Cu-4.7%Sn (mass fraction) alloy plate was prepared by the self-developed two-phase zone continuous casting (TZCC) process. The relationship between process parameters of TZCC and surface quality of the alloy plate...Cu-4.7%Sn (mass fraction) alloy plate was prepared by the self-developed two-phase zone continuous casting (TZCC) process. The relationship between process parameters of TZCC and surface quality of the alloy plate was investigated. The microstructure and mechanical properties of the TZCC alloy plate were analyzed. The results show that Cu-4.7%Sn alloy plate with smooth surface can be obtained by means of reasonable matching the entrance temperature of two-phase zone mold and the continuous casting speed. The microstructure of the TZCC alloy is composed of grains-covered grains, small grains with self-closed grain boundaries, columnar grains and equiaxed grains. Compared with cold mold continuous casting Cu-4.7%Sn alloy plate, the room temperature tensile strength and ductility of the TZCC alloy plate are greatly improved.展开更多
A three-dimensional finite-element model of slab continuous casting mold was conducted to clarify the effect of cooling structure on thermal behavior of copper plates. The results show that temperature distribution of...A three-dimensional finite-element model of slab continuous casting mold was conducted to clarify the effect of cooling structure on thermal behavior of copper plates. The results show that temperature distribution of hot surface is mainly governed by cooling structure and heat-transfer conditions. For hot surface centricity, maximum surface temperature promotions are 30 ℃and 15 ℃ with thickness increments of copper plates of 5 mm and nickel layers of 1 ram, respectively. The surface temperature without nickel layers is depressed by 10 ℃ when the depth increment of water slots is 2 mm and that with nickel layers adjacent to and away from mold outlet is depressed by 7℃ and 5 ℃, respectively. The specific trend of temperature distribution of transverse sections of copper plates is nearly free of cooling structure, but temperature is changed and its law is similar to the corresponding surface temperature.展开更多
On the interface of the Cu-Al composite plate from horizontal continuous casting,the eutectic microstructure layer thickness ac-counts for more than 90%of the total interface thickness,and the deformation in rolling f...On the interface of the Cu-Al composite plate from horizontal continuous casting,the eutectic microstructure layer thickness ac-counts for more than 90%of the total interface thickness,and the deformation in rolling forming plays an important role in the quality of the composite plate.The eutectic microstructure material on the interface of the Cu-Al composite plate was prepared by changing the cooling rate of ingot solidification and the deformation in hot compression was investigated.The results show that when the deformation temperature is over 300℃,the softening effect of dynamic recrystallization ofα-Al is greater than the hardening effect,and uniform plastic deformation of eutectic microstructure is caused.The constitutive equation of flow stress in the eutectic microstructure layer was established by Arrhenius hy-perbolic-sine mathematics model,providing a reliable theoretical basis for the deformation of the Cu-Al composite plate.展开更多
The effect of commercial frequency electromagnetic field on the solidification structure and mechanical propertiesof copper hollow blanks prepared by horizontal continuous casting method was investigated. The results ...The effect of commercial frequency electromagnetic field on the solidification structure and mechanical propertiesof copper hollow blanks prepared by horizontal continuous casting method was investigated. The results show thatwhen the electromagnetic field is imposed, columnar grains are evidently refined and fine equiaxed grains areobtained in the inner side of the cross-section. Moreover, with the increase of input current, the equiaxed grain regionwidens and the grains distribute more uniformly in the circumferential direction. Meanwhile, the mechanical properties areremarkably improved by the application of electromagnetic field. When the input current is 140 A, the tensile strengthincreases 15% and the elongation increases 10%. However, the electromagnetic field has no effect on the distribution ofmicroelements.展开更多
According to turbulent theory and characteristics of beam blank continuous casting, 3-D model to represent the flow of beam blank mould is established. The predicted results indicate that the exit obliquity of up 15...According to turbulent theory and characteristics of beam blank continuous casting, 3-D model to represent the flow of beam blank mould is established. The predicted results indicate that the exit obliquity of up 15°(+15°) should be adopted, which will benefit the floatation of non-metallic inclusion and purification of the molten steel. When the nozzle angle is 120°, the flow pattern is reasonable. Proper nozzle depth can be 200mm. Turbulent kinetic of meniscus can be reduced by adopting the square nozzle and suitable area of side outlet when casting speed increases. The results are consistent with those of water model experiment, so the model is exact and reasonable. The model can provide important information for design of SEN and defining of immersion depth.展开更多
