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Steelmaking 2023 Vol.39 Please wait a minute... For Selected: Download Citations EndNote Ris BibTeX Toggle Thumbnails Select Recent progress in oxide metallurgy technology by use of Ca，Zr and rare earth metals Steelmaking    2023, 39 (1): 1-16.   Abstract （125）      PDF（pc） （3846KB）（58）       Knowledge map    Save Related Articles | Metrics Select Physical simulation of mixing characteristics in 140 t hot metal ladle with argon bottom blowing Steelmaking    2023, 39 (1): 17-22.   Abstract （115）      PDF（pc） （1492KB）（33）       Knowledge map    Save Related Articles | Metrics Select Study on fluidity control of magnesium desulfurization slag after hot metal pretreatment Steelmaking    2023, 39 (1): 23-29.   Abstract （75）      PDF（pc） （1425KB）（24）       Knowledge map    Save Related Articles | Metrics Select Numerical simulation analysis of the feasibility of preheating scrap in the converter Steelmaking    2023, 39 (1): 30-34.   Abstract （64）      PDF（pc） （1270KB）（48）       Knowledge map    Save Related Articles | Metrics Select Simulation and application of lance with double Mach number on characteristics of supersonic oxygen jets in 210 t converter steelmaking Steelmaking    2023, 39 (1): 35-41.   Abstract （100）      PDF（pc） （1483KB）（25）       Knowledge map    Save Related Articles | Metrics Select Effect of basicity on the enrichment of phosphorus in BOF slag Steelmaking    2023, 39 (1): 42-46.   Abstract （51）      PDF（pc） （957KB）（24）       Knowledge map    Save Related Articles | Metrics Select Prediction model of oxygen supply in converter steelmaking based on ensemble learning Steelmaking    2023, 39 (1): 47-52.   Abstract （56）      PDF（pc） （1098KB）（23）       Knowledge map    Save Related Articles | Metrics Select Research and practice on longlife technology of ultrawide slab continuous caster mould Steelmaking    2023, 39 (1): 53-59.   Abstract （93）      PDF（pc） （1201KB）（24）       Knowledge map    Save Related Articles | Metrics Select Collision and aggregation among inclusions during the billet solidification in the continuous caster with electromagnetic soft-contact Steelmaking    2023, 39 (1): 60-67.   Abstract （99）      PDF（pc） （3421KB）（21）       Knowledge map    Save Related Articles | Metrics Select Erosion mechanism and improvement of MgO-C stopper nose Steelmaking    2023, 39 (1): 68-74.   Abstract （99）      PDF（pc） （4368KB）（46）       Knowledge map    Save Related Articles | Metrics Select Study on floater formation in continuous casting mold of high-titanium steel Steelmaking    2023, 39 (1): 75-82.   Abstract （95）      PDF（pc） （2616KB）（25）       Knowledge map    Save Related Articles | Metrics Select Effect of deoxidation process on inclusions in U20Mn2SiCrNiMo steel Steelmaking    2023, 39 (1): 83-88.   Abstract （82）      PDF（pc） （1578KB）（22）       Knowledge map    Save Related Articles | Metrics Select Effect of Mg treatment on secondary phase particles, microstructure and toughness in the HAZ of steel plate Steelmaking    2023, 39 (2): 1-17.   Abstract （106）      PDF（pc） （38913KB）（41）       Knowledge map    Save The effect of Mg treatment on secondary phase particles, microstructure and toughness in the HAZ of steel plate were reviewed, and the combined effect of w(Ti)/w(N), Al, Nb and B on microstructure and toughness of the Mg treatment steel plates were discussed. When the Mg mass fraction was 27×10-6, the volume fraction of IAF in HAZ had the highest value of 55.4 %, and the size of effective inclusions to promote the growth of IAF was concentrated at about 2 μm. With the increase of Mg content, TiN nanoparticles in steel were incrementally refined, and the value of the low-temperature impact toughness in HAZ zone increased linearly with the increase of the volume density of TiN nanoparticles. For ferritic shipbuilding steel plate, Mg treatment promoted the growth of intragranular acicular ferrite. After adding Mg mass fraction with 49×10-6, the impact toughness of the heat affected zone at -40 ℃ increased from 20 J to 167 J. For bainite marine engineering steel plate, after adding Mg mass fraction with 42×10-6, the secondary phase particle dissolution amount at high temperature became large, the pinning force decreased, and the grain size was coarsened. The toughness of HAZ at -40 ℃ decreased from 201 J with w(Mg)=2×10-6 to 58 J with w(Mg)=42×10-6. The optimum