Articles | Metrics Select Development of hot rolling product as the substitution of cold rolling product by boron micro-alloy technology Steelmaking    2013, 29 (1): 28-31,3.   Abstract （366）            Knowledge map    Save By taking technologies of boron micro-alloy low-carbon softening steel, strictly control the chemical compositins and nitrogen content in the liquid steel and optimization of the continuous casting and rolling processes in the thin slab casting and rolling production line(FTSR) in Tonghua Iron and Steel Co.,Ltd., the steel grade of TG270 has been successfully developed as the substitution of SPHC used for raw material of cold rolling. Both quality and mechanical properties of the products reach the requirements of customers. Related Articles | Metrics Select Study on sulfur control technology for non-orientation electrical steel Steelmaking    2013, 29 (1): 32-35,5.   Abstract （329）            Knowledge map    Save In cognizance of the problems of low desulphurization rate for hot metal, large sulfurrecovery in converter as well as high sulfur content in products in producing non-orientation electrical steel with vanadiumcontent hot metal countermeasures have been carried out. Sulfur content in non-orientation electrical steel is decreased obviously by way of study on technologies of desulphurization for hot metal with vanadium & titanium, sulfurrecovery control in converter and desulphurization in RH refining process as well. The results of industrial tests show that w（S）=0.001 9 %~0.006 9 %, and 0.004 2 %is average, the rate w（S）≤0.008 % is as high as 100 %, and the rate w（S）≤0.005 % reaches 91.43 %. Related Articles | Metrics Select Analysis on sulfur control in ultra low sulfur steel by LF-RH process Steelmaking    2013, 29 (1): 36-39.   Abstract （347）            Knowledge map    Save The present paper mainly studies how the LF slag deoxidizer, LF dynamics condition and the Ca-treatment affect the desulphurization after RH. The results show that the w(FeO+MnO) can be controlled in below 0.5 % after adding more than 300 kg aluminum particles in the refining slag and w(S) in the steel is reduced from original 30×10-6to 630×10-6; and when the bottom gas flow rate is 500 L/min w(S) in the steel can be reduced to 6×10-6 after 10 min and too high or too low blow argon flow rate will affect the desulfurization efficiency. In this research later Ca-treatment in RH has no desulfurization ability, but addition of the calcium cladded wire can inhibit the sulfur pickup and keep the sulfur content in a low level. Related Articles | Metrics Cited: Baidu(6) Select Influence of AOD processing on nitrogen content of 0Cr18Ni9 stainless steel Steelmaking    2013, 29 (1): 40-43,4.   Abstract （404）            Knowledge map    Save In light of the problem of heavier fluctuation of nitrogen content and argon consumption in steel in refining the stainless steel 0Cr18Ni9 the effects of such a few AOD pocessing factors as carbon content in the initial liquid steel, alloy element content and temperature as well as blow rate of oxygen, nitrogen and argon and blow time on the end point nitrogen content are investigated and in the meanwhile the AOD operating process parameters are studied and optimized as well. Related Articles | Metrics Select Transformation of non-metal inclusions in ultra-low oxygen steel for petroleum steel pipe in LF-VD refining process Steelmaking    2013, 29 (1): 43-47.   Abstract （303）            Knowledge map    Save The total oxygen content,nitrogen content,the formation and transformation of non-metallic inclusions and the influence of refining slag on inclusion removal in the experiment steel at each phase of EAF→LF→VD→CC process have been analyzed and studied.The results show that w(T.O) in the experimental steel drops by 42.83 % on average in the process of LF refining and after VD vacuum treatment w(T.O) and w(N) fall by 48.77 % and 10.72 % respectively. In the LF refining process the nonmetal inclusions in the liquid steel are transformed in such a proper order as “Al2O3series inclusion MgO-Al2O3series inclusion→CaO→MgO→Al2O3 series inclusion” from external part gradually to internal part, in which the transformation of MgO-Al2O3 series into CaO-MgO-Al2O3series is carried out gradually from outside to inside and CaO and MgO in the inclusion are incompatible. Control of basicity of the initial refining slag in about 2.5 will be more advantageous for absorption of inclusions in the slag. Related Articles | Metrics Cited: Baidu(7) Select Experimental study of ladle furnace desulfurization with CaO-Al2O3-SiO2 based refining slag Steelmaking    2013, 29 (1): 48-51.   