A plate's internal quality is very critical, especially for boilers and high-pressure vessels. The ultrasonic test (UT) is the main type of non-destructive flaw detection for heavy plates, which is important becaus...A plate's internal quality is very critical, especially for boilers and high-pressure vessels. The ultrasonic test (UT) is the main type of non-destructive flaw detection for heavy plates, which is important because one of the main reasons for plate defects is ultrasonic flaws. This study, based on Baosteel' s practical experience in the manufacture of heavy plates, elucidates the cause of defect formation by analyzing ultrasonic flaw testing maps and using special equipment, such as the scanning electron microscope, electron probe and the optical microscope. The author puts forward the following improvement measures: ① Ultrasonic flaws are caused by central porosity and segregation,[H] bubbles and inclusion in slabs.②Ultrasonic flaws are more likely to occur in the bottom and top of slabs rather than the other positions in the casting sequence. It is clear that one-quarter of the inner camber' s thickness is accumulated inclusion.③It is clear that overheating in the tundish and the flow of the casting mould have an effect on ultrasonic flaws caused by inclusions.④Soft reduction improves central porosity and segregation,which decreases the number of ultrasonic flaws in the plate.展开更多
Based on turbulent theory, a 3D coupled model of fluid flow and solidification was built using finite difference method and used to study the influence of superheating degree and casting speed on fluid flow and solidi...Based on turbulent theory, a 3D coupled model of fluid flow and solidification was built using finite difference method and used to study the influence of superheating degree and casting speed on fluid flow and solidification, analyze the interaction between shell and molten steel, and compare the temperature distribution under different technological conditions. The results indicate that high superheating degree can lengthen the liquid-core depth and make the crack and breakout possible, so suitable superheating should be controlled within 35℃ according to the simulation results. Casting speed which is one of the most important technological parameters of improving production rate, should be controlled between 0. 85 m/min and 1.05 m/min and the caster has great potential in the improvement of blank quality.展开更多
In continuous casting rolling process, the deformed body is different from the hot rolling strip. The metal in casting rolling zone is first assumed to be viscous fluid and the mathematical model of casting rolling fo...In continuous casting rolling process, the deformed body is different from the hot rolling strip. The metal in casting rolling zone is first assumed to be viscous fluid and the mathematical model of casting rolling force is established, then the calculating formula for casting rolling torque is derived. In addition, considering the effects of deforming cone and appendant torque of rotary junctions sealing ring, the calculating model which accords with casting rolling condition is found out. Theoretical formula is proved by experiment.展开更多
In order to describe the thermal–mechanical behavior of the ship plate steel continuous casting slab during solidification end heavy reduction(HR)process accurately,its constitutive behavior was investigated by a sin...In order to describe the thermal–mechanical behavior of the ship plate steel continuous casting slab during solidification end heavy reduction(HR)process accurately,its constitutive behavior was investigated by a single-pass thermal compression experiment.According to the deformation features of wide thick continuous casting slab with HR,the simulation temperature ranged from 1173 to 1573 K with strain rates of 0.0001,0.001,0.01 and 0.1 s^(-1).Three different constitutive models,the modified Johnson–Cook(JC)model,the modified Zerilli–Armstrong(ZA)model and the Arrhenius model,were established according to the obtained true stress–strain curves.The average relative error of the modified JC model,the modified ZA model and the Arrhenius model are 10.82%,9.96%and 6.21%,respectively.Considering the obvious softening effect of the flow curve at a low strain rate,the secondary softening factor under the interaction of low strain rate and the temperature was introduced in the original Arrhenius model.Compared to the Arrhenius model,the modified Arrhenius model error decreased from 6.21%to 4.73%.展开更多
Finite element models of steady heat conduction for cross section of beam blank mold were developed by using ABAQUS software. The effect of mold grinding thickness, cooling water velocity, diameter of restrietor rods ...Finite element models of steady heat conduction for cross section of beam blank mold were developed by using ABAQUS software. The effect of mold grinding thickness, cooling water velocity, diameter of restrietor rods and water channel design on hot face temperature was analyzed in detail. Attention was focused on the peak temperature and temperature uniformity along hot face. The results showed that the peak temperature of existing mold, about 337.2 ℃, is located in the fillet, and two valleys of hot face temperature are found in flange corner and junction of wide face and narrow face, respectively. Decreasing mold thickness, increasing cooling water velocity and increasing diameter of restrictor rods can all reduce peak temperature and improve temperature uniformity along hot race at the expense of lower overall temperature. Redesigning the water channel can decrease peak temperature and thermal gradient of mold without lowering overall temperature of hot face. In particular, the small hole design can improve temperature uniformity across hot face and obtain the best advantage.展开更多