w(Ti)/w(N) was maintained at about 3.42. At this time, the number of precipitated particles in the secondary phase increases and the size decreased, which enhanced the pinning effect on grain boundaries. The addition of Al would reduce the HAZ toughness of the steel plate and the impact toughness at -20 ℃ was reduced from 201 J to 75 J when the Al mass fraction was 200×10-6. After adding Nb,the brittle structure in steel was increased. The HAZ impact toughness at -40 ℃ decreased from 127 J to 58 J after adding Nb mass fraction with 160×10-6 to Mg treatment steel plate. B would improve the hardenability of the steel, and the segregation at the grain boundary inhibits the formation of grain boundary ferrite. The impact toughness at -40 ℃ increased from 40 J to 141 J when 22×10-6 w(B) was added to the Mg treatment steel plate. Related Articles | Metrics Select Effect of Al2O3 content in refining slag on non-metallic inclusions in Al-killed steel Steelmaking    2023, 39 (2): 18-23.   Abstract （94）      PDF（pc） （6317KB）（140）       Knowledge map    Save In order to study the influence of Al2O3 content in medium-basicity refining slag on steel cleanness and inclusions, the equilibrium experiment between CaO-SiO2-Al2O3-MgO top slag with initial basicity of 4 and different Al2O3 content and Al-killed steel was carried out by MgO crucible at 1 873 K. The results show that after slag-steel reaction, the inclusion type changes from MgO-Al2O3-MnS to complex centered with MgO-Al2O3 and surrounded by MgO-Al2O3-SiO2-CaO(-MnO) system. The shape changes from block and cluster shape with angular boundary to near-spherical shape with smooth boundary. With the increase of Al2O3 content in slag, Al2O3 content in inclusions increases significantly, MgO content decreases, and other components have little change. The inclusion size tends to increase. The number density of inclusions increases which indicates that the cleanliness of steel deteriorates. Under present experimental conditions, when the Al2O3 mass fracton is about 20 %, the number density of inclusions is the lowest, and the steel cleanliness is the best. Based on the experimental results, thermodynamic analysis was done to discuss the composition change of slag and steel as well as the transformation of inclusions. Related Articles | Metrics Select Effect of oxygen content on liquid steel cleanliness after RH decarburization of IF steel Steelmaking    2023, 39 (2): 24-27.   Abstract （62）      PDF（pc） （5408KB）（126）       Knowledge map    Save Taking IF steel as the research object, combined with the production practice of 300 t RH furnace of Shougang Jingtang company, the oxygen content at the end of RH decarburization and the size and quantity of inclusions after deoxidation in the smelting process of IF steel were studied by means of production intensive sampling, data statistics, inclusion scanning electron microscope and other analysis methods. It was found that when the oxygen mass fraction after  RH decarburization was controlled at (290-310)×10-6, the Al2O3 inclusions produced in molten steel were the least. Based on this, the control method of oxygen content at the end of RH decarburization was studied. It was found that the hit rate of oxygen content at the end of decarburization in the forced decarburization mode was high and controllable, and the oxidation of top slag in the forced decarburization mode was weaker than that in the natural decarburization mode, which could reduce the formation of Al2O3 inclusions caused by secondary oxidation. The oxygen blowing calculation model was studied and established to ensure accurate control the oxygen content at the end of decarburization, which could improve the cleanliness of molten steel. Related Articles | Metrics Select Effect of the bottom blowing process on large-size inclusions in wind power steel during vacuum refining process Steelmaking    2023, 39 (2): 28-35.   