Abstract （357）            Knowledge map    Save The experiment on desulfurization of molten steel using CaO-Al2O3-SiO2 based refining slag is carried in a small furnace in the laboratory. The effects of refining slag basicity, Al2O3, CaF2on desulfurization of molten steel are studied. The results show that the dusulfurization rate is over 80 % when the refining slag basicity is changed from 2.85to 3.45. However, when the mass fraction of Al2O3 in refining slag is 24 %, the desulfurization rate is 83.7 %. With the increase of CaF2 in refining slag the desulfurization rate rises initially and then falls down. The optimum composition of the refining slag is w(CaO)/w(SiO2) =3.0, w(CaF2)=7 %、w(MgO)=6 %、w(Al2O3)=24 %. Related Articles | Metrics Select Study on desulphurization slag system in RH refining process for electric steel Steelmaking    2013, 29 (1): 52-56.   Abstract （328）            Knowledge map    Save In light of the difficulty of production of high level electrical steel w(S)≤0.006 %steadily in Panzhihua steel & vanadium Co., Ltd. the process technology of RH desulfurization system has been formed by developing the RH desulfurizer, modifying the ladle slag and controlling the process parameters. Industrial experiments show that the desulfurization rate of hot metal rises to 42 % and the w(S) of the finished products is controlled in below 0.005% and total oxygen and nitrogen contents are also well controlled and no carbon pick up occurs in the hot metal due to addition of desulfurizer since this technology is implemented. Therefore requirments for production of high level electrical silicon steel grade are satisfied. Related Articles | Metrics Cited: Baidu(2) Select Study on deformation inclusions of calcium treatment on high quality pipe line steels Steelmaking    2013, 29 (1): 57-60.   Abstract （351）            Knowledge map    Save A investigation was carried on the variations of inclusion types in B(PSL1) steel before and after calcium treatment. The modification mechanism of Al2O3 and high level of CaS was analyzed by thermodynamics. The results show that Al2O3 can be modified into 12CaO·7Al2O3 inclusions which are liquid at steelmaking temperature, while majority of CaS were generated,and MnS can be completely modified partially into CaS under the present amount of CaSi wire fed. Related Articles | Metrics Select Analysis of inner cracks of AH32 steel continuous casting slab Steelmaking    2013, 29 (1): 61-64,7.   Abstract （301）            Knowledge map    Save Taking ship steel plate AH32 as the object of study the precipitation behaviour of MnS in the steel is analog computed with thermodynamics software TheroCalc and in the meanwhile the effects of change of element content on the law of MnS precipitation as well as characteristics of solidification process of ship steel plate AH32 are studied and micro observation and energy spectrum analysis on the inner cracks of the steel plate are conducted using SEM Quanta-400. It’s concluded that the primary cause to the inner crack is schistose MnS precipitant arising from eutectic reaction. A series of counter measures such as reduction of sulfur content, low drawing speed and weak cooling in the secondary cooling zone, optimization of electromagnetic stirring process and calcium treatment have been implemented and very sound results have been achieved. Related Articles | Metrics Select Analysis on reason of small surface longitudinal cracks of Q345B steel plate Steelmaking    2013, 29 (1): 65-68.   Abstract （430）            Knowledge map    Save In order to find the causes of small surface longitudinal cracks in Q345B steel plate rolled from continuous casting slab, spectrum analyzer, optical microscope, scanning electron microscopy and energy spectrum analysis are employed to examine the chemical compositions and microstructures of surface crack and type of inclusions in the cracks. The results show that cracks are caused by skin blowhole in continuous casting slab. The skin blowhole exposed and burned in the heating process prior to rolling can not be pressed due to oxidation. The defect area cannot participate in synchronous deformation in the process of rolling extension and eventually forms the small surface longitudinal cracks. Related Articles | Metrics Cited: Baidu(1) Select Design of guide baffles in tundish and metallurgical effects analysis Steelmaking    2013, 29 (1): 69-73.   