基金Project(51374025) supported by the National Natural Science Foundation of ChinaProject(2014Z-05) supported by the State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing,ChinaProject(2152020) supported by the Beijing Natural Science Foundation,China
文摘Cu-4.7%Sn (mass fraction) alloy plate was prepared by the self-developed two-phase zone continuous casting (TZCC) process. The relationship between process parameters of TZCC and surface quality of the alloy plate was investigated. The microstructure and mechanical properties of the TZCC alloy plate were analyzed. The results show that Cu-4.7%Sn alloy plate with smooth surface can be obtained by means of reasonable matching the entrance temperature of two-phase zone mold and the continuous casting speed. The microstructure of the TZCC alloy is composed of grains-covered grains, small grains with self-closed grain boundaries, columnar grains and equiaxed grains. Compared with cold mold continuous casting Cu-4.7%Sn alloy plate, the room temperature tensile strength and ductility of the TZCC alloy plate are greatly improved.
基金Project(51004031) supported by the National Natural Science Foundation of ChinaProject(50925415) supported by the National Outstanding Young Scientist Foundation of China+1 种基金Project(20100042120012) supported by the Special Research Fund for Doctoral Programs of Ministry of Education of ChinaProject(N090402022) supported by the Fundamental Research Funds for the Central Universities of China
文摘A three-dimensional finite-element model of slab continuous casting mold was conducted to clarify the effect of cooling structure on thermal behavior of copper plates. The results show that temperature distribution of hot surface is mainly governed by cooling structure and heat-transfer conditions. For hot surface centricity, maximum surface temperature promotions are 30 ℃and 15 ℃ with thickness increments of copper plates of 5 mm and nickel layers of 1 ram, respectively. The surface temperature without nickel layers is depressed by 10 ℃ when the depth increment of water slots is 2 mm and that with nickel layers adjacent to and away from mold outlet is depressed by 7℃ and 5 ℃, respectively. The specific trend of temperature distribution of transverse sections of copper plates is nearly free of cooling structure, but temperature is changed and its law is similar to the corresponding surface temperature.
基金This work was financially supported by the National Key Research and Development Program of China(No.2018YFA0707303)the National Natural Science Foundation for Distinguished Young Scholars of China(No.51925401).
文摘On the interface of the Cu-Al composite plate from horizontal continuous casting,the eutectic microstructure layer thickness ac-counts for more than 90%of the total interface thickness,and the deformation in rolling forming plays an important role in the quality of the composite plate.The eutectic microstructure material on the interface of the Cu-Al composite plate was prepared by changing the cooling rate of ingot solidification and the deformation in hot compression was investigated.The results show that when the deformation temperature is over 300℃,the softening effect of dynamic recrystallization ofα-Al is greater than the hardening effect,and uniform plastic deformation of eutectic microstructure is caused.The constitutive equation of flow stress in the eutectic microstructure layer was established by Arrhenius hy-perbolic-sine mathematics model,providing a reliable theoretical basis for the deformation of the Cu-Al composite plate.
文摘The effect of commercial frequency electromagnetic field on the solidification structure and mechanical propertiesof copper hollow blanks prepared by horizontal continuous casting method was investigated. The results show thatwhen the electromagnetic field is imposed, columnar grains are evidently refined and fine equiaxed grains areobtained in the inner side of the cross-section. Moreover, with the increase of input current, the equiaxed grain regionwidens and the grains distribute more uniformly in the circumferential direction. Meanwhile, the mechanical properties areremarkably improved by the application of electromagnetic field. When the input current is 140 A, the tensile strengthincreases 15% and the elongation increases 10%. However, the electromagnetic field has no effect on the distribution ofmicroelements.
文摘According to turbulent theory and characteristics of beam blank continuous casting, 3-D model to represent the flow of beam blank mould is established. The predicted results indicate that the exit obliquity of up 15°(+15°) should be adopted, which will benefit the floatation of non-metallic inclusion and purification of the molten steel. When the nozzle angle is 120°, the flow pattern is reasonable. Proper nozzle depth can be 200mm. Turbulent kinetic of meniscus can be reduced by adopting the square nozzle and suitable area of side outlet when casting speed increases. The results are consistent with those of water model experiment, so the model is exact and reasonable. The model can provide important information for design of SEN and defining of immersion depth.
