Volumn Content

Steelmaking 2014 Vol.30 Please wait a minute... For Selected: Download Citations EndNote Ris BibTeX Toggle Thumbnails Select Study on trial production of nitrogen microalloyed reinforced bar Steelmaking    2014, 30 (1): 1-5.   Abstract （275）            Knowledge map    Save The study on trial production of HRB400E using the new technique of nitrogen microalloying had been carried out. It was found that the billet had a thermoplastic brittle zone within the temperature range between 750 and 850 ℃. By controlling the continuous casting process, cast billet of highquality had been successfully produced. The final rebar had high tensile strength and suitable yield ratio as well as stable aging performance, and metallurgical structure showed that it consisted of ferrite and pearlite. Further analysis revealed that the improvement in the strength of newlydeveloped Nmicroalloyed rebar was mainly due to the precipitation of secondaryphase particles with diameter from 5 to 30 nm. This new technique of nitrogen microalloying could save the usage of vanadium element by approximately 40 % to 60 %. It made the cost of steel per ton decrease 4060 yuan and created obvious economic profits through adopting the production technology. Related Articles | Metrics Select Research and development of 25C2Ni4MoV steel for heavy fan main shaft 宋平;翟晓峰;潘宏涛 Steelmaking    2014, 30 (1): 6-9.   Abstract （343）            Knowledge map    Save For the strictly requirements on UT and no adopting the ESR production process，the smelting control difficulties of this steel grad had been analysis, and accordingly the key control points had been made. And the use of double vacuum process to produce 25Cr2Ni4MoV fan shaft steel had been also determined finally. The final steel product quality after testing had fully met the standard requirements on the chemical composition, mechanical properties, ultrasonic testing, and can completely replace the ESR steel. Related Articles | Metrics Cited: Baidu(1) Select Metallurgical effects of 120 t converter with less slag refining for decarburization and keep phosphorus Steelmaking    2014, 30 (1): 10-12.   Abstract （231）            Knowledge map    Save According to the characteristics of lowcarbon lowsulphur highphosphorus silicon steel, the process of deep desulfurization molten iron less slag smelting and decarbonization phosphorus conservation was used on 120 t converter in Ma’anshan Iron & Steel Company Ltd. The converter end point reached w(S)≤0.006 %, w(P)≥0.050 %, and the hit ratio of C-T was improved. The end molten steel oxygen activity was stability about 593×10-6. Blowing loss and splash were down, and molten steel yield was increased by 1.5 %. The mass of lime and other bulk material was controlled below 33.7kg/t, and the remarkable economic benefits were achieved. Related Articles | Metrics Cited: Baidu(1) Select Investigation of nonmetallic inclusions in titaniumkilled steel by a three stages deoxidization technology Steelmaking    2014, 30 (1): 13-16.   Abstract （201）            Knowledge map    Save By thermodynamics calculation and increasing oxygen content with Fe2O3 addition and deoxidization with titanium addition for three times, the morphology, dimensions and distribution of nonmetallic inclusions and microstructure of steel in titaniumkilled steel were investigated. The results showed that, increasing oxygen and deoxidation process three times, and controlling the oxygen content in steel greater than 0.001 %, oxygen and titanium can generate the titaniumcontaining oxide. Thermodynamic analysis proved that the titanium oxide was Ti2O3. After adding titanium in the steel the mass fraction of oxygen was about 0.002 %, and the number of titanium oxide below 2 μm increased and the number of titanium oxide between 2 μm to 3 μm changed little in the final sample. These inclusions could induce the precipitation of acicular ferrite through refine the organization. Related Articles | Metrics Select Optimization and improvement of 300 t converter skimming process in masteel Steelmaking    2014, 30 (1): 17-20.   Abstract （269）            Knowledge map    Save To reduce the slag outflow during converter’s taping，improve the quality of liquid steel, and increase the yield of alloy elements，the original pneumatic slagstopping process for 300 t converter was optimized by applying the skimming dart combined with the pneumatic slagstopping technology in No.4 SteelMaking and Rolling Plant General of Ma’anshan Iron and Steel Co., Ltd. Through the skimming dart technology, the successful slagstopping reached to 98 %, the quantity of slag outflow during taping was reduced by more than 30 %, and the average mass fraction of rephosphorization could be controlled under 0.003 %. Meanwhile, the yield of liquid steel was increased, the effect of slagsplashing and subsequent refining was improved. As a result, better economic benifits were gained. Related Articles | Metrics Select Elimination of 65 steel wire rod tensile rate of the production practice Steelmaking    2014, 30 (1): 21-23,2.   