Abstract （397）            Knowledge map    Save In order to improve metallurgy effect of sixstrand billet tundish, the hydraulic simulation experiments are conducted to investigate the effects of the guide holes parameters on flow field characteristics in sixstrand billet tundish in the Metallurgy Engineering Technology Center of University of Science and Technology Liaoning. And the range analysis is conducted on them. Finally it is determined that the affecting factors are diameter, height and leanangle of the guide holes. The affecting level for flow field characteristics in tundish is: diameter>lean-angles>height. Using it as the guiding ideology the guide baffles are designed by CFD numerical simulation and the diameters of three guide holes are determined to be 93 mm,72 mm and 36 mm, positions, (220 mm,140 mm),(350 mm,280 mm) and (700 mm,300 mm) and leanangle, (21°,15°),(8°,23°) and (10°,28°) respectively. Industrial experiments indicate that installation of the guide baffles in the tundish will effectively improve the characteristics of molten steel flow and increase the effect of tundish metallurgy. Related Articles | Metrics Cited: Baidu(2) Select Analysis on main quality defect of beam blank production and prevention Steelmaking    2013, 29 (1): 74-78.   Abstract （337）            Knowledge map    Save In order to improve the beam blank quality and the qualification rate of the products all factors causing formation of the defects of the beam blank have been analyzed comprehensively. The surface defects of the beam blank occur essentially in the process of shell solidification in the mould and the defects mainly involve surface longitudinal cracks, longitudinal corner cracks, transversal surface cracks, star cracks, inclusions on the surface, blow holes and concave pit. The inner defects mainly including central cracks, straightening cracks, segregations, center porosity and triangular zone cracks are closely related to over high S & P content in the hot metal, unreasonable distribution of the secondary cooling water, misalignment of the support system and surface temperature rise of the beam blank. The shape defects of which the main representation is deviation of flange parallelism, arise principally from inhomogeneous cooling on the inner and outer bow. In light of the above mentioned defects of the beam blank preventive measures are accordingly put forward. Related Articles | Metrics Cited: Baidu(1) Select Analysis on flow optimization & cost control in steel-making system Steelmaking    2013, 29 (2): 1-5.   Abstract （436）            Knowledge map    Save In this thesis,steel-making system flow is hackled,parsed and optimized in detail from process flow,time flow,material flow and information flow and by optimization of the steelmaking system flow the optimization of structure and improvement of functions of steelmaking as well as an optimal compromise between products,quality and cost have been realized. Related Articles | Metrics Select Research and practice on converter process of slag reduction Steelmaking    2013, 29 (2): 6-8,18.   Abstract （416）            Knowledge map    Save Steelmaking process of decreasing converter slag is developed for Shasteel by exploring the suitable intermediate deslagging time and blowing parameters. The blowing process is divided into two stages, dephosphorization and decarburization and upon completion of the dephosphorization process certain amount of slag is poured out and then the steel is refined again for decarburization with small amount of slag. After tapping, a small amount of decarburization slag remains in the converter for dephosphorizing of the next heat. Steelmaking using this process could reduce production cost by decreasing lime and dolomite consumption and improve the stability of steel composition by increasing the efficiency of dephosphorization. Industrial test results show that converter lime consumption is reduced to 17 kg/t steel from 26 kg/t, and dolomite consumption reduced from 13 kg/t to 9 kg/t, at the same time,the mass fraction of phosphorus could be controlled within 0.0080 %~0.0182 %，with the average content of 0.0126 %,at the end of blowing. Related Articles | Metrics Cited: Baidu(3) Select Composition optimization of LF refining slag in high cleanliness Al-killed steel Steelmaking    2013, 29 (2): 9-13.   