The gating system and the overflow system were designed according to the casting structure during high pressure die casting(HPDC) process. The simulation was carried out by ProCAST software to visualize the injection ...The gating system and the overflow system were designed according to the casting structure during high pressure die casting(HPDC) process. The simulation was carried out by ProCAST software to visualize the injection chamber pre-crystallization and the flow of molten metal. The main work is to research four die casting process parameters, i.e. injection temperature, low-pressure velocity, high-and low-pressure velocity’s switching position, and high-pressure velocity. Experimental results show that the higher injection temperature and lowpressure velocity can mitigate the pre-crystallization of the injection chamber. However, when the low-pressure velocity exceeds 0.2 m·s-1, the air entrapment in the chamber occurs. Besides, when the high-pressure velocity is greater than 2.5 m·s-1, the overflow channel at the final filling position is covered by the liquid metal too early. Finally, the injection temperature of 650 °C, the low-pressure velocity of 0.2 m·s-1, the high-and low-pressure velocity’s switching position of 320 mm and the high-pressure velocity of 2 m·s-1 are obtained as the optimal parameters by the software simulation, which has been verified by actual production.展开更多
Purpose–The precast concrete slab track(PST)has advantages of fewer maintenance frequencies,better smooth rides and structural stability,which has been widely applied in urban rail transit.Precise positioning of prec...Purpose–The precast concrete slab track(PST)has advantages of fewer maintenance frequencies,better smooth rides and structural stability,which has been widely applied in urban rail transit.Precise positioning of precast concrete slab(PCS)is vital for keeping the initial track regularity.However,the cast-in-place process of the self-compacting concrete(SCC)filling layer generally causes a large deformation of PCS due to the water-hammer effect of flowing SCC,even cracking of PCS.Currently,the buoyancy characteristic and influencing factors of PCS during the SCC casting process have not been thoroughly studied in urban rail transit.Design/methodology/approach–In this work,a Computational Fluid Dynamics(CFD)model is established to calculate the buoyancy of PCS caused by the flowing SCC.The main influencing factors,including the inlet speed and flowability of SCC,have been analyzed and discussed.A new structural optimization scheme has been proposed for PST to reduce the buoyancy caused by the flowing SCC.Findings–The simulation and field test results showed that the buoyancy and deformation of PCS decreased obviously after adopting the new scheme.Originality/value–The findings of this study can provide guidance for the control of the deformation of PCS during the SCC construction process.展开更多
Achieving optimal mechanical performance in high-pressure die-cast(HPDC)Mg-based alloys through experimental methods is both costly and time-intensive due to significant variations in composition.This study leverages ...Achieving optimal mechanical performance in high-pressure die-cast(HPDC)Mg-based alloys through experimental methods is both costly and time-intensive due to significant variations in composition.This study leverages machine learning(ML)techniques to accelerate the development of high-performance Mg-based alloys.Data on alloy composition and mechanical properties were collected from literature sources,focusing on HPDC Mg-based alloys.Six ML models—extra trees,CatBoost,k-nearest neighbors,random forest,gradient boosting,and decision tree—were trained to predict mechanical behavior.Cat Boost yielded the highest prediction accuracy with R^(2) scores of 0.95 for ultimate tensile strength(UTS)and 0.92 for yield strength(YS).Further validation using published datasets reaffirmed its reliability,demonstrating R^(2) values of 0.956(UTS)and 0.936(YS),MAE of 1%and 2.8%,and RMSE of 1%and 3.5%,respectively.Among these,the CatBoost model demonstrated the highest predictive accuracy,outperforming other ML techniques across multiple optimization metrics.展开更多
Accurate retrieval of casting 3D models is crucial for process reuse.Current methods primarily focus on shape similarity,neglecting process design features,which compromises reusability.In this study,a novel deep lear...Accurate retrieval of casting 3D models is crucial for process reuse.Current methods primarily focus on shape similarity,neglecting process design features,which compromises reusability.In this study,a novel deep learning retrieval method for process reuse was proposed,which integrates process design features into the retrieval of casting 3D models.This method leverages the comparative language-image pretraining(CLIP)model to extract shape features from the three views and sectional views of the casting model and combines them with process design features such as modulus,main wall thickness,symmetry,and length-to-height ratio to enhance process reusability.A database of 230 production casting models was established for model validation.Results indicate that incorporating process design features improves model accuracy by 6.09%,reaching 97.82%,and increases process similarity by 30.25%.The reusability of the process was further verified using the casting simulation software EasyCast.The results show that the process retrieved after integrating process design features produces the least shrinkage in the target model,demonstrating this method’s superior ability for process reuse.This approach does not require a large dataset for training and optimization,making it highly applicable to casting process design and related manufacturing processes.展开更多
Casting technology is a fundamental and irreplaceable method in advanced manufacturing.The design and optimization of casting processes are crucial for producing high-performance,complex metal components.Transitioning...Casting technology is a fundamental and irreplaceable method in advanced manufacturing.The design and optimization of casting processes are crucial for producing high-performance,complex metal components.Transitioning from traditional process design based on"experience+experiment"to an integrated,intelligent approach is essential for achieving precise control over microstructure and properties.This paper provides a comprehensive and systematic review of intelligent casting process design and optimization for the first time.First,it explores process design methods based on casting simulation and integrated computational materials engineering(ICME).It then examines the application of machine learning(ML)in process design,highlighting its efficiency and existing challenges,along with the development of integrated intelligent design platforms.Finally,future research directions are discussed to drive further advancements and sustainable development in intelligent casting design and optimization.展开更多