Abstract （89）      PDF（pc） （7154KB）（52）       Knowledge map    Save In the current study, the optimization experiment of VD bottom blowing process for Q345D wind power steel was carried out to improve the removal efficiency of large-size inclusions in VD refining process. Before the VD vacuum treatment, inclusions in the steel were calcium aluminate with high Al2O3 content under the bottom blowing condition of 400 L/min in the first 10 min and 250 L/min in the last 5 min during VD high vacuum process (scheme 1), while the average composition of inclusions in the optimized process was closer to liquid calcium aluminate under the bottom blowing condition of 500 L/min in the first 10 min and 150-100 L/min in the last 5 min during VD high vacuum process (scheme 2 and scheme 3). Inclusions in the steel after VD treatment were all low melting point. For scheme 1, >10 μm and >15 μm inclusions increased by 66.24 % and 62.32 % respectively. However, >10 μm and >15 μm inclusions in scheme 2 increased by 23.40 % and 33.39 % respectively, especially the number density of inclusions increased by only 16.33 % and 28.57 % respectively. It was indicated that a strong stirring in the first 10 min and a moderate stirring in the last 5 min during VD high vacuum process could promote the removal of large-size inclusions and reduce the probability of slag entrainment. Related Articles | Metrics Select Investigation on the crust mechanism of tundish cover powder during continuous casting of ultra-low carbon steel Steelmaking    2023, 39 (2): 36-41.   Abstract （77）      PDF（pc） （5489KB）（100）       Knowledge map    Save The industrial trials and thermodynamic calculation were carried out to investigate the composition evolution, crystallization phase, and crust mechanism of tundish cover powder (TCP) during continuous casting of ultra-low carbon steel. The results showed that the ladle slag had a relatively strong oxidation capacity at RH departure and the w(CaO)/w(Al2O3) in the slag was low. The top slag of RH refining needs to be modified. Due to the slag carryover, mix of ladle filler sands and TCP, the composition of TCP during continuous casting has been significantly changed. Furthermore, the MgO·Al2O3 spinel in liquid phase was first formed and it promoted the nucleation and growth of 2CaO·Al2O3·SiO2 and CaO·TiO2 phases, resulting in the crust of TCP. To avoid the crust of TCP during continuous casting, the ladle carryover at cast end should be strictly controlled, and the  mass fraction of SiO2 and MgO in the original TCP are reduced to (10±2.5) % and 5.0 %～7.5 % respectively, which will inhibit the precipitation of 2CaO·Al2O3·SiO2  and MgO·Al2O3 spinel phases. Related Articles | Metrics Select Numerical simulation of the effect of tundish structure on steel fluid flow and inclusion removal Steelmaking    2023, 39 (2): 42-48.   Abstract （70）      PDF（pc） （12132KB）（76）       Knowledge map    Save A three-dimensional numerical model of a 72 t tundish in HBIS Group Tangsteel New District was established to investigate and compare the effect of different tundish structures on the steel level fluctuation, velocity distribution, residence time, and inclusion removal, including the turbulence inhibitor, weir and dam. The turbulence movement of the molten steel was calculated using the Realizable k-ε model. The residence time of molten steel was achieved by solving a concentration scalar equation (User-Defined Scalar, UDS), and the floating and removal of inclusions was obtained by solving the Discrete Phase Model (DPM). The results show that the level fluctuation near the upper nozzle of the tundish under the turbulence inhibitor with eaves and the opening turbulence inhibitor fluctuated greatly, which was about 3～4 times of that without the turbulence inhibitor. However, with the turbulence inhibitor with baffles, the molten steel formed a circulating flow between the baffles and the fluctuation of the liquid level was small, even smaller than the situation without the turbulence inhibitor. The moving distance of the molten steel in the tundish was increased when the weir and dam in the tundish existed at the same time, which was conducive to the floating and removal of inclusions. Under the current conditions, the average residence time of molten steel was longer and the removal rate of inclusions floating was higher when the weir and the dam were 1 060 mm and 2 000 mm from the width center of the tundish.  Related Articles | Metrics Select Steelmaking    2023, 39 (2): 49-55.   