Abstract （458）            Knowledge map    Save According to Iso-activity lines of aCaO and aAl2O3,Iso-temperature lines and Iso-sulfur capacity line of the slag system of CaO-SiO2-Al2O3 obtained by Factsage software and KTH model, the impacts of LF refining slag basicity, ratio of w(CaO)/w(Al2O3), and mannesmann index on slag melting point, sulfur capacity and Al2O3 inclusions absorption are studied in this paper; furthermore, the ideal slag of highpurity aluminum killed steel is w(CaO)=50 %～55 %，w(Al2O3)=22 %～26 %，w(SiO2)=10 %～12 %，w(MgO)=5 %～8 %. The field test of 40Cr steel shows that the mass fraction of T.O and sulfur can be controlled in below 15×10-6 and 90×10-6 respectively and its cleanness reaches domestic advanced level. Related Articles | Metrics Cited: Baidu(4) Select Optimization and research on refining slag of large tube billet Steelmaking    2013, 29 (2): 14-18.   Abstract （393）            Knowledge map    Save The refining slag series of large tube blank is studied by methods of chemical analysis,lithofacies analysis,SEM and simulative calculation.The results show that the percentage of original slag higher than 1 440 ℃is 60 % of the total melting temperature.The high proportion of 2CaO·SiO2and 3CaO·SiO2 in the slag leads to the viscosity of refine slag above 2 P·s.After the optimization and application of new slag series,the mass fraction of average total oxygen is reduced by 5×10-6,the mass fraction of average nitrogen reduced by 15×10-6,and the mass fraction of average sulfur reduced by 60 %after VD refining in the steel.The mass fraction of lowest sulphur is controlled to 0.003 %. Related Articles | Metrics Select Quality control and cause analysis on central segregation of round bloom Steelmaking    2013, 29 (2): 19-21.   Abstract （391）            Knowledge map    Save In casting two different sectional round bloom,namely Φ300 mm and Φ500 mm blooms simultaneously at a 5 strand round bloom caster in the Steelmaking Plant of Chengde Jianlong Special steel Co.,Ltd.,due to misalignment of the axis of coil of the electromagnetic stirrer with the centerline of the mold for small sectional round bloom,the greater the effect of segregation on the internal carbon segregation index of the bloom will be.By application of a series technological measures such as stable drawing speed,low overheat casting,optimization of slectromagnetic stirring and secondary cooling water distribution the carbon segregation index and equiaxel crystal macrostructure have been improved and they are completely up to the standard. Related Articles | Metrics Cited: Baidu(1) Select Causes and control research on the edge crack defect of hot-rolled strip Q235B Steelmaking    2013, 29 (2): 22-24,7.   Abstract （376）            Knowledge map    Save Inspection and analysis of the edge crack defect of hotrolled strip Q235B show that the main reason for the edge crack is mismatching of various processing parameters and supercooling of the slab corner at the juncture of the sudden fluctuation of casting speed in the process of fast changing the tundish.The transverse corner cracks taking place at the wave hollows of the oscillation marks further deteriorates and finally evolves into edge cracking defects.By adoption of the optimized continuous casting process the transverse corner cracks of the slab can be effectively reduced and the edge cracks of the hot rolled strip can be eliminated as well.In the meanwhile the edge crack defects can be avoided in rolling the trimmed slab by grinding the corner defect of the slab. Related Articles | Metrics Select Application practice of refining ZG06Cr13Ni4Mo steel for hydroturbine purpose by 120 t VOD process Steelmaking    2013, 29 (2): 25-29,3.   Abstract （361）            Knowledge map    Save According to the thermodynamic and kinetic theory of “decarbonization and chromium conservation” under vacuum condition some research has been done on the practice of refining ZG06Cr13Ni4Mo steel in a foundry plant of Shanghai.The results show that the critical value of carbon and endpoint of oxidation in the process of blow refining in a 120 t VOD can be precisely judged by observing the variation curve of the oxygen differential pressure electric potential measured with a solid oxygen concentration difference cell as well as variation of offgas temperature and thus effective control of “decarbonization and chromium conservation” under the vacuum condition can be realized. Related Articles | Metrics Select Analysis of factors affecting desulphurization efficiency of CaO based composite desulphurization agent Steelmaking    2013, 29 (2): 30-33.   