The modified precipitation theory was employed to directly predict the multi-variantε-carbide precipitation from thermodynamics and growing and ripening kinetics.Three distinct variants were identified:Variants 1 and...The modified precipitation theory was employed to directly predict the multi-variantε-carbide precipitation from thermodynamics and growing and ripening kinetics.Three distinct variants were identified:Variants 1 and 2 were the perpendicular plate-likeε-carbides,while the granularε-carbides were Variant 3.The particle sizes of Variants 1 and 2 were usually larger than those of Variant 3.The mean aspect ratios of Variants 1 and 2 were 4.96,4.62 and 4.35 larger than those(1.72,1.63 and 1.56)for the granularε-carbides when coiled at 140,200 and 250℃,respectively.Thermodynamic analysis indicated that Variants 1 and 2 are easier to nucleate than Variant 3.The growing kinetic analysis implied that the relative nucleation time and precipitation time for Variants 1 and 2 were about 8 and 5 orders of magnitude less than those for Variant 3,respectively.The ripening kinetics further displayed that the ripening rate was similar for Variants 1,2 and 3.In addition,the dislocation density has weak influence onε-carbide nucleation.These findings suggest that the precipitation thermodynamic and kinetic models could be extended to second phase precipitation in other materials systems.Besides,nano-scaleε-carbides,fine block size and nano-twins,as well as medium-density dislocations,jointly caused the optimal match between strength and total elongation when coiled at 140℃.展开更多
The microstructure in vacuum-assisted high-pressure die casting(HPDC) Mg-4Al-4RE(AE44) alloy was studied. Special attention was paid to the characteristics of defect bands and their formation mechanisms. Since double ...The microstructure in vacuum-assisted high-pressure die casting(HPDC) Mg-4Al-4RE(AE44) alloy was studied. Special attention was paid to the characteristics of defect bands and their formation mechanisms. Since double defect bands are commonly observed, the cross section of die cast samples is divided into five parts with different grain morphologies and size distributions. The inner defect band is much wider than the outer one. Both the defect bands are solute segregation bands, resulting in a higher area fraction of Al;RE;phase than that in the adjacent regions. No obvious aggregation of porosities is observed in the defect bands of AE44 alloy. This may be due to a narrow solidification temperature range of AE44 alloy and a large amount of latent heat released during the precipitation of intermetallic phases. The formation of the defect bands is related to the shear stress acting upon the partially solidified alloy, which can lead to collapse of the grain network. However, the generation mechanisms of shear stress in the outer and inner defect bands are quite different.展开更多
A newly developed Mg-4Zn-2La-3Y alloy with high strength was fabricated by high-pressure die casting method,and its microstructures were thoroughly studied using transmission electron microscopy.The results demonstrat...A newly developed Mg-4Zn-2La-3Y alloy with high strength was fabricated by high-pressure die casting method,and its microstructures were thoroughly studied using transmission electron microscopy.The results demonstrate that it owns fine grains and approximately highly interconnected intermetallic phase skeletons,and exhibits ultra-high strength at both room and high temperatures.Interestingly,the eutectic intermetallic skeleton of this alloys is consisted of numerous fine particles,which are mainly consisted of two intermetallic phases,namely W and Mg12RE.Multiple{101}twins and SFs were found in the Mg12RE phase while a few of SFs in the W phase.Additionally,minor long-period stacking ordered phase was observed in the eutectoid phase,and it probably nucleated on the Mg12RE phase following a certain OR as(0002)14H//(110)Mg12REand[1120]14H//[111]Mg12RE,or(0002)14H//(211)Mg12REand[1120]14H//[111]Mg12RE.This special intermetallic skeleton with many interfaces and planar faults can efficiently transfer dislocations across grain boundaries,and this is the key factor for the outstanding mechanical properties of the studied alloy.展开更多
To study the influence of roll casting process parameters on temperature and thermal-stress fields for the AZ31 magnesium alloy sheets,three-dimensional geometric and 3D finite element models for roll casting were est...To study the influence of roll casting process parameters on temperature and thermal-stress fields for the AZ31 magnesium alloy sheets,three-dimensional geometric and 3D finite element models for roll casting were established based on the symmetry of roll casting by ANSYS software.Meshing method and smart-sizing algorithm were used to divide finite element mesh in ANSYS software.A series of researches on the temperature and stress distributions during solidification process with different process parameters were done by 3D finite element method.The temperatures of both the liquid-solid two-phase zone and liquid phase zone were elevated with increasing pouring temperature.With the heat transfer coefficient increasing,the two-phase region for liquid-solid becomes smaller.With the pouring temperature increasing and the increase of casting speed,the length of two-phase zone rises.The optimized of process parameters（casting speed 2 m/min,pouring temperature 640 ℃ and heat transfer coefficient 15 kW/（m2·℃） with the water pouring at roller exit was used to produce magnesium alloy AZ31 sheet,and equiaxed grains with the average grain size of 50 μm were achieved after roll casting.The simulation results give better understanding of the temperature variation in phase transformation zone and the formation mechanism of hot cracks in plates during roll casting and help to design the optimized process parameters of roll casting for Mg alloy.展开更多
A new process for swirling flow generation in the submerged entry nozzle （SEN） in continuous casting process of steel was proposed. A rotating electromagnetic field was set up around the SEN to induce swirling flow ...A new process for swirling flow generation in the submerged entry nozzle （SEN） in continuous casting process of steel was proposed. A rotating electromagnetic field was set up around the SEN to induce swirling flow by Lorentz force. The flow and temperature fields in the SEN and round billet mold with electromagnetic swirling were numerically simulated and then verified by the electromagnetic swirling model experiment of low melting point alloy. The effects of divergent angle of the SEN on the flow and temperature fields in mold with electromagnetic swirling were investigated. The electromagnetic swirling flow generator （EMSFG） could effectively induce swirling flow of molten steel in the SEN, which consequently improved greatly the flow and temperature fields in the mold. Below the nozzle outlet in mold, with the increase of divergent angle, the stream of bulk flow diverged more widely, the high temperature zone shifted up, and the temperature field became more uniform. Above the nozzle outlet in mold, with 350 A electromagnetic swirling, when the divergent angle of the SEN increased, the upward flow velocity and the meniscus temperature first increased and then decreased. With a divergent angle of 60~, the upward flow velocity and meniscus temperature reaced the largest value.展开更多