Abstract （57）      PDF（pc） （15496KB）（24）       Knowledge map    Save The floater in mould were analyzed by sampling the floater of mould and the molten steel in tundish during high silicon titanium stabilized austenitic stainless steel casting process. The results show that the inclusions in the floater of mould and tundish are both mainly pure TiN and TiN with MgO·Al2O3 as core. TiN inclusions are the cause of floater in mould. By combining both the experimental results and thermodynamic calculation, TiN inclusions would be formed at liquidus temperature of 1 455 ℃. As the mass fraction of nitrogen is less than 0.01 % in molten steel and the temperature in tundish is higher than 1 500 ℃,the floater cannot been found in mould. Related Articles | Metrics Select Modification of sulfide distribution in 46MnVS non-quenched and tempered steel by tellurium Steelmaking    2023, 39 (2): 56-61.   Abstract （78）      PDF（pc） （7365KB）（34）       Knowledge map    Save The sulfide in the industrial production of 46MnVS non-quenched and tempered steel slab containing tellurium was taken as the research object, combined with the inclusion three-dimensional etching and scanning electron microscope, the changes of sulfide equivalent diameter, quantitative density and three-dimensional morphology in the slab were observed and analyzed, and the influence of tellurium on sulfur segregation and sulfide distribution was summarized. It was found that the equivalent diameter of sulfide from quench layer to mixed crystal zone of tellurium modified slab  from 2.6 μm gradually increased to 5.8 μm. The effective diameter of sulfides in the central equiaxed zone first decreased and then increased, and the proportion of ellipsoidal and octahedral sulfides from edge to center gradually decreased from 84.2 % to 25.7 %. Compared with the unmodified slab, the sulfur segregation index decreased after tellurium modification,and the maximum sulfur segregation index decreased from 1.13 to 1.06. The equivalent diameter of sulfides decreased, the proportion of ellipsoidal and octahedral sulfides in the slab increased, and the proportion in the quench layer increased the most. Related Articles | Metrics Select Formation reason and control of craze cracks on the surface of 50 steel plate Steelmaking    2023, 39 (2): 62-67.   Abstract （86）      PDF（pc） （6516KB）（79）       Knowledge map    Save Aiming at the problem of serious surface craze cracks (incidence rate 7.92 %) of 50 steel plate rolled by 200 mm thick continuous casting slab, the morphology, distribution and composition of surface cracks were studied by means of scanning electron microscopy and spectral analysis. The results showed that surface cracks randomly appeared on the steel plate without fixed position in the width direction of the steel plate, and the crack depth was shallow, and the two sides of them showed the characteristics of high-brightness structure and oxidation dots. Spectral analysis showed that the carbon mass fraction at the crack was 0.2 %-0.3 % higher than that of the matrix, which showed that the slab of 50 steel was partially carbonized during the continuous casting process by mold flux with some carbon content. Subsequently, cracks and obvious high temperature oxidation characteristics were caused by uneven thermoplasticity of the slab during heating and rough rolling. According to the carburizing mechanism of continuous casting mold flux, the continuous casting process parameters such as mold slag line adjustment mode, casting speed, nozzle shape, mold flux composition, etc. were optimized, which effectively reduced the occurrence of local carburization on the surface of the continuous casting slab and cracking of the 50 steel plate. Related Articles | Metrics Select Research and application of surface crack control technology for microalloyed steel slab based on dual-phase transformation with controlled cooling Steelmaking    2023, 39 (2): 68-72.   Abstract （50）      PDF（pc） （13582KB）（21）       Knowledge map    Save One of the reasons for the occurrence of cracks on the surface of the slab is the low high-temperature plasticity caused by the coarse grains and grain boundary precipitation on the surface. In order to improve the slab plasticity, the high temperature confocal technology was used to research and develop the dual phase transformation control cooling technology for the slab surface structure.The grain size change and grain boundary precipitation state of steel grades under the dual-phase transformation controlled cooling process were studied by the Confocal Laser Scanning Microscope(CLSM), and the key technical parameters of the technology on the surface of the slab was put forward by simulation calculation. Through the transformation of