Abstract （370）            Knowledge map    Save The present paper analyzes factors affecting the efficiency of desulphurization as well as the effects of lime quality, grain size of powder, charging amount, temperature and titanium content of the hot metal on desulphurization. The results of use in a specific steelmaking plant show that the desulphurizatin rate reaches 95.1 % and consumption of desulphurization powder is cut down to 13.5 kg/t from 17 kg/t as soon as w(CaO) takes up 90 % and powder with grain size less than 0.15 mm runs up to 96 % of the total hot metal. Related Articles | Metrics Select Prediction of oxyen blow rate in BP neural network based converter refining Steelmaking    2013, 29 (2): 34-37,4.   Abstract （423）            Knowledge map    Save In light of the dynamic blowing process of converter a BP neural network based prediction model is proposed for the purpose of determination of total blow oxygen and end blow oxygen in converter steelmaking.Critical influence factors for total blow oxygen and end blow oxygen prediction can be determined by correlation analysis.Fivenumber summary method is used to discriminate the data.BP neural network is improved by LM algorithm.Then,several neural network models with different topology structure are trained and compared with the history data,and the best network topology is selected.The performance of the best neural network model is evaluated.The results show that the hit rate to total blow oxygen predicted by model is 87.88 % with control precision among 800 m3,and the hit rate to end blow oxygen predicted by model is 91.99 % with control precision among 400 m3 respectively. Related Articles | Metrics Cited: Baidu(2) Select LF end-point temperature prediction of molten steel by GMDH neural Steelmaking    2013, 29 (2): 38-41.   Abstract （380）            Knowledge map    Save In light of the complexity of influencing factors of LF smelting endpoint temperature, the temperature prediction of molten steel is carried out by GMDH (Group Method of Data Handling) neural network with the selforganizing data mining principle as the core. The hit rate of temperature between ±5 ℃is 78.31 %. The hit rate of temperature between ±7.5 ℃is 92.77 %. The material thermal effect model is established.Through calculation of thermal effects of different materials charging into the molten steel, all materials added to the LF refining furnace are translated into an input factor. The temperature prediction of molten steel based on GMDH neural network is improved. The hit rate of temperature between ±5 ℃ reaches 88.72 % and the hit rate of temperature between ±7.5 ℃ is 98.44 %. The hit rate of temperature prediction based on GMDH neural network using material model is significantly increased and the temperature prediction has better adaptability for the changes of material structure caused by the smelting multiple steel. Related Articles | Metrics Select Prediction model of dissolved aluminum content in deoxidization process of RH refining Steelmaking    2013, 29 (2): 42-44.   Abstract （436）            Knowledge map    Save Based on productive performance of RH refining in Tangsteel,a predicting model of dissolved aluminum content in Al-killing stage has been constructed with multiple linear regression analysis.The results show that after decarbonization in RH the higher the dissolved oxygen content in the liquid steel the lower the dissolved aluminum in the liquid steel after deoxidation; properly high temperature of the liquid steel is favorable for increase of the dissolved aluminum content in the liquid steel; and with the increase of the aluminum addition into the liquid steel in hot metal deoxidation the dissolved aluminum in liquid steel grows up.The on-site measured value of the dissolved aluminum in liquid steel basically fluctuates around the predicted value.The model can successfully predict the dissolved aluminum in liquid steel after Alkilling in RH refining in Tangshan Steel Corporation of Hebei Iron & Steel Group and thus this newly developed model is credible. Related Articles | Metrics Select Analysis mineralogical phases of mold flux film from Tangsteel Steelmaking    2013, 29 (2): 45-48,5.   Abstract （395）            Knowledge map    Save The mold flux film collected from No.1 CC machine of the Plate Mill of Hebei Iron & Steel Group for casting steel grades Q345B and Q235B is observed and then the constituents of mineralogical phases of the film are analyzed by Xray diffraction and the microstructure of the slag film is observed by a polarizing microscope and micro mineralogical phase of the film and the stratification structure of the glass phase are analyzed and the effects of the chemical compositions of the mold flux on the formation of the mineralogical phase of the flux are checked and thus theoretical evidence is provided for development and application of the CC mold flux. Related Articles | Metrics Select Precipitation and ferrite nucleation stimulation of titanium containing inclusions in X120 pipeline steel Steelmaking    2013, 29 (2): 49-52,7.   