In this study, the effect of melting temperature on the microstructural evolutions, behavior, and corrosion morphology of Hadfield steel in the casting process is investigated. The mold was prepared by the sodium sili...In this study, the effect of melting temperature on the microstructural evolutions, behavior, and corrosion morphology of Hadfield steel in the casting process is investigated. The mold was prepared by the sodium silicate/CO_2 method, using a blind riser, and then the desired molten steel was obtained using a coreless induction furnace. The casting was performed at melting temperatures of 1350, 1400, 1450, and 1500°C, and the cast blocks were immediately quenched in water. Optical microscopy was used to analyze the microstructure, and scanning electron microscopy(SEM) and X-ray diffractrometry(XRD) were used to analyze the corrosion morphology and phase formation in the microstructure, respectively. The corrosion behavior of the samples was analyzed using a potentiodynamic polarization test and electrochemical impedance spectroscopy(EIS) in 3.5 wt% NaCl. The optical microscopy observations and XRD patterns show that the increase in melting temperature led to a decrease of carbides and an increase in the austenite grain size in the Hadfield steel microstructure. The corrosion tests results show that with increasing melting temperature in the casting process, Hadfield steel shows a higher corrosion resistance. The SEM images of the corrosion morphologies show that the reduction of melting temperature in the Hadfield steel casting process induced micro-galvanic corrosion conditions.展开更多
The models, algorithms and implementation results of a computerized scheduling system were introduced for the steelmaking-continuous casting process （SCCP） of a steel plant in China. The scheduling of SCCP in this p...The models, algorithms and implementation results of a computerized scheduling system were introduced for the steelmaking-continuous casting process （SCCP） of a steel plant in China. The scheduling of SCCP in this plant required that each cast plan should be processed on time, the charges in the same cast should be processed con- tinuously on the same caster, and the waiting time of the charges which are in front of each caster cannot exceed the given threshold. At the same time, the processing time of charges cannot be conflicted mutually in the same convert- ers or refining furnaces. Based on the research background, a hybrid optimal scheduling approach and its application were discussed. Aiming at the main equipment scheduling, an optimal scheduling method was proposed which con- sisted of equipment assignment algorithm based on dynamic program （DP） technique and conflict elimination algo rithm based on linear program （LP） technique. The approach guarantees that the charges are continuously processed on the same caster. Meanwhile, the requirement for high temperature ladle can also be satisfied due to the ladle matching function. Numerical results demonstrate solution quality, computational efficiency, and values of the mod els and algorithm.展开更多
High pressure die casting (HPDC) is a versatile material processing method for mass-production of metal parts with complex geometries,and this method has been widely used in manufacturing various products of excellent...High pressure die casting (HPDC) is a versatile material processing method for mass-production of metal parts with complex geometries,and this method has been widely used in manufacturing various products of excellent dimensional accuracy and productivity. In order to ensure the quality of the components,a number of variables need to be properly set. A novel methodology for high pressure die casting process optimization was developed,validated and applied to selection of optimal parameters,which incorporate design of experiment (DOE),Gaussian process (GP) regression technique and genetic algorithms (GA). This new approach was applied to process optimization for cast magnesium alloy notebook shell. After being trained,using data generated by PROCAST (FEM-based simulation software),the GP model approximated well with the simulation by extracting useful information from the simulation results. With the help of MATLAB,the GP/GA based approach has achieved the optimum solution of die casting process condition settings.展开更多
A grain-oriented silicon steel strip with AlN as main inhibitor was produced by thin slab casting and rolling（TSCR）process.The microstructure,texture and precipitates of the hot-rolled strip were investigated by use...A grain-oriented silicon steel strip with AlN as main inhibitor was produced by thin slab casting and rolling（TSCR）process.The microstructure,texture and precipitates of the hot-rolled strip were investigated by use of optical microscope（OM）,X-ray diffractometer,transmission electron microscope（TEM）and energy dispersive spectroscope（EDS）.The result shows that the microstructure and texture exhibit a through-thickness gradient similar to that of the hot-rolled strip produced by conventional high-temperature slab-reheating process;the preferred orientation varies from {110}〈001〉in the surface layer to{001}〈110〉in the center layer,and the Goss texture with a maximum intensity mainly concentrates on the surface layer.In addition,some other texture components,for example rotated Goss texture,form in the 1/4thickness layer,which are not observed in the hotrolled strip produced by conventional high-temperature slab-reheating process.The precipitates in the hot-rolled strip are mainly（Mn,Cu）S and AlN compound particles with dimension of 100-200 nm,and the fine precipitates are significantly less than that in the hot-rolled strip produced by conventional high-temperature slab-reheating process.Moreover,the areal density of the fine precipitates in the center layer is more than that in the surface layer.展开更多
Numerical simulation of casting＇s mold filling process is the main and the most important aspect of the foundry CAE technology. But it is time-consuming; it may take dozens of hours or several days. While with the de...Numerical simulation of casting＇s mold filling process is the main and the most important aspect of the foundry CAE technology. But it is time-consuming; it may take dozens of hours or several days. While with the development of computer hardware, numerical simulation of casting＇ s mold filling process has made rapid progress. The simulation results, therefore, have become more and more practical. This study tries to find some clues of the computational time of mold filling process. Firstly, this paper introduces mathematic model and the basic route of numerical simulation of casting＇s mold filling process. Then the computational time of mold filling process has been carefully studied, and some new and useful results have been gained from the study of the computational time. Finally, this paper has given some real applications of numerical simulation of casting＇s mold filling process.展开更多