Abstract （194）            Knowledge map    Save This paper introduced the quality objection of cupcone fracture existed in 65 high carbon hard wire rod which was produced by Fujian Sanming Iron and Steel(Group) Co., Ltd. Minguang after July 2012. The reasons of quality objection were analyzed, and it was found that the main reason were alternate segregation position holes and center. Therefore, the process of the converter steelmaking, refining and continuous casting was optimized based on above analysis. The superheat of liquid steel and casting speed were the primary adjustment. Through the exploration and market feedback of the product quality, the measures were proved to be effective. The fracture phenomenon of 65 high carbon hard wire rod was eliminated, and the rate of dissent and claim of customers was correspondingly decreased. Related Articles | Metrics Select Investigation on decarburization process in 180 t RH degasser Steelmaking    2014, 30 (1): 24-28.   Abstract （194）            Knowledge map    Save Investigation on decarburization process in 180 t RH of Shasteel had been conducted, and the effect of initial condition of liquid steel, vacuum pressure,liftgas flowrate and oxygen blowing time on decarburization process had been explored. The experimental results indicated that there were three stages during the decarburization process: the decarburization rate constant was very low at the first and third stage, and the second stage was the major decarburization period with the largest decarburization rate constant. By decreasing the initial w(C)/w(O) ratio and the product of w(C)·w(O), the duration of the first stage would be shortened and the decarburization rate constant of the second stage would be increased. The decarburization rate constant would be increased when increasing the exhausting rate constant. If the time to reach the lowest pressure in chamber was less, the carbon content at decarburization end was lower. Blowing oxygen after mid period and increasing the liftgas flowrate from 113 m3 to 150 m3 after decarburization treatment for 7 minutes had no influence on decarburization process. Related Articles | Metrics Cited: Baidu(1) Select Investigation on nitrogen controlling techniques in IF steel Steelmaking    2014, 30 (1): 29-33.   Abstract （223）            Knowledge map    Save According to the practices of No.3 Steelmaking Work Area of General Steelmaking Plant of Ansteel, the effect of relevant factors on controlling nitrogen content in BOF, refining and continuous casting processes was studied, and nitrogen control technology of low nitrogen steel had been analyzed. The results indicated that increment of nitrogen mainly occurred during tapping process. By increasing hot metal ratio, controlling slag returning to dry, reducing reblowing times and time and feeding iron ore, the mass fraction of nitrogen could be reduced obviously to less than 12×10-6. Optimization of RH operation could improve the effect of advanced nitrogen removal. Shielded casting practice could control increment of nitrogen within 5×10-6. Related Articles | Metrics Select Experimental study on production of boron microalloying medium carbon steel Steelmaking    2014, 30 (1): 34-37,5.   Abstract （221）            Knowledge map    Save Mechanics characteristic and the mechanism of boron microalloying were revealed through the development and research of boron microalloyed medium carbon steel production process in Lianyuan Iron & Steel Co. converter→continuous casting process. The results showed that trace amounts of boron made grain coarsening behavior obviously, significantly reduced the yield strength of steel. It was not necessary to design special mold powder for boron microalloyed medium carbon steel, because boron had little effect on mold powder. The stable yielding rate of boron could be obtained through controlling Δw（N）<10×10-6, using ferromanganese, ferrosilicon to deoxidize, adding ferrotitanium at 3 minutes before calcium treatment, feeding boron line at 1 minutes before the calcium treatment in the process of refining, and the average yield was 78.8 %. First Ⅲ brittleness temperature region of medium carbon steel A36LB was among 700-900 ℃, the emergence of corner crack could be avoided through reducing of slab edge water and total water amount. Related Articles | Metrics Select Analysis of EAF melting technology with large proportion of direct reduction iron Steelmaking    2014, 30 (1): 38-40,4.   