Abstract （375）            Knowledge map    Save The precipitation conditions of titanium containing non-metallic inclusions in X120 pipeline steel are calculated with thermodynamics. In term of calculation of the target content of titanium in the pipeline steel X120 ( w(Ti)=0.015%), when w(Al)=0.000 35 %～0.003 30 % Al2O3·TiO2 is formed and when w(Al)>0.003 30 % Al2O3 occurs and pure MgO inclusion can be formed only if w(Mg) ＞1.62×1013,and composite inclusions 2MgO·TiO2 can be formed if w(Mg)=0.0008%. No pure MgO inclusions can be found in the X120 pipeline steel, in other word in the pipeline steel such a few deoxidation products as 2MgO·Ti2O3、MgO·A12O3、SiO2、A1203、Ti2O3、MnO may exist and they may mix with the sulphides to form the composite inclusions. The Results of observation by SEM are in coincidence with that of the thermodynamic calculation. The ferrite nucleation stimulated by Ti containing inclusions is observed by SEM and results show that Ti containing incusions in X120 pipeline steel possesses very strong ability to stimulate the nucleation of ferrite. Related Articles | Metrics Cited: Baidu(1) Select Analysis of the surface longitudinal crack of billet for 40Mn2 steel Steelmaking    2013, 29 (2): 53-56.   Abstract （339）            Knowledge map    Save Through macroscopic test, fracture analysis, tensile test, gas content measurement and other methods the present paper analyzes the cause of the surface longitudinal crack of 40Mn2 steel bloom. The result shows that the grain boundary strength is lowered by the high content of hydrogen and increase of stress on the surface of bloom arising from climate and other factors in the process of cooling leads to bloom crack along the coarse columnar crystals and then further expansion to the longitudinal cracks. Related Articles | Metrics Cited: Baidu(2) Select Effect of dynamic soft reduction model on the improvement in inner quality of slab Steelmaking    2013, 29 (2): 57-60.   Abstract （339）            Knowledge map    Save n order to solve the problem of poor inner quality of the continuous casting slab with 250 mm×1 600 mm cross section produced in Nanyang Hanye Special Steel Co.,Ltd., dynamic soft reduction control model is developed by the nail shooting test on the slab. After the model is put into the production of continuous casting slab, the parameters of dynamic secondary cooling and soft reduction can be adjusted according to different process conditions for different steel grades. The model can effectively reduce the center segregation in the slab and improve the inner quality of the slab. Therefore the conformity ratio of the rolled steel plates in ultrasonic detection test can be greatly upgraded by application of the model. Related Articles | Metrics Select Experimental research on effect of continuous casting cooling intensity on composition segregation and band microstructure of rolled steel Steelmaking    2013, 29 (2): 61-65.   Abstract （338）            Knowledge map    Save The effect of different cooling intensities in the secondary cooling zone on the band structure has been studied and analyzed by rolling the test steel CJ20CrMnTi in 200 mm×200 mm under the different cooling intensities and then analyzing the segregation of the test piece and inspecting and comparing the band structure of the rolled products. The result shows that:the average center carbon segregation index of slab decreases to 1.065 from 1.08 with increase of water ratio in secondary cooling zone, thus the composition segregation of the slab is effectively improved, the uniformity of structure of the rolled products raised and the control grade of the structure of the rolled products lowered to grade 1.5 below from grade 3.0 and the rolling efficiency is improved and the gas consumption reduced and the economic efficiency of the enterprise remarkably raised. Related Articles | Metrics Select Study on final solidification point of continuous casting Q345 Steel wide slab Steelmaking    2013, 29 (2): 66-70.   