Liners in wet ball mill for mineral processing industry must bear abrasive wear and corrosive wear, and consequently, the service life of the liner made from traditional materials, such as Hadfield steel and alloyed s...Liners in wet ball mill for mineral processing industry must bear abrasive wear and corrosive wear, and consequently, the service life of the liner made from traditional materials, such as Hadfield steel and alloyed steels, is typically less than ten months. Bimetal liner, made from high Cr white cast iron and carbon steel, has been successfully developed by using liquid-liquid composite lost foam casting process. The microstructure and interface of the composite were analyzed using optical microscope, SEM, EDX and XRD. Micrographs indicate that the boundary of bimetal combination regions is staggered like dogtooth, two liquid metals are not mixed, and the interface presents excellent metallurgical bonding state. After heat treatment, the composite liner specimens have shown excellent properties, including hardness 〉 61 HRC, fracture toughness ak 〉16.5 J.cm2 and bending strength 〉1,600 MPa. Wear comparison was made between the bimetal composite liner and alloyed steel liner in an industrial hematite ball mill of WISCO, and the results of eight-month test in wet grinding environment have proved that the service life of the bimetal composite liner is three times as long as that of the alloyed steel liner.展开更多
The numerical simulation technique was applied to the casting process of a valve-type part. The mold-filling and solidification stages of the casting were numerically analyzed. The filling behavior, solidification seq...The numerical simulation technique was applied to the casting process of a valve-type part. The mold-filling and solidification stages of the casting were numerically analyzed. The filling behavior, solidification sequence, and thermal stress distribution were reproduced and the possible defects, such as cold shut and shrinkage, were predicted. Based on the simulation result, the double-gating system was replaced by a single-gating system. Meanwhile, the chills were used to regulate the solidification sequence of casting. To eliminate the cracks in the casting, the sand core was converted into a canulate one. By modifying the original process, the defects were eliminated and the casting with good quality was obtained.展开更多
3-Dvelocity and temperature fields of mold filling and solidification processes of large-sized castingswere calculated,and the efficiency and accuracy of numerical calculation were studied.The mold filling andsolidifi...3-Dvelocity and temperature fields of mold filling and solidification processes of large-sized castingswere calculated,and the efficiency and accuracy of numerical calculation were studied.The mold filling andsolidification processes of large-sized stainless steel,iron and aluminum alloy castings were simulated by using ofnew scheme;their casting processes were optimized,and then applied to produce castings.展开更多
The characterization of multiple iron-rich phases in high-pressure die-cast AlSi10MnMg alloy was studied.Attention was focused on the formation and fracture behavior of the primary iron-rich phase((P-IMC)_(I))formed i...The characterization of multiple iron-rich phases in high-pressure die-cast AlSi10MnMg alloy was studied.Attention was focused on the formation and fracture behavior of the primary iron-rich phase((P-IMC)_(I))formed in the shot sleeve and plate-shaped eutectic iron-rich phase in high-pressure die cast(HPDC)AlSi10MnMg alloy.Results show that multiple types of iron-rich phases with various morphologies,in-cluding primary iron-rich phases(polyhedral(P-IMC)_(I) and(P-IMC)_(II))and eutectic iron-rich phases(plate-shaped,net shape,and fish-bone shape),were found in HPDC AlSi10MnMg.Coarse(P-IMC)_(I) formed in the shot sleeve were distributed in the interface between primaryα-Al and binary Al-Si eutectic.Small size(P-IMC)_(II) and various eutectic iron-rich phases formed in the die cavity and they were distributed in Al-Si binary eutectic.The primary iron-rich phases belonged to a simple cubic crystal structure with a lattice constant a=1.265 nm and they exhibited a lateral growth characteristic with a termination of{110}surface.βphase was surrounded byδphase and they coexisted in a plate-shaped iron-rich phase.High-density stacking fault inβphase andδ/βinterface provided an excellent nucleation site forδphase.From mechanical behavior,the stress concentration caused by eutectic iron-rich phases was far less than(P-IMC)_(I) and it would not cause crack initiation along the eutectic cluster boundary.In addition,(P-IMC)_(I) showed the worst deformation coordination with primaryα-Al while the plate-shaped eutectic iron-rich phase exhibited similar deformation characteristics with silicon particles.展开更多
Sliding gate control system is widely employed in continuous casting process of steel to control flow rate of molten steel.As molten steel passes through a sliding gate,uneven flow develops.This will cause asymmetrica...Sliding gate control system is widely employed in continuous casting process of steel to control flow rate of molten steel.As molten steel passes through a sliding gate,uneven flow develops.This will cause asymmetrical distribution of flow and temperature field in mold consequently,formation of vortex near the nozzle and entrapment of CC powder into the molten steel.etc,which have negative effect on process productivity and product quality.To suppress the uneven flow,electromagnetic swirling flow has been proposed to impose on the flow in submerged entry nozzle below the sliding gate.In this study the uneven flow developed by incompletely open sliding gate and the suppression of this uneven flow using electromagnetic swirling flow are numerically studied in round billet continuous casting of steel process.The improvement of the flow and temperature filed in the submerged entry nozzle and mold are investigated.It is found that:The uneven velocity in nozzle can be suppressed by electromagnetic swirling flow,and the flow and temperature field in mold be improved obviously;With the increase of electromagnetic swirling intensity,the effect of uneven flow can be almost completely suppressed.展开更多
基金financially supported by the National Key Research and Development Program of China(No.2016YFB0301003)
文摘The gating system and the overflow system were designed according to the casting structure during high pressure die casting(HPDC) process. The simulation was carried out by ProCAST software to visualize the injection chamber pre-crystallization and the flow of molten metal. The main work is to research four die casting process parameters, i.e. injection temperature, low-pressure velocity, high-and low-pressure velocity’s switching position, and high-pressure velocity. Experimental results show that the higher injection temperature and lowpressure velocity can mitigate the pre-crystallization of the injection chamber. However, when the low-pressure velocity exceeds 0.2 m·s-1, the air entrapment in the chamber occurs. Besides, when the high-pressure velocity is greater than 2.5 m·s-1, the overflow channel at the final filling position is covered by the liquid metal too early. Finally, the injection temperature of 650 °C, the low-pressure velocity of 0.2 m·s-1, the high-and low-pressure velocity’s switching position of 320 mm and the high-pressure velocity of 2 m·s-1 are obtained as the optimal parameters by the software simulation, which has been verified by actual production.