Abstract （182）            Knowledge map    Save The technology characteristic of EAF melting with large proportion of direct reduction iron were analyzed in one steelmaking plant in Middle East. And the real production indicated that EAF melting with large proportion of direct reduction iron should adopt large hot heel, continuous charging at top, 100 % direct reduction iron continuous melting, melting with foamed slag, bath stirring, which were benefit for organization and liquid steel quality. Related Articles | Metrics Select Research and application of new modifying technologyfor sulphur removal on liquid desulphurizing slag in hot metal Steelmaking    2014, 30 (1): 41-45.   Abstract （221）            Knowledge map    Save Because the liquid desulphurizing slag was difficult to skim, there was a high resulphurization in BOF during hot metal desulphurization using magnesium. To solve above problems, a new modifying technology of sulphur removal was put forward according improving reaction dynamic conditions between modifiers and liquid slags. The effect and influencing factors of original and new technologies were studied by hydraulic model experiment. The experiment results showed that: comparing with traditional technology, new modifying technology had excellent dynamic condition; the reaction area and the number of reaction modifiers were increased significantly. Furthermore, the industrial practice indicated that: the resulphurization in BOF from liquid desulphurizing slag decreased remarkably after new technology used which ensured the stable production of high valueadded low sulfur steel. Related Articles | Metrics Select Desulphurization analysis of slag with high basicity and prediction model for sulfur distribution ratio Steelmaking    2014, 30 (1): 46-50.   Abstract （235）            Knowledge map    Save To investigate the desulphurizing ability of slag with high basicity and high Mannesmann index for pipeline steel, industrial experiments had been carried out. The results showed that in the situation of a higher refining slag basicity and Mannesmann index than the recommended value, the addition of fluorites made the slag have a better fluidity, lower melting temperature and preferable desulphurizing ability. A comparatively accurate model for forecasting LS of pipeline steel was established by modifying the value calculated by KTH model. The ratio of that absolute error which was range of ±5 % reached 85 %. Related Articles | Metrics Select Experiment research and thermodynamics analysis on calcium treatment of pipeline steel L360QS Steelmaking    2014, 30 (1): 51-54,5.   Abstract （288）            Knowledge map    Save Thermodynamics analysis on calcium treatment process of pipeline steel L360QS was investigated by activity interaction coefficient and Bjorkvall method, and then calcium treatment experiment was also carried out. Thermodynamics analysis result shows that, when aluminum content in liquid steel is 0.045 %, w（Ca） and w（S） in molten steel should be respectively controlled about 0.003 321 % and below 0.002 563 % if we want to generate 12CaO&#8226;7Al2O3 inclusions and avoid CaS inclusions precipitation; calcium treatment experiment result demonstrates that CaS inclusions quantity increase with the increasement of calcium content in liquid steel, which decrease the inclusions containing spinel. In order to modify both oxide and sulphide inlusions completely, w（S） in molten steel should be controlled about 0.002 %, and w（Ca）should in the range of 0.003 5 %～0.004 0 %, as well as the w（T.Ca）/ w（S） should be above 1.9, Industrial trial results showed that the inclusions were modified, which achieve the desired effect completely. Related Articles | Metrics Select Study on process of RH desulfurization by powder injection Steelmaking    2014, 30 (1): 55-58.   Abstract （307）            Knowledge map    Save The principle of desulfurization by powder injection was analyzed in detail in this paper. Increasing the quantity of desulfurizer in liquid steel and prolonging the desulfurizer resistance time in liquid steel were proposed to increase RH desulfurization efficiency. And the work of optimizing RH powder injection lance height and driving gas flow rate in desulfurizing process by commercial tests were carried out. The results show that the optimal RH powder injection lance height was 1.3 m and the best driving gas flow rate in desulfurizing process was 50 m3/h. The optimized RH parameters could meet the requirements of producing and the mass fraction of sulfur in the steel could be controlled to be less than 15&#61645;10-6 steadily. Related Articles | Metrics Select Research on the surface cleanliness of IF steel slab Steelmaking    2014, 30 (1): 59-62.   Abstract （181）            Knowledge map    Save The surface inclusion of IF steel, including head, normal and end slab, was studied by original position analyzer for metal (OPA). The results show that: the distribution of the inclusion content and size in inner arc and outer arc are about the same. The inclusion content order in slabs is head slab > end slab > normal slab, the inclusion content in normal slab is steady. The inclusion content is fluctuated significantly in head and end slabs casted in unsteady state period, which decreases after 5.6 mm of the surface. With the distance from the surface of slab increasing, the average size of inclusion in slabs are smaller and smaller, and the same to the percentage of inclusion bigger than 5 μm. Related Articles | Metrics Select The simulation and transformation design of 250 t converter trunnion ring in No. 3 Steelmaking Plant of WISCO Steelmaking    2014, 30 (1): 63-66.   