The second phase particles were observed during the whole manufacturing process of conventional grain oriented electrical steels, exhibiting that the areal density of particles in the center was obviously higher than ...The second phase particles were observed during the whole manufacturing process of conventional grain oriented electrical steels, exhibiting that the areal density of particles in the center was obviously higher than that on the surface at each manufacturing stage. After hot rolling, the approximately equiaxed grains formed upon recrystallization were present on the sheet surface while the deformation structures were retained in the central part. Thus, the dislocation density on the surface was evidently lower than that in the center and this trend became more noticeable after the first cold rolling. Since new precipitates were mainly nucleated at dislocations during both hot rolling and annealing following cold deformation, the difference in dislocation density resulted in the inhomogeneous distribution of particles through the thickness of sheet. According to this, Goss grains, which were usually found near the surface, tended to grow up more easily during the secondary recrystallization treatment.展开更多
To reduce distribution transformer losses and carbon dioxide emissions, in recent years, the major countries in the world have issued mandatory standards for high-energy efficiency in distribution transformers. In 201...To reduce distribution transformer losses and carbon dioxide emissions, in recent years, the major countries in the world have issued mandatory standards for high-energy efficiency in distribution transformers. In 2013,China has carried out a new standard GB 20052-2013. To meet the update of the standard and energy efficiency,it is important to enhance the magnetic properties of core materials. The new products B18R065 and B20R070 which are developed by Baosteel, are successfully used for grade 1 energy efficiency distribution transformers. And Baosteel becomes one of the companies which can supply both the 0.20 mm and the 0.18 mm gauge grain oriented electrical steels （GOES） in the world. The development principle, material properties, and transformer performance of B18R065 and B20R070 were introduced,which were expected to be a useful reference for materials selection by transformer manufacturers.展开更多
During secondary recrystallization of oriented electrical steels,the dispersed inhibitors strongly hinder grain boundary migration.The existing secondary recrystallization theories,which mainly focus on the initial mi...During secondary recrystallization of oriented electrical steels,the dispersed inhibitors strongly hinder grain boundary migration.The existing secondary recrystallization theories,which mainly focus on the initial migration behavior of grain boundaries,not only fails to clarify the mechanism of secondary recrystallization,but also cannot explain the common phenomenon that smaller Goss grains can eventually engulf all other grains.This study confirms that the significant molar volume effect generated by the precipitation of inhibitors within the ferrite matrix strongly inhibits the coarsening of the central layer inhibitors in steel sheets at high temperatures,but there is still a chance for coarsening of the surface layer inhibitors.Therefore,the surface grains can grow before the growth of grains in the central layer.The highly enhanced elastic anisotropy of ferrite at high temperatures results in slow boundary migration of surface large-sized non-Goss grains towards Goss grains,while surface Goss grain boundaries can quickly migrate towards adjacent small-sized non-Goss grains,allowing Goss grains to gradually accumulate an absolute advantage in larger size,engulf all other grains,and ultimately form a strong Goss texture.展开更多
基金supported by the National Natural Science Foundation of China (No. 50871015)
文摘The second phase particles were observed during the whole manufacturing process of conventional grain oriented electrical steels, exhibiting that the areal density of particles in the center was obviously higher than that on the surface at each manufacturing stage. After hot rolling, the approximately equiaxed grains formed upon recrystallization were present on the sheet surface while the deformation structures were retained in the central part. Thus, the dislocation density on the surface was evidently lower than that in the center and this trend became more noticeable after the first cold rolling. Since new precipitates were mainly nucleated at dislocations during both hot rolling and annealing following cold deformation, the difference in dislocation density resulted in the inhomogeneous distribution of particles through the thickness of sheet. According to this, Goss grains, which were usually found near the surface, tended to grow up more easily during the secondary recrystallization treatment.
文摘To reduce distribution transformer losses and carbon dioxide emissions, in recent years, the major countries in the world have issued mandatory standards for high-energy efficiency in distribution transformers. In 2013,China has carried out a new standard GB 20052-2013. To meet the update of the standard and energy efficiency,it is important to enhance the magnetic properties of core materials. The new products B18R065 and B20R070 which are developed by Baosteel, are successfully used for grade 1 energy efficiency distribution transformers. And Baosteel becomes one of the companies which can supply both the 0.20 mm and the 0.18 mm gauge grain oriented electrical steels （GOES） in the world. The development principle, material properties, and transformer performance of B18R065 and B20R070 were introduced,which were expected to be a useful reference for materials selection by transformer manufacturers.
文摘During secondary recrystallization of oriented electrical steels,the dispersed inhibitors strongly hinder grain boundary migration.The existing secondary recrystallization theories,which mainly focus on the initial migration behavior of grain boundaries,not only fails to clarify the mechanism of secondary recrystallization,but also cannot explain the common phenomenon that smaller Goss grains can eventually engulf all other grains.This study confirms that the significant molar volume effect generated by the precipitation of inhibitors within the ferrite matrix strongly inhibits the coarsening of the central layer inhibitors in steel sheets at high temperatures,but there is still a chance for coarsening of the surface layer inhibitors.Therefore,the surface grains can grow before the growth of grains in the central layer.The highly enhanced elastic anisotropy of ferrite at high temperatures results in slow boundary migration of surface large-sized non-Goss grains towards Goss grains,while surface Goss grain boundaries can quickly migrate towards adjacent small-sized non-Goss grains,allowing Goss grains to gradually accumulate an absolute advantage in larger size,engulf all other grains,and ultimately form a strong Goss texture.