文摘Purpose–The precast concrete slab track(PST)has advantages of fewer maintenance frequencies,better smooth rides and structural stability,which has been widely applied in urban rail transit.Precise positioning of precast concrete slab(PCS)is vital for keeping the initial track regularity.However,the cast-in-place process of the self-compacting concrete(SCC)filling layer generally causes a large deformation of PCS due to the water-hammer effect of flowing SCC,even cracking of PCS.Currently,the buoyancy characteristic and influencing factors of PCS during the SCC casting process have not been thoroughly studied in urban rail transit.Design/methodology/approach–In this work,a Computational Fluid Dynamics(CFD)model is established to calculate the buoyancy of PCS caused by the flowing SCC.The main influencing factors,including the inlet speed and flowability of SCC,have been analyzed and discussed.A new structural optimization scheme has been proposed for PST to reduce the buoyancy caused by the flowing SCC.Findings–The simulation and field test results showed that the buoyancy and deformation of PCS decreased obviously after adopting the new scheme.Originality/value–The findings of this study can provide guidance for the control of the deformation of PCS during the SCC construction process.
基金supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2021R1A6A1A10044950)。
文摘Achieving optimal mechanical performance in high-pressure die-cast(HPDC)Mg-based alloys through experimental methods is both costly and time-intensive due to significant variations in composition.This study leverages machine learning(ML)techniques to accelerate the development of high-performance Mg-based alloys.Data on alloy composition and mechanical properties were collected from literature sources,focusing on HPDC Mg-based alloys.Six ML models—extra trees,CatBoost,k-nearest neighbors,random forest,gradient boosting,and decision tree—were trained to predict mechanical behavior.Cat Boost yielded the highest prediction accuracy with R^(2) scores of 0.95 for ultimate tensile strength(UTS)and 0.92 for yield strength(YS).Further validation using published datasets reaffirmed its reliability,demonstrating R^(2) values of 0.956(UTS)and 0.936(YS),MAE of 1%and 2.8%,and RMSE of 1%and 3.5%,respectively.Among these,the CatBoost model demonstrated the highest predictive accuracy,outperforming other ML techniques across multiple optimization metrics.
基金supported by the National Natural Science Foundation of China(Nos.52074246,52275390,52375394)the National Defense Basic Scientific Research Program of China(No.JCKY2020408B002)the Key R&D Program of Shanxi Province(No.202102050201011).
文摘Accurate retrieval of casting 3D models is crucial for process reuse.Current methods primarily focus on shape similarity,neglecting process design features,which compromises reusability.In this study,a novel deep learning retrieval method for process reuse was proposed,which integrates process design features into the retrieval of casting 3D models.This method leverages the comparative language-image pretraining(CLIP)model to extract shape features from the three views and sectional views of the casting model and combines them with process design features such as modulus,main wall thickness,symmetry,and length-to-height ratio to enhance process reusability.A database of 230 production casting models was established for model validation.Results indicate that incorporating process design features improves model accuracy by 6.09%,reaching 97.82%,and increases process similarity by 30.25%.The reusability of the process was further verified using the casting simulation software EasyCast.The results show that the process retrieved after integrating process design features produces the least shrinkage in the target model,demonstrating this method’s superior ability for process reuse.This approach does not require a large dataset for training and optimization,making it highly applicable to casting process design and related manufacturing processes.
基金supported by the National Natural Science Foundation of China(No.52074246)the National Defense Basic Scientific Research Program of China(No.JCKY2020408B002)+1 种基金the Key R&D Program of Shanxi Province(No.202102050201011)the Shanxi Province Graduate Innovation Project(No.2021Y591).
文摘Casting technology is a fundamental and irreplaceable method in advanced manufacturing.The design and optimization of casting processes are crucial for producing high-performance,complex metal components.Transitioning from traditional process design based on"experience+experiment"to an integrated,intelligent approach is essential for achieving precise control over microstructure and properties.This paper provides a comprehensive and systematic review of intelligent casting process design and optimization for the first time.First,it explores process design methods based on casting simulation and integrated computational materials engineering(ICME).It then examines the application of machine learning(ML)in process design,highlighting its efficiency and existing challenges,along with the development of integrated intelligent design platforms.Finally,future research directions are discussed to drive further advancements and sustainable development in intelligent casting design and optimization.