Abstract （417）            Knowledge map    Save A solidification heat transfer mathematical model of wide slab is established based on practical production conditions of Q345 steel wide slab in Echeng Steelmaking plant to determine final solidification point. Besides, it is tested and modified by pinshooting technique. The results show that the relative error between the results measured by pinshooting technique and the results calculated by solidification heat transfer mathematical model is within 1.3 %, so the results calculated by solidification heat transfer mathematical model can reflect final solidification point of Q345 steel wide slab truthfully. In typical speed of 1.15 m/min, the mushy zone of 200 mm thickness wide slab is 13.32~20.95 m far from mold liquid level. In typical speed of 0.95 m/min, the mushy zone of 250 mm thickness wide slab is 16.16~23.45 m far from mold liquid level. In typical speed of 0.80 m/min, the mushy zone of 300 mm thickness wide slab is 19.34~27.65 m far from mold liquid level. The final solidification point is very different at different casting speed and slab thickness. After continuous casting process optimization the qualified percentage for central segregation in Q345 steel wide slab within rating I increases from 85.4 % to 99.5 %. Related Articles | Metrics Cited: Baidu(1) Select Research on cyclic utilization of converter steelmaking dust in BOF Steelmaking    2013, 29 (2): 71-74.   Abstract （383）            Knowledge map    Save Based on the mechanism of slagging and temperature controlling in BOF steelmaking process, raw materials, such as sludge, dust ash and binders, are processed into dust pellets to replace the aluminum slagging agents for slag melting in the early smelting stage and to substitute the iron ore for temperature adjustment in the middle and late stage. It is found that compared with aluminum slagging agents and ores, when dust pellets are recycled in BOF steelmaking process, dephosphorization rate can reach 80.7 % and increase by 4.9 %. In addition, foaming and flowing properties of slag are very good, and the basicity of slag and iron loss are almost the same. Valuable resources, such as iron, can be recycled. At the same time, environmental pollution can be reduced, and steelmaking byproduct resources can be recycled in the steelmaking process. Related Articles | Metrics Cited: Baidu(1) Select Process and practice of “one ladle” technology Steelmaking    2013, 29 (2): 75-78.   Abstract （410）            Knowledge map    Save The present paper describes typical types and features of “One Ladle Supply Technology” in Steelmaking Shop. Meanwhile, it briefly introduces actual application of “One Ladle Supply Technology” in China and suggests general selection principles of “One Ladle Supply Technology”. Related Articles | Metrics Select Coldmodel simulation and application of slag splashing in 120 t topbottom combined blowing converter Steelmaking    2013, 29 (3): 1-5.   Abstract （291）            Knowledge map    Save Coldmodel simulation experiments on slag splashing in a 120 t top-bottom combined blowing converter were carried out. By measuring singer factors (e.g. topblowing gas flowrate, slag viscosity, lance height and slag amount), along with orthogonal test, the optimal parameters were obtained. The order of the factor that affect slag splashing was obtained through the range and variance analysis, which is topblowing gas flowrate > slag viscosity > lance height > slag amount. Finally, the optimized experimental program is that: lance height is 160 mm, topblowing gas flowrate is 51 m3/h, slag amount is 12 %, slag viscosity is 0.000 89 Pa·s，and the splashing density obtained is 23.07 g/(m2·s). It is applied in Tianjin Iron and Steel Group Co.,Ltd., and satisfied result is achieved. Related Articles | Metrics Select Optimization on metallurgical quality of martensite stainless steel Steelmaking    2013, 29 (3): 6-9,18.   Abstract （309）            Knowledge map    Save Based on theory of “decarburization and chromium yield” on smelting of stainless steel and process optimization in AOD refining, the globular oxide inclusion rating is below 2.0 and w(C)=0.02 %～0.04 %、w(Si)=0.49 %～0.53 %、w(Mn)=0.60 %～0.69 %、w(Cr)=12.90 %～13.57 %、w(Ni)=3.95 %～4.34 %、w(S)≤0.015 %、w(P)≤0.028 %、w(O)≤80×10-6、w(N)≤150×10-6、w(H)≤3×10-6 in the high quality steel can be obtained. New process significantly raised martensite stainless steel cleanliness, satisfy the smelting composition and various physical and chemical indicators. Related Articles | Metrics Cited: Baidu(4) page Page 1 of 3 Total 111 records First page Prev page Next page Last page