Abstract （241）            Knowledge map    Save The leakage accident of the 250 t converter trunnion ring in No.3 Steelmaking Plant of WISCO was described. The reasons which resulted in the leakage accident were analyzed. A 3-D model of the converter was established to analyze the stress distribution of what by FEM. And finally a transformation design was made. After transformation the leakage accident has been released radically. Related Articles | Metrics Select Design characteristics and production practices of 100 t EAF Steelmaking    2014, 30 (1): 67-70,7.   Abstract （216）            Knowledge map    Save The design concepts and features of 100 t domestic high impedance UHP EAF developed by CERI were introduced. The type of furnace was the conventional AC electric arc furnace with the eccentric bottom tapping style. Ultra high power technology, high impedance, hot metal charging technology, wall multi-cluster lance technology, flue gas waste heat recovery technology and other energy efficient technologies were integrated on the EAF. Production practice showed that the technical indicators of the electric arc furnace were excellent and the cost was the lowest on the condition of 65~75 t hot metal charging. Related Articles | Metrics Select Review of control of inclusions in stainless steel Steelmaking    2014, 30 (1): 71-78.   Abstract （294）            Knowledge map    Save A review of control of inclusions in stainless steel is made. It is analysed selection of deoxidizer influenced cleanliness of stainless steel. The formation condition of inclusions in Al-killed and Si-killed is pointed out. And the approaches to modify different kinds of inclusions to liquid ones are proposed. Oxide metallurgy in stainless steel gradually attracts more attention. It is hoped that properly controlling inclusions can reduce their harm to steel and improve product capabilities. Related Articles | Metrics Cited: Baidu(2) Select KR hot metal pretreatment production practice of 300 t BOF steelmaking system Steelmaking    2014, 30 (2): 1-5.   Abstract （238）            Knowledge map    Save Aimed at hot metal pretreatment process selection problem of 300 t BOF steelmaking system in Masteel, from the thermodynamic conditions，kinetic conditions，the desulfurization effect and cost,etc, combined with the existing raw material condition, opted for KR mixing method after comprehensive consideration. The devices of KR hot metal pretreatment came into use successfully and achieved good desulfurization effect. In production，successfully solves the mixing head life, iron losses, “blocking material”,etc influence production problems. And according to the hot metal conditions and the different requirements of different varieties to sulfur, formulated the different hot metal pretreatment desulphurization process. Full releases the capacity of KR hot metal pretreatment, greatly reduces the cost of production, building laid a solid foundation for low cost high efficiency of clean steel platform. Related Articles | Metrics Select Development and application of the process with the low cost slag-recycle steel-making of converter Steelmaking    2014, 30 (2): 6-8,13.   Abstract （209）            Knowledge map    Save Hansteel practices the process of recycle of the final slag of converter, which are sufficient using the final slag with the high basicity during the process, dumping the dephosphorization slag at the appropriate opportunity of the blowing and reforming the slag, thereby reducing the slag, the iron and steel material and the cost of the production. The lime consumption reduced by 29.3 %, the amount of the slagreduced by 32.8 %, the iron and steel material reduced by 5 kg/t after used the process, which has obtained excellent economic. Related Articles | Metrics Select Production practice of HRB400 steel by slag steel and slag iron with electric furnace Steelmaking    2014, 30 (2): 9-13.   Abstract （137）            Knowledge map    Save HRB400 steel production by metallurgical secondary resources such as slag steel and slag iron with “ETB electric furnace →LF → billet continuous casting” process was introduced. According to controlling the process parameters of ETB electric furnace and LF refining and billet continuous casting reasonably, it was achieved that the batch production of HRB400 steel meeting GB 1499.2—2007 and the effective utilization of the secondary resource. Related Articles | Metrics Cited: Baidu(1) Select Study and practice on smelting process of high toughness wind power flange steel Steelmaking    2014, 30 (2): 14-17.   