基金supported by the National Natural Science Foundation of China(No.52293395)National Key R&D Program of China(No.2021YFB3702403).
文摘The modified precipitation theory was employed to directly predict the multi-variantε-carbide precipitation from thermodynamics and growing and ripening kinetics.Three distinct variants were identified:Variants 1 and 2 were the perpendicular plate-likeε-carbides,while the granularε-carbides were Variant 3.The particle sizes of Variants 1 and 2 were usually larger than those of Variant 3.The mean aspect ratios of Variants 1 and 2 were 4.96,4.62 and 4.35 larger than those(1.72,1.63 and 1.56)for the granularε-carbides when coiled at 140,200 and 250℃,respectively.Thermodynamic analysis indicated that Variants 1 and 2 are easier to nucleate than Variant 3.The growing kinetic analysis implied that the relative nucleation time and precipitation time for Variants 1 and 2 were about 8 and 5 orders of magnitude less than those for Variant 3,respectively.The ripening kinetics further displayed that the ripening rate was similar for Variants 1,2 and 3.In addition,the dislocation density has weak influence onε-carbide nucleation.These findings suggest that the precipitation thermodynamic and kinetic models could be extended to second phase precipitation in other materials systems.Besides,nano-scaleε-carbides,fine block size and nano-twins,as well as medium-density dislocations,jointly caused the optimal match between strength and total elongation when coiled at 140℃.
基金the financial supports from the the National Natural Science Foundation of China (No. 51805389)the Natural Science Foundation of Hubei Province, China (No. 2018CFB210)the “111” Project, China (No. B17034)
文摘The microstructure in vacuum-assisted high-pressure die casting(HPDC) Mg-4Al-4RE(AE44) alloy was studied. Special attention was paid to the characteristics of defect bands and their formation mechanisms. Since double defect bands are commonly observed, the cross section of die cast samples is divided into five parts with different grain morphologies and size distributions. The inner defect band is much wider than the outer one. Both the defect bands are solute segregation bands, resulting in a higher area fraction of Al;RE;phase than that in the adjacent regions. No obvious aggregation of porosities is observed in the defect bands of AE44 alloy. This may be due to a narrow solidification temperature range of AE44 alloy and a large amount of latent heat released during the precipitation of intermetallic phases. The formation of the defect bands is related to the shear stress acting upon the partially solidified alloy, which can lead to collapse of the grain network. However, the generation mechanisms of shear stress in the outer and inner defect bands are quite different.
基金supported by the National Natural Science Foundation of China under grants no.51701200 and 51871069the Scientific and Technological Developing Scheme of Jilin Province under grants no.20200801048GH。
文摘A newly developed Mg-4Zn-2La-3Y alloy with high strength was fabricated by high-pressure die casting method,and its microstructures were thoroughly studied using transmission electron microscopy.The results demonstrate that it owns fine grains and approximately highly interconnected intermetallic phase skeletons,and exhibits ultra-high strength at both room and high temperatures.Interestingly,the eutectic intermetallic skeleton of this alloys is consisted of numerous fine particles,which are mainly consisted of two intermetallic phases,namely W and Mg12RE.Multiple{101}twins and SFs were found in the Mg12RE phase while a few of SFs in the W phase.Additionally,minor long-period stacking ordered phase was observed in the eutectoid phase,and it probably nucleated on the Mg12RE phase following a certain OR as(0002)14H//(110)Mg12REand[1120]14H//[111]Mg12RE,or(0002)14H//(211)Mg12REand[1120]14H//[111]Mg12RE.This special intermetallic skeleton with many interfaces and planar faults can efficiently transfer dislocations across grain boundaries,and this is the key factor for the outstanding mechanical properties of the studied alloy.
基金Project(CSTC 2010BB4301) supported by Natural Science Foundation Project of Chongqing,ChinaProject supported by the Open Fund for Key Laboratory of Manufacture and Test Techniques for Automobile Parts of Ministry of Education Chongqing University of Technology,2003,China
文摘To study the influence of roll casting process parameters on temperature and thermal-stress fields for the AZ31 magnesium alloy sheets,three-dimensional geometric and 3D finite element models for roll casting were established based on the symmetry of roll casting by ANSYS software.Meshing method and smart-sizing algorithm were used to divide finite element mesh in ANSYS software.A series of researches on the temperature and stress distributions during solidification process with different process parameters were done by 3D finite element method.The temperatures of both the liquid-solid two-phase zone and liquid phase zone were elevated with increasing pouring temperature.With the heat transfer coefficient increasing,the two-phase region for liquid-solid becomes smaller.With the pouring temperature increasing and the increase of casting speed,the length of two-phase zone rises.The optimized of process parameters（casting speed 2 m/min,pouring temperature 640 ℃ and heat transfer coefficient 15 kW/（m2·℃） with the water pouring at roller exit was used to produce magnesium alloy AZ31 sheet,and equiaxed grains with the average grain size of 50 μm were achieved after roll casting.The simulation results give better understanding of the temperature variation in phase transformation zone and the formation mechanism of hot cracks in plates during roll casting and help to design the optimized process parameters of roll casting for Mg alloy.