cooling equipment, the requirements of dual-phase transformation controlled cooling technology was satisfied at the corner of the slab. In the field, peritectic steel was used to conduct industrial tests of steel grades. By analyzing the phase structure of the slab, it was found that the dual-phase transformation controlled cooling technology eliminated the grain boundary ferrite film and refined the surface grain size of the slab. The inspection results of slab corner scarfing also confirmed the effect of this technique on improving corner cracks for the peritectic steel. Related Articles | Metrics Select Wetting behavior of molten heavy rail steel and MgO based refractories Steelmaking    2023, 39 (2): 73-81.   Abstract （51）      PDF（pc） （10326KB）（34）       Knowledge map    Save The wettability measurement between MgO, MgAl2O4 and MgO-CaO refractories and the molten heavy rail steel was carried out using the sessile drop method at 1 550 ℃. The penetration of the molten steel to different refractories and the effect of different refractories on the steel cleanliness were analyzed using a scanning electron microscope after the wetting process. Results showed that the initial contact angels between MgO, MgAl2O4and MgO-CaO refractories and the molten heavy rail steel were 116.8°, 133.5° and 147.1°, while the equilibrium contact angles were 97.6°, 91.0°, and 109.4° at 1 550 ℃, respectively. The MgAl2O4 refractory was eroded by the heavy rail steel, leading to the formation of magnesium aluminum spinel inclusions on the surface of steel ball. Besides, the MgAl2O4 refractory was easily penetrated by the molten steel with the average penetration depth of 163.4 μm.A dense reaction layer was formed at the interface between MgO-CaO refractory and the molten steel. The reaction layer hindered the penetration of the molten steel into the MgO-CaO refractory, but the reactants were involved into the molten steel and spread out on the surface. The interaction between the molten steel and the MgO refractory was the weakest. MgO refractory hardly affected the steel cleanliness, and was weakly corroded by the molten heavy rail steel. Related Articles | Metrics Select Influence of rare earth addition time on composition and inclusions of heavy rail steel Steelmaking    2023, 39 (2): 82-88.   Abstract （52）      PDF（pc） （17905KB）（32）       Knowledge map    Save Industrial experimental research was carried out on the effect of adding rare earths at different times in the production process of “BOF→LF→VD→CC” for heavy rail steel. The rare earth content, inclusion size, number density and morphology in billet were analyzed. The results show that the yield of rare earth in the billet produced by adding rare earth after VD is 11.73 %, which is higher than that in the billet produced by adding rare earth after LF, which is 2.83 %. Combined with the analysis results of the oxygen content in the whole process, it shows that the rare earth participates in the deoxidation reaction after being added to the steel, and the reaction product floats up and removes. The addition of rare earth can effectively reduce the size of inclusions in the steel. Compared with the heavy rail steel without rare earth, in the heavy rail steel billet samples produced by adding rare earth after LF and after VD, the average length of inclusions decreases from 9.28 μm to 7.91 μm and 1.42 μm, respectively, and the average width decreases from 5.71 μm to 4.81 μm and 2.27 μm, respectively. The inclusion rating can be reduced, and the effect of reducing the inclusion rating of A, B, and D inclusions is obvious, and the inclusion rating of the heavy rail steel billet samples produced by adding rare earth after VD is better. By comparing the experiments of adding rare earths in different time, it is found that the process of adding rare earths after VD can improve the ability of heavy rail steel inclusions to modify. SEM and EDS analysis results show that rare earth mainly exists in Si-Ca-Mg-Al inclusions, which makes Si-Ca-Mg-Al inclusions change from water droplets to spherical, and the surface is enriched with sulfur. The analysis results of manganese sulfide inclusions show that, the process of adding rare earth after VD can make manganese sulfide and Si-Ca-Mg-Al inclusions coexist in steel, reducing the harm caused by manganese sulfide to steel. Related Articles | Metrics Select Progress on desulfurization and silicon content control technology of LF refining for low silicon steel Steelmaking    2023, 39 (3): 1-15.   