Abstract （151）            Knowledge map    Save The present paper introduces experiments on production of high toughness wind power flange steel by EAF→LF→RH→CC process route at the special steel plant of Masteel，the experimental study determines main process condiction of high toughness wind power flange steel and control measures of the harmful elements by discussing in detail 4 key processing points of EAF smelting，LF refining，RH vacuum refining and continuous casting.The chemical compositions of the steel meet requirements，inclusions grade is low，all the mechanical performances meet the specification. The results provide scientific basis for future batch production. Related Articles | Metrics Select Control of surface sliver defect in hot-rolled SPHC strip Steelmaking    2014, 30 (2): 18-21,2.   Abstract （297）            Knowledge map    Save Morphology, distribution and chemical composition of surface sliver defect in hotrolled SPHC strip were investigated. The result shows that mold powder entrapment during continuous casting process is the key reason for the surface sliver defect. After the adjustment of steelmaking process, alumina inclusion was decreased, and the pourability of the molten steel was improved. In addition, with the modification of stopper argon flow rate and the viscosity of mould flux, mould level fluctuation was controlled in the range of ±3 mm, and the degrade ratio of the strip due to silver defects reduced from 15 % to 7 %. Related Articles | Metrics Cited: Baidu(5) Select Study on the causes and controlling of defects for cold-rolled sheet Steelmaking    2014, 30 (2): 22-25.   Abstract （226）            Knowledge map    Save The character and cause of surface defect on coldrolled sheet produced after continuous casting with high speed were studied by means of Aspex scanning electron microscope. The results shows that the surface defect is caused by Al2O3clusters, Ar+Al2O3 typed inclusions and the entrapped mold powder and the entrapped mold powder is the main part. After using FC mold in continuous casting with high speed and optimization the SEN, a followup occurrence rate of surface defect is from 3 % down to 1.5 %. Related Articles | Metrics Select Analysis and control of surface defects on IF steel for galvanized steel sheet Steelmaking    2014, 30 (2): 26-29.   Abstract （219）            Knowledge map    Save The surface defects and continuous casting process of IF steel for galvanized steel sheet of SGJT were analyzed. The results showed that the main reasons of the surface defects were the higher possibility of inclusions contents in the second slabs, nozzlechanged slabs and middle slabs. The surface defects were decreased remarkably through several measures such as steel remaining, refractory quality improving, cold steel removing in RH and tundish structure opitimizing. The product fraction defective caused by surface inclusions defects decreased to 2.59 %from 7.87 %. Related Articles | Metrics Cited: Baidu(1) Select Industrial experimental on dephosphorization pretreatmentin combined-blowing converter Steelmaking    2014, 30 (2): 30-34.   Abstract （188）            Knowledge map    Save Through field test on dephosphorization in 300 t combined-blowing converter of Shougang Jingtang Iron ＆ Steel United Co. Ltd., the effects of semi-steel temperature, slag oxidation, dephosphorization slag basicity as well as semisteel w(C)/w(P) on dephosphorization rate and phosphorus partition werestudied. The results showed that the finished mass fraction of phosphorus in semi-steel could be controlled less than 0.030 % under the condition of semisteel temperature and slag basicity controlled within 1 290-1 310 ℃ and 1.9-2.5 respectively, which could make the average mass fraction of phosphorus reach to 0.026 % in semisteel, and the rate of w(P)<0.030 % reach 81.01 %. The average phosphorus content and dephosphorization rate were improved obviously. Related Articles | Metrics Select Experiment of molten steel cleaning technology by finebubble method in killed carbon steel Steelmaking    2014, 30 (2): 35-37,4.   Abstract （176）            Knowledge map    Save This article introduce a removing inclusions process method by fine bubble coming from fine solid in molten steel, and the tests were proceeded in killed carbon steel in steel making plant. The results indicate that it may reduced markedly inclusions in the molten steel. Compared with conventional inclusion removal technology, the number of the oxide inclusion can be decreased to a lower level and the inclusion size becomes finer. Using this technology, the mass fraction of total oxygen in the ascast slab can approach to 0.000 7 %，and the purity of molten steel was improved. Related Articles | Metrics Select Inclusions control study of DC06 steel in 300 t ladle Steelmaking    2014, 30 (2): 38-43.   