基金Item Sponsored by Fundamental Research Funds for Central Universities of China(N100409010)Project for Key Laboratory of Liaoning Province of China(LS2010065)"111 Project"of Northeastern University of China(B07015)
文摘A new process for swirling flow generation in the submerged entry nozzle （SEN） in continuous casting process of steel was proposed. A rotating electromagnetic field was set up around the SEN to induce swirling flow by Lorentz force. The flow and temperature fields in the SEN and round billet mold with electromagnetic swirling were numerically simulated and then verified by the electromagnetic swirling model experiment of low melting point alloy. The effects of divergent angle of the SEN on the flow and temperature fields in mold with electromagnetic swirling were investigated. The electromagnetic swirling flow generator （EMSFG） could effectively induce swirling flow of molten steel in the SEN, which consequently improved greatly the flow and temperature fields in the mold. Below the nozzle outlet in mold, with the increase of divergent angle, the stream of bulk flow diverged more widely, the high temperature zone shifted up, and the temperature field became more uniform. Above the nozzle outlet in mold, with 350 A electromagnetic swirling, when the divergent angle of the SEN increased, the upward flow velocity and the meniscus temperature first increased and then decreased. With a divergent angle of 60~, the upward flow velocity and meniscus temperature reaced the largest value.
文摘In this study, the effect of melting temperature on the microstructural evolutions, behavior, and corrosion morphology of Hadfield steel in the casting process is investigated. The mold was prepared by the sodium silicate/CO_2 method, using a blind riser, and then the desired molten steel was obtained using a coreless induction furnace. The casting was performed at melting temperatures of 1350, 1400, 1450, and 1500°C, and the cast blocks were immediately quenched in water. Optical microscopy was used to analyze the microstructure, and scanning electron microscopy(SEM) and X-ray diffractrometry(XRD) were used to analyze the corrosion morphology and phase formation in the microstructure, respectively. The corrosion behavior of the samples was analyzed using a potentiodynamic polarization test and electrochemical impedance spectroscopy(EIS) in 3.5 wt% NaCl. The optical microscopy observations and XRD patterns show that the increase in melting temperature led to a decrease of carbides and an increase in the austenite grain size in the Hadfield steel microstructure. The corrosion tests results show that with increasing melting temperature in the casting process, Hadfield steel shows a higher corrosion resistance. The SEM images of the corrosion morphologies show that the reduction of melting temperature in the Hadfield steel casting process induced micro-galvanic corrosion conditions.
基金Item Sponsored by National Natural Science Foundation of China(61174187,71021061,60974091,61104174)Startup Fund of Northeastern University of China(29321006)Basic Scientific Research Foundation of Northeast University of China(N110208001)
文摘The models, algorithms and implementation results of a computerized scheduling system were introduced for the steelmaking-continuous casting process （SCCP） of a steel plant in China. The scheduling of SCCP in this plant required that each cast plan should be processed on time, the charges in the same cast should be processed con- tinuously on the same caster, and the waiting time of the charges which are in front of each caster cannot exceed the given threshold. At the same time, the processing time of charges cannot be conflicted mutually in the same convert- ers or refining furnaces. Based on the research background, a hybrid optimal scheduling approach and its application were discussed. Aiming at the main equipment scheduling, an optimal scheduling method was proposed which con- sisted of equipment assignment algorithm based on dynamic program （DP） technique and conflict elimination algo rithm based on linear program （LP） technique. The approach guarantees that the charges are continuously processed on the same caster. Meanwhile, the requirement for high temperature ladle can also be satisfied due to the ladle matching function. Numerical results demonstrate solution quality, computational efficiency, and values of the mod els and algorithm.
文摘High pressure die casting (HPDC) is a versatile material processing method for mass-production of metal parts with complex geometries,and this method has been widely used in manufacturing various products of excellent dimensional accuracy and productivity. In order to ensure the quality of the components,a number of variables need to be properly set. A novel methodology for high pressure die casting process optimization was developed,validated and applied to selection of optimal parameters,which incorporate design of experiment (DOE),Gaussian process (GP) regression technique and genetic algorithms (GA). This new approach was applied to process optimization for cast magnesium alloy notebook shell. After being trained,using data generated by PROCAST (FEM-based simulation software),the GP model approximated well with the simulation by extracting useful information from the simulation results. With the help of MATLAB,the GP/GA based approach has achieved the optimum solution of die casting process condition settings.
基金funded by National Natural Science Foundation of China(51274155)Provincial Natural Science Foundation of Hubei Province of China(2014CFB819)
文摘A grain-oriented silicon steel strip with AlN as main inhibitor was produced by thin slab casting and rolling（TSCR）process.The microstructure,texture and precipitates of the hot-rolled strip were investigated by use of optical microscope（OM）,X-ray diffractometer,transmission electron microscope（TEM）and energy dispersive spectroscope（EDS）.The result shows that the microstructure and texture exhibit a through-thickness gradient similar to that of the hot-rolled strip produced by conventional high-temperature slab-reheating process;the preferred orientation varies from {110}〈001〉in the surface layer to{001}〈110〉in the center layer,and the Goss texture with a maximum intensity mainly concentrates on the surface layer.In addition,some other texture components,for example rotated Goss texture,form in the 1/4thickness layer,which are not observed in the hotrolled strip produced by conventional high-temperature slab-reheating process.The precipitates in the hot-rolled strip are mainly（Mn,Cu）S and AlN compound particles with dimension of 100-200 nm,and the fine precipitates are significantly less than that in the hot-rolled strip produced by conventional high-temperature slab-reheating process.Moreover,the areal density of the fine precipitates in the center layer is more than that in the surface layer.