Abstract （108）      PDF（pc） （16499KB）（82）       Knowledge map    Save Related Articles | Metrics Select Effect of sulfur content on oxidation behavior of CaS in KR desulfurization slag Steelmaking    2023, 39 (3): 16-24.   Abstract （95）      PDF（pc） （28038KB）（57）       Knowledge map    Save Related Articles | Metrics Select Effect of bottom blowing tuyeres arrangement on mixing of molten steel in a 120 t combined blowing converter Steelmaking    2023, 39 (3): 25-29.   Abstract （80）      PDF（pc） （3904KB）（50）       Knowledge map    Save Related Articles | Metrics Select The prediction model of endpoint phosphorus partition ratio in 100 t top and bottomblowing converter smelting IF steel Steelmaking    2023, 39 (3): 30-34.   Abstract （85）      PDF（pc） （4272KB）（62）       Knowledge map    Save Related Articles | Metrics Select Water modeling on the transport phenomenon during bottom gas injection of a 210 t ladle Steelmaking    2023, 39 (3): 35-43.   Abstract （64）      PDF（pc） （14111KB）（51）       Knowledge map    Save Related Articles | Metrics Select Nitrogen absorption control of molten steel in 120 t LF refining process Steelmaking    2023, 39 (3): 44-51.   Abstract （65）      PDF（pc） （8202KB）（82）       Knowledge map    Save Related Articles | Metrics Select Numerical simulation of inclusion removal in tundish with gas curtain Steelmaking    2023, 39 (3): 52-57.   Abstract （57）      PDF（pc） （7450KB）（31）       Knowledge map    Save Related Articles | Metrics Select Slab shell deformation behavior in ultrahigh speed thin slab continuous casting mold Steelmaking    2023, 39 (3): 58-65.   Abstract （76）      PDF（pc） （8067KB）（26）       Knowledge map    Save Related Articles | Metrics Select Analysis of influencing factors and countermeasures research for improving the precision of online roll gap control in segment Steelmaking    2023, 39 (3): 66-72.   Abstract （48）      PDF（pc） （7798KB）（25）       Knowledge map    Save Related Articles | Metrics Select Evolution and control of inclusions in BOFCCM of high manganese and high strength IF steel Steelmaking    2023, 39 (3): 73-78.   Abstract （72）      PDF（pc） （6178KB）（53）       Knowledge map    Save Related Articles | Metrics Select Influence of Ca content control on Ds inclusions in molten steel Steelmaking    2023, 39 (3): 79-85.   Abstract （83）      PDF（pc） （6351KB）（72）       Knowledge map    Save Related Articles | Metrics Select Effect of sulfur content on oxidation behavior of CaS in KR desulfurization slag Steelmaking    2023, 39 (3): 86-90.   Abstract （56）      PDF（pc） （5357KB）（63）       Knowledge map    Save Related Articles | Metrics Select Mechanism analysis and industrial practice of manganese sulfide inclusion control in steel Steelmaking    2023, 39 (4): 1-12.   Abstract （67）      PDF（pc） （9560KB）（64）       Knowledge map    Save The control of MnS inclusions in steel is a system engineering which involves multiple processes including smelting, solidification, heating and rolling, and requires multi-variable cooperative control. In this paper, the research status of MnS inclusions at home and abroad was discussed in detail, and the influence mechanism of different elements, heat treatment and rolling process on MnS inclusions were expounded. In addition, the current process control measures of MnS inclusions were summarized. The morphology, size and quantity of MnS inclusions can be effectively controlled by adopting appropriate deoxygenation process, improving the oxygen content at the solidification front, reducing the basicity of refining slag, adopting appropriate Ca treatment process, adopting low basicity tundish covering agent, increasing the secondary cooling water volume, strengthening cooling and reducing electromagnetic stirring intensity. In recent years, some new ideas have been proposed to control the deformation treatment and diffusion distribution of MnS inclusions. The morphology, size and quantity of MnS inclusions in steel can be effectively controlled by adding Mg, Ca-Mg, Zr, Ce and Te elements into molten steel. Related Articles | Metrics Select Effect of CaF2 and Al2O3 on performance of KR desulfurizer Steelmaking    2023, 39 (4): 13-20.   