Abstract （220）            Knowledge map    Save According to various samples taken from steel and slag in ladle, the variations of inclusions in static steel and the efficiently absorptive conditions of inclusions in ladle slag were analyzed by using electrolytic method in nonaqueous solution and Factsage software. The results indicate that small inclusions collide into big inclusions and T.O levels decreases at the first 17 min of holding time, after 24 min inclusions aggregate into cluster inclusions and number of it reduces and the holding time should be remain at 28-33 min; the amount of Al2O3 dissolved when saturated is now 1.85 times of its original content if the slag basicity is stayed around 6.5-7.5，w(CaO)/w(Al2O3) of the slag is kept in 1.5-1.7, the mass fraction of SiO2 is stayed around 6 %-8 %, the mass fraction of MgO is kept less than 5 %. It could provide theoretical basis for reducing the content of macro inclusions. Related Articles | Metrics Cited: Baidu(2) Select Effect of nozzle bottom design on jet characteristics in continuous casting slab mold for high speed casting Steelmaking    2014, 30 (2): 44-48,5.   Abstract （181）            Knowledge map    Save A full scale water model was built to investigate the effect of bottom-design (mountain-, wave-, well-, flat-and round bottom) of submerged entry nozzles (SENs) on jet characteristics, backflow zone area and jet symmetry in continuous casting slab mold with propeller velocimeter and camera recording. The results show that the jet characteristic is stable for mountain- and wave-bottom SEN, however, shows a swirl flow for well-, flat- and round-bottom SEN with an alternative anticlockwise and clockwise rotating. The order of backflow zone area (BFZ) is: mountain-bottom>wave-bottom >well-bottom>flat-bottom>round-bottom, plant trial results show that the large backflow zone is one cause for nozzle clogging. Furthermore, the order of jet velocity asymmetry degree is similar to that order in high speed casting (steel throughput: 4.48 t/min). The spectrum powder analysis of jet velocity fluctuations show that the jet with mountain- and wave- bottom SEN have less turbulence but more kinetic energy than any other SENs, which result in larger backflow zone. While round bottom SEN has much turbulent yet less kinetic energy jet, which result in smaller backflow zone. Related Articles | Metrics Cited: Baidu(4) Select Research on the ultra-low-carbon steel with billet continuous casting process Steelmaking    2014, 30 (2): 49-52.   Abstract （208）            Knowledge map    Save The practice of ultra-low-carbon steel for billet continuous casting at Xingtai Iron & Steel CO., Ltd. is introduced. By comparing different refining process routes, an optimized process of “BOF→LF→RH→CC” is put forward. Studies have found that without ladle slag modifier, the mass fraction of (FeO)，(MnO) is high and volatile (9 %-14 %, 1 %-3 % respectively), result in flocculating flow. With three step slag modification process(topslag modification in BOF, LF and RH), the mass fraction of (FeO+MnO) can be controlled at about 3 %, which is favorable for calcium treatment to avoid flocculating flow, and continuous casting with more heats realized, the average mass fraction of carbon of finished product can be controlled at 0.008 % (BOF→RH→LF→CC process is 0.0102 %). Related Articles | Metrics Cited: Baidu(1) Select Cooling process of the third generation of automobile steelon the internal crack of continuous casting slabs Steelmaking    2014, 30 (2): 53-56.   Abstract （154）            Knowledge map    Save The continuous cooling transformation curve (CCT curve) was obtained by a Gleeble1500 hot simulator to investigate the cooling transformation of the third generation of automobile steel (TG steel). Steel ingots were produced by a vacuum induction furnace, and the internal quality and the microstructure of ingots produced under different cooling conditions were analyzed. The effect of cooling process on the microstructure and the internal crack of continuous casting slabs were researched to provide theoretical guidance for the improvement of internal crack in TG steel industry. Related Articles | Metrics Select Study on cleanliness of X80 pipeline steel Steelmaking    2014, 30 (2): 57-61,6.   