文摘Numerical simulation of casting＇s mold filling process is the main and the most important aspect of the foundry CAE technology. But it is time-consuming; it may take dozens of hours or several days. While with the development of computer hardware, numerical simulation of casting＇ s mold filling process has made rapid progress. The simulation results, therefore, have become more and more practical. This study tries to find some clues of the computational time of mold filling process. Firstly, this paper introduces mathematic model and the basic route of numerical simulation of casting＇s mold filling process. Then the computational time of mold filling process has been carefully studied, and some new and useful results have been gained from the study of the computational time. Finally, this paper has given some real applications of numerical simulation of casting＇s mold filling process.
基金supported by the National Natural Science Foundation of China under grant No.50805109the Fundamental Research Funds for the Central Universities under grant No.2011-1a-023
文摘Liners in wet ball mill for mineral processing industry must bear abrasive wear and corrosive wear, and consequently, the service life of the liner made from traditional materials, such as Hadfield steel and alloyed steels, is typically less than ten months. Bimetal liner, made from high Cr white cast iron and carbon steel, has been successfully developed by using liquid-liquid composite lost foam casting process. The microstructure and interface of the composite were analyzed using optical microscope, SEM, EDX and XRD. Micrographs indicate that the boundary of bimetal combination regions is staggered like dogtooth, two liquid metals are not mixed, and the interface presents excellent metallurgical bonding state. After heat treatment, the composite liner specimens have shown excellent properties, including hardness 〉 61 HRC, fracture toughness ak 〉16.5 J.cm2 and bending strength 〉1,600 MPa. Wear comparison was made between the bimetal composite liner and alloyed steel liner in an industrial hematite ball mill of WISCO, and the results of eight-month test in wet grinding environment have proved that the service life of the bimetal composite liner is three times as long as that of the alloyed steel liner.
基金Item Sponsored by the Innovation Fund for Outstanding Scholar of Henan Province of China (0621000700)
文摘The numerical simulation technique was applied to the casting process of a valve-type part. The mold-filling and solidification stages of the casting were numerically analyzed. The filling behavior, solidification sequence, and thermal stress distribution were reproduced and the possible defects, such as cold shut and shrinkage, were predicted. Based on the simulation result, the double-gating system was replaced by a single-gating system. Meanwhile, the chills were used to regulate the solidification sequence of casting. To eliminate the cracks in the casting, the sand core was converted into a canulate one. By modifying the original process, the defects were eliminated and the casting with good quality was obtained.
文摘3-Dvelocity and temperature fields of mold filling and solidification processes of large-sized castingswere calculated,and the efficiency and accuracy of numerical calculation were studied.The mold filling andsolidification processes of large-sized stainless steel,iron and aluminum alloy castings were simulated by using ofnew scheme;their casting processes were optimized,and then applied to produce castings.
基金supported by the Major Science and Technology Project of Changchun City,Jilin Province(No.20210301024GX)the National Natural Science Foundation of China(No.52175335)The authors also appreciate the help pro-vided by China FAW Foundry Co.,LTD and Germany ALUMINUM RHEINFELDEN Group.
文摘The characterization of multiple iron-rich phases in high-pressure die-cast AlSi10MnMg alloy was studied.Attention was focused on the formation and fracture behavior of the primary iron-rich phase((P-IMC)_(I))formed in the shot sleeve and plate-shaped eutectic iron-rich phase in high-pressure die cast(HPDC)AlSi10MnMg alloy.Results show that multiple types of iron-rich phases with various morphologies,in-cluding primary iron-rich phases(polyhedral(P-IMC)_(I) and(P-IMC)_(II))and eutectic iron-rich phases(plate-shaped,net shape,and fish-bone shape),were found in HPDC AlSi10MnMg.Coarse(P-IMC)_(I) formed in the shot sleeve were distributed in the interface between primaryα-Al and binary Al-Si eutectic.Small size(P-IMC)_(II) and various eutectic iron-rich phases formed in the die cavity and they were distributed in Al-Si binary eutectic.The primary iron-rich phases belonged to a simple cubic crystal structure with a lattice constant a=1.265 nm and they exhibited a lateral growth characteristic with a termination of{110}surface.βphase was surrounded byδphase and they coexisted in a plate-shaped iron-rich phase.High-density stacking fault inβphase andδ/βinterface provided an excellent nucleation site forδphase.From mechanical behavior,the stress concentration caused by eutectic iron-rich phases was far less than(P-IMC)_(I) and it would not cause crack initiation along the eutectic cluster boundary.In addition,(P-IMC)_(I) showed the worst deformation coordination with primaryα-Al while the plate-shaped eutectic iron-rich phase exhibited similar deformation characteristics with silicon particles.
基金Item Sponsored by The Central Universities(N100409010)Project for Key Laboratory of Liaoning Province(LS2010065)"111 project" of Northeastern University,China(B07015)
文摘Sliding gate control system is widely employed in continuous casting process of steel to control flow rate of molten steel.As molten steel passes through a sliding gate,uneven flow develops.This will cause asymmetrical distribution of flow and temperature field in mold consequently,formation of vortex near the nozzle and entrapment of CC powder into the molten steel.etc,which have negative effect on process productivity and product quality.To suppress the uneven flow,electromagnetic swirling flow has been proposed to impose on the flow in submerged entry nozzle below the sliding gate.In this study the uneven flow developed by incompletely open sliding gate and the suppression of this uneven flow using electromagnetic swirling flow are numerically studied in round billet continuous casting of steel process.The improvement of the flow and temperature filed in the submerged entry nozzle and mold are investigated.It is found that:The uneven velocity in nozzle can be suppressed by electromagnetic swirling flow,and the flow and temperature field in mold be improved obviously;With the increase of electromagnetic swirling intensity,the effect of uneven flow can be almost completely suppressed.