Abstract （46）      PDF（pc） （12361KB）（30）       Knowledge map    Save In order to reduce the content of harmful sulfur elements in steel, KR desulfurization method is widely used in steel enterprises to produce low sulfur steel, and the influence of desulfurizer on the desulfurization efficiency is especially critical. In this paper, the effect of components on liquidus temperature, sulfur capacity, desulfurizer consumption, melting point, viscosity and desulfurization rate of CaO-Al2O3-SiO2-CaF2-MgO slag system were analyzed, based on simplex lattice method, FactSage 8.1 thermodynamic software, hemispherical melting point meter, rotating viscometer and slag-metal experiment. It was concluded that, the liquidus temperature of desulfurizer increased with CaO addition, and decreased with CaF2 addition, while the sulfur capacity of desulfurizer increased with CaO and decreased with Al2O3 and CaF2 enhancement. Meanwhile, with CaF2 and Al2O3 addition, the desulfurizer consumption and melting point changed little in slag with low content of SiO2, while the consumption increased greatly and the melting point decreased obviously in slag with high content of SiO2. The desulfurization efficiency of desulfurizer with melting point of 1 400-1 424 ℃, w(SiO2) of 0-10 %, w(Al2O3) and w(CaF2) of 5 % -15 %, w(MgO) of 6 % was better than that of desulfurizer used in an enterprise, and the comprehensive desulfurization ability of CaF2was stronger than that of Al2O3. Combined with the high temperature viscosity, the desulfurization efficiency and the subsequent slagging-off process, No.2 desulfurizer was the best choice for KR desulfurization. Related Articles | Metrics Select Development of data driven prediction model for endpoint slag composition and slag splashing time of converter Steelmaking    2023, 39 (4): 21-27.   Abstract （46）      PDF（pc） （4987KB）（27）       Knowledge map    Save Based on the actual production data of 260 t converter, prediction models of the main components of endpoint slag,CaO, SiO2, TFe and MgO, were established through four algorithms of machine learning algorithm,XGBoost (eXtreme Gradient Boosting), elastic regression, linear regression and AdaBoost (Adaptive Boosting). By optimizing the parameters, the determination coefficients R2 of XGBoost endpoint slag composition prediction model is all above 0.8.The slag splashing time model was modeled using five algorithms: SVR (Support Vector Regression), LGBM (Light Gradient Boosting Machine), GBDT (Gradient Boosting Decision Tree), RF (Random Forest) and XGBoost, respectively. Then, the integrated slag splashing time model was obtained by integrating SVR, XGBoost and GBDT. Stacking integrated slag splashing time model improves the prediction effect of each single model, and the prediction hit rate is 89.95 % in the error range of ±20 s. Related Articles | Metrics Select Endpoint prediction of duplex process converter based on machine learning algorithm Steelmaking    2023, 39 (4): 28-36.   Abstract （56）      PDF（pc） （5876KB）（21）       Knowledge map    Save The establishment of accurate BOF endpoint prediction model is particularly important for the improvement of production efficiency and liquid steel cleanliness. This paper took the converter of Shougang Jingtang duplex process in converter process as the research object, Pearson correlation analysis was conducted on historical production data, and 15 independent variables most relevant to the endpoint temperature and carbon content of the converter were obtained. Three machine learning algorithms of BP neural network, limit learning machine (ELM) and support vector machine (SVM) were used to build the prediction model of converter endpoint. Then 160 sets of new sample data were selected to verify the prediction accuracy of the three models. The results show that the accuracy of the prediction model of the end-point temperature and carbon content of the converter under the SVM model is higher. The hit rate of the prediction error of the endpoint temperature within ±15 ℃ is 90.6 %, and the hit rate of the prediction error of the endpoint carbon mass fraction within ±0.01 % is 93.8 %. In addition, the prediction model of converter end point based on support vector machine algorithm shows that the hit rate of endpoint temperature within ±15 ℃ and carbon mass fraction within ±0.01 % of duplex process in converter process is 9.1 % and 14.4 % higher than that of the conventional process. 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