文摘A plate's internal quality is very critical, especially for boilers and high-pressure vessels. The ultrasonic test (UT) is the main type of non-destructive flaw detection for heavy plates, which is important because one of the main reasons for plate defects is ultrasonic flaws. This study, based on Baosteel' s practical experience in the manufacture of heavy plates, elucidates the cause of defect formation by analyzing ultrasonic flaw testing maps and using special equipment, such as the scanning electron microscope, electron probe and the optical microscope. The author puts forward the following improvement measures: ① Ultrasonic flaws are caused by central porosity and segregation,[H] bubbles and inclusion in slabs.②Ultrasonic flaws are more likely to occur in the bottom and top of slabs rather than the other positions in the casting sequence. It is clear that one-quarter of the inner camber' s thickness is accumulated inclusion.③It is clear that overheating in the tundish and the flow of the casting mould have an effect on ultrasonic flaws caused by inclusions.④Soft reduction improves central porosity and segregation,which decreases the number of ultrasonic flaws in the plate.
文摘Based on turbulent theory, a 3D coupled model of fluid flow and solidification was built using finite difference method and used to study the influence of superheating degree and casting speed on fluid flow and solidification, analyze the interaction between shell and molten steel, and compare the temperature distribution under different technological conditions. The results indicate that high superheating degree can lengthen the liquid-core depth and make the crack and breakout possible, so suitable superheating should be controlled within 35℃ according to the simulation results. Casting speed which is one of the most important technological parameters of improving production rate, should be controlled between 0. 85 m/min and 1.05 m/min and the caster has great potential in the improvement of blank quality.
文摘In continuous casting rolling process, the deformed body is different from the hot rolling strip. The metal in casting rolling zone is first assumed to be viscous fluid and the mathematical model of casting rolling force is established, then the calculating formula for casting rolling torque is derived. In addition, considering the effects of deforming cone and appendant torque of rotary junctions sealing ring, the calculating model which accords with casting rolling condition is found out. Theoretical formula is proved by experiment.
基金The present work was financially supported by the National Natural Science Foundation of China(Nos.51974078 and U20A20272)Science and Technology Planning Project of Liaoning Province(Nos.2022JH2/101300002 and 2022JH25/10200003)the Fundamental Research Funds for the Central Universities of China(No.N2125018).
文摘In order to describe the thermal–mechanical behavior of the ship plate steel continuous casting slab during solidification end heavy reduction(HR)process accurately,its constitutive behavior was investigated by a single-pass thermal compression experiment.According to the deformation features of wide thick continuous casting slab with HR,the simulation temperature ranged from 1173 to 1573 K with strain rates of 0.0001,0.001,0.01 and 0.1 s^(-1).Three different constitutive models,the modified Johnson–Cook(JC)model,the modified Zerilli–Armstrong(ZA)model and the Arrhenius model,were established according to the obtained true stress–strain curves.The average relative error of the modified JC model,the modified ZA model and the Arrhenius model are 10.82%,9.96%and 6.21%,respectively.Considering the obvious softening effect of the flow curve at a low strain rate,the secondary softening factor under the interaction of low strain rate and the temperature was introduced in the original Arrhenius model.Compared to the Arrhenius model,the modified Arrhenius model error decreased from 6.21%to 4.73%.
文摘Finite element models of steady heat conduction for cross section of beam blank mold were developed by using ABAQUS software. The effect of mold grinding thickness, cooling water velocity, diameter of restrietor rods and water channel design on hot face temperature was analyzed in detail. Attention was focused on the peak temperature and temperature uniformity along hot face. The results showed that the peak temperature of existing mold, about 337.2 ℃, is located in the fillet, and two valleys of hot face temperature are found in flange corner and junction of wide face and narrow face, respectively. Decreasing mold thickness, increasing cooling water velocity and increasing diameter of restrictor rods can all reduce peak temperature and improve temperature uniformity along hot race at the expense of lower overall temperature. Redesigning the water channel can decrease peak temperature and thermal gradient of mold without lowering overall temperature of hot face. In particular, the small hole design can improve temperature uniformity across hot face and obtain the best advantage.