Abstract （271）            Knowledge map    Save By the methods of metallographic observation, sampleelectrolyzing and scanning electron microscopy (SEM) analysis, the nonmetallic inclusions in X80 pipeline steel were investigated. The results showed that inclusions had a significant downward trend from LF inlet to microscopic in casting process with a fall of 77.77 %, the number of inclusions reduced most obviously in LF and RH refining process. The main types of inclusions in slab are CaO-CaS-Al2O3 composite inclusions, xCaO/xAl2O3 is less than 1.71of 12CaO·7Al2O3, inclusion modification effect is poorer. From converter end to casting process, the average total oxygen content had a downward trend. From LF inlet to the calcium treatment process finished, the average mass fraction of T.O decreased less than 3×10-6, the average mass fraction of T.O reduced 2.27×10-6 in RH refining process. It needs to improve the level of LF refining operation and RH refining operation stability. RH outbound to the slab was a process of increasing nitrogen, the mass fraction of nitrogen increased 2.27×10-6, protective casting level was higher. The large inclusions quantity was 1.46 mg/10 kg, inclusions are mainly spherical calcium aluminate inclusions, silicon aluminate inclusions and composite inclusions with magnesiaalumina spinel. Related Articles | Metrics Select Study on the grindability of steelmaking slag modified by silica Steelmaking    2014, 30 (2): 62-65.   Abstract （149）            Knowledge map    Save The modifier of silica was added to synthetic slag system of CaO-SiO2-MgO-Fe2O3 to study the change of grindability of slag. Experimental results indicate that, with addition amount of silica increasing, the content of dicalcium silicate in slag increases, calcium ferrite decreases, and the grindability of slag is enhanced. The results provide guidance for the utilization of converter slag in cement industry. Related Articles | Metrics Cited: Baidu(1) Select Influence of fluorite on viscosity and crystalline phase of concasting mold powder Steelmaking    2014, 30 (2): 66-69.   Abstract （162）            Knowledge map    Save The viscosity of the mold powder and the crystallization rates, mineral compositions of solidified slag samples were analyzed on the basis of the study in industrial mold powder and slag film. The result shows that: The mineral composition of in industrial mold powder are wollastonite, quartz, fluorite and sodium carbonate. The crystalline phase of flux film of nothing wrong on casting slab quality is melilite, and the crystallization rate is 90 %. With the content of fluorite being increased, the viscosity of the mold powder is reduced, and with the test temperature declined, the viscosity is elevated. The mineral composition of solidified slag are melilite, cuspidine and glassiness. With the content of fluorite being increased, the crystallization rates and the contents of cuspidine is increased, the content of melilite is reduced. Related Articles | Metrics Select Improvement of processing the data of level fluctuation at continuous casting mold Steelmaking    2014, 30 (2): 70-74.   Abstract （176）            Knowledge map    Save The original data of mold level measurement during continuous casting are not level fluctuation but level position varied with time. In the current study, the real level fluctuation were obtained by subtracting the smoothed value from the measured level position data. The effect of operation parameters of continuous casting on level fluctuation at the mold were discussed. Unsteady continuous casting resulted in greater fluctuation than steady state. With increased casting speed and larger mold width, the level fluctuation became more serious with larger amplitude. With 1.8 m/min casting speed, with FC-Mold electromagnetic brake the level fluctuation slightly decreased than that without FC-Mold. The fluctuation vertical velocity of mold level was obtained by perform derivative of the level fluctuation, which affected the entrapment of casting powder during continuous casting. Related Articles | Metrics Cited: Baidu(2) Select Design and optimization of 120 t RH refining feeding system Steelmaking    2014, 30 (2): 75-78.   Abstract （145）            Knowledge map    Save In this article the 120 t RH feeding system in Masteel Electric Furnace Plant was studied. The technological layout and the composition of feeding system， the problem of the RH feeding system which have put into production were summaried. And the design of the feeding system from four aspects as feeding time，weighing accuracy，unplanned feeding and vacuum rotary slide pipe were optimized. The good effect was achieved. The feeding system was put into production, the goal of energy saving and consumption reducing was achieved，and the design idea of RH feeding system was broadened. Related Articles | Metrics Select Research and application on dephosphorization pretreatment process in a single converter new doubleslag process Steelmaking    Accepted: 01 January 1900 Select Research and application on 65 steel smelting with duplex melting process in two converters Steelmaking    Accepted: 01 January 1900 Select Practice on low nitrogen controlling technology of Shougang Qiangang Steelmaking    Accepted: 01 January 1900 Select Research and application of slagadheringresistant spraying mix for gloryhole of converter Steelmaking    Accepted: 01 January 1900 page Page 1 of 3 Total 107 records First page Prev page Next page Last page